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Background: Intravenous immunoglobulin is a replacement therapy for patients living with primary immunodeficiencies. Each batch of intravenous immunoglobulin is required by the Food and Drug Administration to contain threshold levels of measles neutralising antibodies. Widespread use of the measles vaccine has decreased measles antibody potency in the United States plasma supply. There is limited data on measles antibody trough levels in treated primary immunodeficiency patients. The aim of this sub-analysis was to evaluate the measles antibody trough levels in treated primary immunodeficiency patients., Methods: GMX07 was an open-label, two-period, crossover bioequivalence study which randomized 33 adult patients with primary immunodeficiency disease in 16 centres across the United States, the United Kingdom and Hungary. Eligible adult patients received five infusions of Gammaplex® 5% followed by five infusions of Gammaplex® 10%, or vice versa, on either a 21- or 28-day dosing regimen. The trial included 15 paediatric patients who were not randomized, receiving only five infusions of 10% product. This sub-analysis measured trough levels of measles neutralising antibodies using a Vero cell-based measles virus neutralisation assay., Results: Median measles antibody trough levels were ~ 1300 mIU/mL with no significant difference between Gammaplex 5% and Gammaplex 10% treatment (p >  0.9) or the 21-day or 28-day dosing regimen (p >  0.3). There was also no difference between mean measles neutralising antibody levels following Gammaplex 10% in adult or paediatric patients., Conclusions: Levels of measles neutralising antibodies in the 5% and 10% formulations of this intravenous immunoglobulin product provided protective antibodies well above accepted thresholds and were similar in adult and paediatric patients across both 21-day and 28-day dosing regimens. Switching between Gammaplex products did not affect antibody levels., Trial Registration: ClinicalTrials.gov NCT01963143., Competing Interests: I have read the journal's policy and the authors of this manuscript have the following competing interests: VR, MP and JM are employees of BPL., (Copyright: © 2025 Rajendram et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

IKKα, encoded by CHUK, is crucial in the non-canonical NF-κB pathway and part of the IKK complex activating the canonical pathway alongside IKKβ. The absence of IKKα causes fetal encasement syndrome in humans, fatal in utero, while an impaired IKKα-NIK interaction was reported in a single patient and causes combined immunodeficiency. Here, we describe compound heterozygous variants in the kinase domain of IKKα in a female patient with hypogammaglobulinemia, recurrent lung infections, and Hay-Wells syndrome-like features. We showed that both variants were loss-of-function. Non-canonical NF-κB activation was profoundly diminished in stromal and immune cells while the canonical pathway was unexpectedly partially impaired. Reintroducing wt CHUK restored non-canonical NF-κB activation. The patient had neutralizing autoantibodies against type I IFN, akin to non-canonical NF-κB pathway deficiencies. Thus, this is the first case of biallelic CHUK mutations disrupting IKKα kinase function, broadening non-canonical NF-κB defect understanding, and suggesting IKKα's role in canonical NF-κB target gene expression in humans., (© 2025 Riller et al.)

The Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling cascade is an evolutionarily conserved signal transduction pathway that regulates many vital cellular processes, including immune function and hematopoiesis. Human genetic variants that disrupt JAK-STAT signaling are being found to cause a rapidly increasing number of diseases, including both germline-encoded inborn errors of immunity (IEI) and acquired somatic variants, causing a so-called phenocopy of the IEI. Multiple genetic mechanisms are responsible for this growing group of JAK-STAT diseases including loss-of-function, gain-of-function, and dominant negative effects. In this review, we discuss the clinical presentation and pathogenesis of all currently described JAK-STAT defects, as well as provide an overview of the guiding principles to consider in diagnosing and treating these conditions., Competing Interests: Disclosure statement S.E.T. holds a Tier 1 Canada Research Chair in pediatric precision health and is the Aubrey J. Tingle Professor of Pediatric Immunology. S.S. is supported by a University of British Columbia Four Year Doctoral Fellowship. This work was supported by grants from the Canadian Institutes of Health Research (PJT-178054 to S.E.T.) and Genome British Columbia (SIP007 to S.E.T.). This work was also supported in part by the Intramural Research Program of the National Institute of Allergy and Infectious Diseases, National Institutes of Health. Disclosure of potential conflict of interest: The authors declare that they have no relevant conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes severe illness and mortality in patients with immunodeficiency. Although vaccination has been recommended, the induction of protective antibodies by immunization, and thus the disease-preventive effect, has proven insufficient in immunodeficient patients, especially in those with predominantly antibody deficiency. A monoclonal antibody combination of tixagevimab and cilgavimab (TIX/CIL) was developed as a pre-exposure prophylaxis (PrEP). In this study, we investigated the post-PrEP increase in antiviral antibody titers and detailed the breakthrough infections that occurred despite PrEP in Japanese immunodeficient patients who had received TIX/CIL., Methods: Blood samples were collected before and after TIX/CIL administration between November 2022 and August 2023. Antibody titers against the S-protein of SARS-CoV-2 were measured to evaluate TIX/CIL-induced protection. Information regarding breakthrough infection, as evidenced by positive antigen and/or PCR tests, was collected., Results: A significant increase in the anti-S antibody titer was observed in all 89 immunodeficient patients who had received TIX/CIL. However, 14 (16 %) patients experienced breakthrough SARS-CoV-2 infections, of which one died of respiratory failure., Conclusion: The shift in the SARS-CoV-2 circulating strain might have reduced the efficacy of TIX/CIL, leading to an increased number of breakthrough infections., (Copyright © 2024 Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases, and Japanese Society for Infection Prevention and Control. Published by Elsevier Ltd. All rights reserved.)

Inborn errors of immunity (IEIs), also known as primary immunodeficiencies, are a group of genetic disorders affecting the development and function of the immune system. While IEIs traditionally present with recurrent infections, an increasing number of cases manifest with early-onset severe atopy, including atopic dermatitis, food allergies, asthma, and allergic rhinitis-features that are often overlooked. This can lead to delayed diagnosis and treatment, which is crucial for IEI patients due to the risk of severe infections. We conducted a literature search and reviewed all IEIs that can present with early-onset severe atopy. The hallmark features of these disorders often include early-onset, persistent, and severe atopic dermatitis, food allergies, and recurrent episodes of asthma, which may be refractory to treatments. Additionally, we discuss the importance of recognizing such severe atopy as a potential indicator of an underlying immune deficiency, particularly when accompanied by unusual infections, growth failure, or autoimmunity. This review aims to raise awareness of this association and emphasize the need for early diagnosis and genetic testing in patients with atypical or treatment-resistant allergic diseases, allowing for more timely diagnosis of underlying immunodeficiencies and appropriate treatments.

Autoinflammatory bone diseases (AIBDs) constitute a recently identified subset of autoinflammatory diseases. These conditions are characterized by an exaggerated inflammatory response in the bones without any apparent etiology. Inflammatory bone lesions associated with AIBDs exhibit chronic inflammation, are typically culture-negative, and do not exhibit discernible microorganisms on histopathological examination. The most common and representative AIBD is chronic non-bacterial osteomyelitis (CNO), which is also known as chronic recurrent multifocal osteomyelitis. Another variant of CNO, which is typically observed in older teenagers or adults, is known as synovitis, acne, hyperostosis, pustulosis, osteitis syndrome. This condition is distinguished by its notable skin manifestations. Advancements in genetic research have led to the identification of three novel monogenic subtypes within the category of AIBDs. These include Majeed syndrome, pyogenic arthritis, pyoderma gangrenosum, and acne syndrome, and interleukin-1 receptor antagonist deficiency syndrome. Another monogenic AIBD, called cherubism, affects only the maxilla and mandible. Data on the diagnosis and treatment of these rare diseases are extremely limited. However, if not diagnosed and treated promptly, it can result in significant complications, including severe disability and mortality. Thus, it is imperative to maintain a high level of clinical awareness of these diseases. These rare diagnoses should be considered in patients with musculoskeletal complaints in whom no specific etiology can be identified or in patients with systemic manifestations such as cutaneous and gastrointestinal symptoms or fever. In such patients, the diagnostic process, which encompasses imaging and genetic studies, should be initiated promptly., Competing Interests: Conflict of Interest: The authors declare that they have no conflict of interest.

Low immunoglobulin E (IgE) levels are defined as values below 2.5 IU/mL. Selective IgE deficiency (sIgED) refers to reduced serum IgE levels in patients with normal IgA/G/M levels. We evaluated 677 patients with low IgE levels. Recurrent infections (78.8 %), a history of allergy (27.3 %), and autoimmune/inflammatory diseases (18.3 %) are common. The primary immunodeficiency disease (PID) (n = 483, 71.3 %) diagnoses include 313 (46.2 %) patients with antibody deficiency and 119 (17.6 %) with combined immunodeficiency. Genetic pathogenic variants were present in 154 out of 207 PID patients. Within sIgED group, 23 (19.8 %) had primary immunodeficiencies. We observed a high prevalence of autoimmune/inflammatory diseases, allergies, malignancies, and PID among patients with low IgE levels. Therefore, clinicians should be vigilant when evaluating patients with low IgE levels, as this finding may indicate an underlying systemic disease or PID., Competing Interests: Declaration of competing interest Authors declare that there is no conflict of interest and no funding., (Copyright © 2024. Published by Elsevier Inc.)

Background: Infections are a major cause of morbidity in children with primary or secondary immunodeficiency, and have a negative impact on overall outcome., Objectives: This narrative review presents select paediatric-specific aspects regarding the clinical impact, diagnosis, management, and follow-up of infectious complications in patients with primary and secondary immunodeficiencies., Sources: PubMed until January 2024 and searched references in identified articles including the search terms: infection, immunodeficiency or cancer, diagnostics, antimicrobial agents, bacteria or fungus or virus, and follow-up., Content: Major advances have been made in the early detection and management of patients with primary immunodeficiency, and multiple analyses report in children with cancer on risk groups and periods of risk for infectious complications. Although many diagnostic tools are comparable between children and adults, specific considerations have to be applied, such as minimizing the use of radiation. Antimicrobial drug development remains a major challenge in the paediatric setting, which includes the establishment of appropriate dosing and paediatric approval. Last, long-term follow-up and the impact of late effects are extremely important to be considered in the management of immunocompromised paediatric patients., Implications: Although infectious disease supportive care of immunocompromised children and adolescents has considerably improved over the last three decades, close international collaboration is needed to target the specific challenges in this special population., (Copyright © 2024. Published by Elsevier Ltd.)

Introduction: Inborn errors of immunity include a broad spectrum of genetic diseases, in which a specific gene mutation might alter the entire emphasis and approach for an individual patient., Objective: To conduct a comprehensive analysis of the correlation between phenotypic and molecular diagnoses in patients with confirmed inborn errors of immunity at a tertiary hospital in Cali, Colombia., Materials and Methods: We conducted a retrospective study in which we sequentially evaluated all available institutional medical records with a diagnosis of inborn errors of immunity., Results: In the Clinical Immunology Service of the Hospital Universitario del Valle, 517 patients were evaluated. According to the IUIS-2022 classification, 92 patients (17.35%) were definitively diagnosed with an inborn error of immunity. Of these, 38 patients underwent genetic studies. The most prevalent category was predominantly antibody deficiencies (group III) (38/92 - 41.3%). A broad spectrum of genetic defects, novel and previously reported, were described, including mutations in the following genes: ATM, BTK, ERBIN, MAB21L2, RAG2, SAVI, SH2D1A, STAT1, SYK, and TMEM173. Less frequent findings included cases of the WHIM syndrome, SYK gain-of-function, and IL-7 deficiency., Conclusions: The establishment of the Clinical Immunology Service in the Hospital Universitario del Valle has emerged as a pivotal resource, catering to individuals with limited financial means and covered by public health insurance within the southwest region of Colombia. Molecular genetics confirmatory diagnosis was achieved in 38 patients (41.3%) with inborn errors of immunity and changed the diagnosis in 24 cases (26%).

Introduction. Specific antibody deficiency is an innate error of humoral immunity characterized by normal levels of immunoglobulin isotypes, recurrent infections, and a reduced reaction to polysaccharide antigens in vaccines. Objective. To describe the clinical and immunological characteristics of patients with specific antibody deficiency attending a pediatric hospital in Bogotá between May 2021 and September 2023. Materials and methods. We reviewed the medical records of 16 patients with specific antibody deficiency. Results. The median age at diagnosis was six and a half years. Nine were male, and 7 had a history of prematurity. Eleven patients had adequate nutritional status, and 7 had standard height. The most frequent recurrent infection was pneumonia, affecting 12 patients; more than half of them experienced some associated complications. The most common phenotype was moderate, and 15 of the individuals received immunoglobulin as definitive treatment. Conclusion. Specific antibody deficiency is a frequently underdiagnosed functional alteration of the immune system. It should be suspected in patients experiencing recurrent otitis media and pneumonia or in cases complicated by septic shock, pleural effusion, or necrotizing pneumonia.

Introduction: Predominant antibody deficiency is the most frequent group of innate immunity errors, but information about patients’ nutritional status is scarce., Objectives: To characterize the nutritional status of Colombian patients with predominant antibody deficiencies., Material and Methods: Material and methods. We analyzed medical charts of patients with predominant antibody deficiency in a pediatric hospital in Bogotá., Results: We analyzed 55 medical charts. The most frequent diagnoses were specific deficiencies of polysaccharide antibodies and immunoglobulin A, common variable immunodeficiency, and agammaglobulinemia. More than 70% of the patients had sinopulmonary infections, with pneumonia being the most frequent, followed by otitis and sinusitis. In children under five years, 45% had adequate weight for their height, 18% had a risk of malnutrition, and 18% had moderate acute malnutrition. Four-point-five percent had obesity, 4.5% showed overweight, and 9% had a risk of being overweight. Of those older than five years, 54% had an adequate body mass index, 22.5% showed overweight, 9.6% were at risk of thinness, and 9.6% were thin. We found that the risk of short stature and short stature per se were more frequent than the expected height in these patients. The percentages of patients with short stature were higher than those reported nationally., Conclusions: Due to the epidemic of childhood obesity, it will be more frequent to find overweight or obesity in children above five years. Therefore, finding short stature could be a more sensitive alarm sign for predominant antibody deficiency.

Introduction. Inborn errors of immunity are frequently associated with bronchiectasis. The diagnostic performance of these inborn errors has improved because the association of some of these entities with progressive airway damage is better known. This knowledge has allowed recognition and appropriate intervention reducing deterioration of the pulmonary function and improving quality of life. Objective. To describe a group of patients with bronchiectasis not related to cystic fibrosis who were diagnosed with inborn errors of immunity and have been studied in an immunology reference center in Colombia. Materials and methods. We conducted an observational, descriptive, and retrospective study with participating patients under 18 years, diagnosed with inborn errors of immunity and non-cystic fibrosis bronchiectasis, between December 2013 and December 2023 at the Fundación Valle del Lili in Cali, Colombia. Results. Seventeen patients were diagnosed with non-cystic fibrosis bronchiectasis and inborn errors of immunity. Their mean age was nine years. The lower pulmonary lobe was the most frequently affected segment, and in most cases, unilaterally. The most prevalent alteration was predominantly antibody inmunodeficiency, followed by combined immunodeficiencies associated with syndromes. Thirteen patients had humoral immunity compromise, while 4 exhibited humoral and cellular immunity alterations. Additionally, 12 patients presented genetic mutations related to their phenotype. Thirteen patients, underwent supplementation with intravenous immunoglobulin, and 3 died. Conclusion. The inborn errors of immunity most frequently associated with noncystic fibrosis bronchiectasis, were predominantly antibody deficiency and combined immunodeficiencies with syndromic features.

Introduction: Non-cystic fibrosis bronchiectasis is a complex medical condition with multiple etiologies, characterized by chronic productive cough and radiologic evidence of airway lumen dilation and wall thickening. Associated exacerbations and declining lung function contribute to increasing disability and mortality. There are no data about the prevalence of non-cystic fibrosis bronchiectasis etiologies in the Colombian population., Objective: To investigate non-cystic fibrosis bronchiectasis etiology and clinical characteristics in adults evaluated in the southwest of Colombia., Materials and Methods: We conducted a cross-sectional, non-interventional study. Subjects diagnosed with non-cystic fibrosis bronchiectasis were referred to by their healthcare providers and then enrolled between October 2018 and April 2021. Medical records and radiological studies were evaluated. Participants underwent laboratory tests, including complete blood count, serum immunoglobulin levels, and, in some cases, additional tests., Results: We included 161 subjects. The average age was 50 years old, and 59% were females. Bronchiectasis etiology was identified in 84.6% of the cases. Postinfectious (34.6%) and immune disorders (25.3%), represented by autoimmunity (13.6%) and immunodeficiency (11.7%), were the leading causes. Gender differences were noted in autoimmune (females: 18.8% versus males: 6.1%, p = 0.021) and immunodeficiency-related bronchiectasis (males: 21.2% versus females 5.2%, p = 0.002). Immunodeficiencies-associated bronchiectases were more frequent in subjects under 50 years of age, while chronic obstructive pulmonary disease-associated bronchiectases were common in subjects over 50 years of age., Discussion: The etiologies of non-cystic fibrosis bronchiectasis in Colombia are diverse, exhibiting notable differences from other global regions. Serum immunoglobulin levels and clinical immunologist consultation should be prioritized in diagnosing patients with unclear bronchiectasis etiology, particularly those with recurrent sinopulmonary infections.

Individuals with certain primary immunodeficiency disorders (PID) may be unable to clear poliovirus infection after exposure to oral poliovirus vaccine (OPV). Over time, vaccine-related strains can revert to immunodeficiency-associated vaccine-derived poliovirus (iVDPVs) that can cause paralysis in the patient and potentially spread in communities with low immunity. We reviewed the efforts for detection and management of PID patients with iVDPV infections and the epidemiology through an analysis of 184 cases reported to the World Health Organization (WHO) during 1962-2024 and a review of polio program and literature reports. Most iVDPV patients (79%) reported in the WHO Registry were residents in middle-income countries and almost half (48%) in the Eastern Mediterranean Region. Type 2 iVDPV was most frequently isolated (53%), but a sharp decline was observed after the switch to bivalent OPV in 2016, with only six cases reported during 2017-2024 compared to 63 during 2009-2016. Patients with common variable immunodeficiency have longer excretion of iVDPV than with other PID types. Implementation of sensitive sentinel surveillance to detect cases of iVDPV infection in high-risk countries and offer antiviral treatment to patients is challenged by competition with other health priorities and regulatory hurdles to the compassionate use of investigational antiviral drugs.

Selective IgM deficiency (SIgMD) has recently been included in the inborn errors of immunity classification. SIgMD has conflicting diagnostic criteria and diverse clinical and immunological findings. We aimed to assess the clinical and laboratory profiles of patients with SIgMD and to compare the data of patients diagnosed using two inclusion criteria. This was a descriptive, retrospective, observational, collaborative study. Patients were included according to the following definitions: Group 1, IgM levels < 0.20 g/L in children and < 0.30 g/L in adults, and Group 2, serum IgM levels below 2SD and, for both, absence of associated immunological diseases or secondary causes. The protocol was approved by the Ethics Committee, and patients provided consent. In total, 75 patients were included: 37 (16 M:21F; mean age, 52.92) and 38 (13 M:25F; mean age, 53.47) in Groups 1 and 2, respectively. The most frequent clinical manifestations were allergic rhinitis (G1, 45.9%; G2, 36.8%), asthma (G1, 37.8%; G2, 28.9%), and pulmonary infections (G1, 27.03%; G2, 21.05%). Chromosomopathies (16.22%) and neoplasia (13.51%) were more frequent in G1, whereas URTI (23.68%) and skin infections (23.68%) were more common in G2. There was no difference in sex or mean age at symptom onset between both groups of patients. Regarding the clinical picture, 90.7% of the lesions were benign (68/75). Chromosomopathies may be associated with SIgMD, suggesting the need to quantify serum IgM levels in these cases. Considering the possibility of developing autoimmunity, neoplasia, and common variable immunodeficiency, it is advisable to follow up patients with SIgMD., Competing Interests: Declarations. Ethics approval: This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Ethics Committee of University Center FMABC on January 17, 2021 (CAAE 52536915.5.0000.0082). All the authors were consulted and consented to participate and submit to the Journal of Clinical Immunology. Consent to participate: Informed consent was obtained from all individual participants included in the study. The consent was read and explained for each participant, and all the text was previously revised by the ethical committee. Patients younger than 18 years old had a specific consent, and the parent or legal guardian also signed the consent to participate in the study. Consent for publication: The patient or in the case of patients less than 18 years old, his/her parent or legal guardian authorized the publication of the results without identifying their names. The patients were nominated by numbers to maintain their identity anonymous. Conflict of interest: No conflicts of interest related to this project. ASG belongs to the editorial board. ASG has been a consultant and/or speaker for CSL Behring, Takeda, and Catalyst. CMK has been a speaker for Takeda. PRJ has been a consultant and/or speaker for CSL Behring, Takeda, Novartis, and Sanofi. EM has been a speaker for Takeda, CSL Behring, Novartis, and Sanofi and a consultant for Takeda and CSL Behring. CSA has been a speaker for Takeda, CSL Behring, Sanofi, and Roche and a consultant for PTC, EUSA Pharma, and Sanofi., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

The concept of an "immunological continuum model," introduced by McGonagle and McDermott in 2006, redefines the traditional dichotomy between autoimmunity and autoinflammation, proposing a spectrum where innate and adaptive immune dysregulation can co-occur, reflecting a more nuanced understanding of immune disorders. Systemic lupus erythematosus (SLE) exemplifies the complexity of this continuum, often displaying manifestations of autoimmunity, autoinflammation, and immunodeficiency. The interplay between genetic, epigenetic, hormonal, psychological, and environmental factors contributes to its distinctive immunopathological signatures. Historically recognized as a systemic disease with diverse clinical manifestations, SLE is primarily a polygenic autoimmune condition but can, however, present in monogenic forms. Examining SLE through the lens of the immunological continuum model allows for emphasis on the contributions of both innate and adaptive immunity. SLE and primary immunodeficiencies share genetic susceptibilities and clinical manifestations. Additionally, autoinflammatory mechanisms, such as inflammasome activation and interferonopathies, can play a role in SLE pathogenesis, illustrating the disease's position at the crossroads of immune dysregulation. Recognizing the diverse clinical expressions of SLE and its mimickers is critical for accurate diagnosis and targeted therapy. In conclusion, the immunological continuum model provides a comprehensive framework for understanding SLE, acknowledging its multifaceted nature and guiding future research and clinical practice toward more effective and individualized treatments. After the Mosaic of Autoimmunity, it is now the time to focus and attempt to solve the intricate mosaic of SLE., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Major Histocompatibility Complex Class II Deficiency is a rare primary immunodeficiency disease with autosomal recessive inheritance. It is characterized by the absence of Major Histocompatibility Complex Class II molecules on the surface of immune cells. In this article, we will present a four-month-old baby girl who presented with recurrent fever and progressive exacerbation of respiratory symptoms since a month ago. Relevant examinations suggested pancytopenia, a decrease in CD4 and CD3 ratio, and CD4/CD8 inversion, hypogammaglobulinemia, and diagnosis of hemophagocytic syndrome during treatment which all led to the consideration of the presence of immunodeficiency diseases, and the diagnosis of Major Histocompatibility Complex Class II Deficiency was made by peripheral blood whole-exon sequencing (WES). This case is remarkable in that it reveals features of hemophagocytic syndrome in a Major Histocompatibility Complex Class II Deficiency infant, most probably caused by cytomegalovirus, which rarely reported before, and the Major Histocompatibility Complex Class II Deficiency caused by a novel mutation site in the RFXANK gene which never reported, and it also describes the diagnostic and therapeutic course in detail. In addition, we have summarized the information related to Major Histocompatibility Complex Class II Deficiency triggered by mutations in the RFXANK gene to assist clinicians in early recognition and diagnosis., Competing Interests: Declarations. Conflict of interest: The authors declare no competing interests., (© 2024. The Author(s).)

Background and Objective: We aimed to evaluate clinical characteristics and therapeutic efficacy of pulmonary cryptococcosis (PC) in patients with different immune status in a large multicenter population to support appropriate clinical management of this public health threat., Methods: We retrospectively investigated the medical records of 510 patients with PC from January 2014 to June 2023 in 10 representative regional tertiary teaching hospitals in Hubei province of China, and clinical data of these patients were then stratified by different immune statuses., Results: Immunocompetent (IC) patients accounted for 68.8 % (351/510), mild-to-moderate immunodeficiency (MID) patients accounted for 16.7 % (85/510), and severe immunodeficiency (SID) patients accounted for 14.5 % (74/510). PC patients in the MID and SID groups had a higher incidence of central nervous system (CNS) involvement than that in the IC group [4.7 % (MID) vs. 8.1 % (SID) vs. 1.1 % (IC), p = 0.002]. Patients with fever in SID group (35.1 %, 26/74) was more common (p < 0.01). Solitary nodule/mass were more common in the IC group than the MID and SID groups (p < 0.05); in contrast, diffuse nodules in MID or SID groups was significantly greater than that in IC groups (p < 0.01). The follow-up showed that the overall treatment improvement rate for PC showed a significant difference between the 3 groups [90.3 % (IC) vs. 75.3 % (MID) vs. 54.1 % (SID), p = 0.00]., Conclusion: The incidence of PC is increasing in Central China, especially for the immunocompetent PC population. In addition, there are significant differences in age, systemic symptoms, certain radiographic characteristics and some laboratory results between immunosuppressed and immunocompetent PC hosts. And finally, limited nodules/masses and mild symptoms in patients with PC often lead to misdiagnosis and unnecessary pulmonary resection, but CrAg assay contributes to early noninvasive diagnosis., Competing Interests: Declaration of competing interest We declare that we have no financial and personal relationships with other people or organizations that can inappropriately influence our work, there is no professional or other personal interest of any nature or kind in any product, service and/or company that could be construed as influencing the position presented in, or the review of, the manuscript entitled, “Clinical characteristics and therapeutic analysis of pulmonary cryptococcosis patients with different immune statuses: A 10-year multicenter retrospective study in China”., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Sphingosine phosphate lyase insufficiency syndrome (SPLIS) is a genetic disease associated with renal, endocrine, neurological, skin and immune defects. SPLIS is caused by inactivating mutations in SGPL1, which encodes sphingosine phosphate lyase (SPL). SPL catalyzes the irreversible degradation of the bioactive sphingolipid sphingosine-1-phosphate (S1P), a key regulator of lymphocyte egress. The SPL reaction represents the only exit point of sphingolipid metabolism, and SPL insufficiency causes widespread sphingolipid derangements that could additionally contribute to immunodeficiency. Herein, we review SPLIS, the sphingolipid metabolic pathway, and various roles sphingolipids play in immunity. We then explore SPLIS-related immunodeficiency by analyzing data available in the published literature supplemented by medical record reviews in ten SPLIS children. We found 93% of evaluable SPLIS patients had documented evidence of immunodeficiency. Many of the remainder of cases were unevaluable due to lack of available immunological data. Most commonly, SPLIS patients exhibited lymphopenia and T cell-specific lymphopenia, consistent with the established role of the S1P/S1P1/SPL axis in lymphocyte egress. However, low B and NK cell counts, hypogammaglobulinemia, and opportunistic infections with bacterial, viral and fungal pathogens were observed. Diminished responses to childhood vaccinations were less frequently observed. Screening blood tests quantifying recent thymic emigrants identified some lymphopenic SPLIS patients in the newborn period. Lymphopenia has been reported to improve after cofactor supplementation in some SPLIS patients, indicating upregulation of SPL activity. A variety of treatments including immunoglobulin replacement, prophylactic antimicrobials and special preparation of blood products prior to transfusion have been employed in SPLIS. The diverse immune consequences in SPLIS patients suggest that aberrant S1P signaling may not fully explain the extent of immunodeficiency. Further study will be required to fully elucidate the complex mechanisms underlying SPLIS immunodeficiency and determine the most effective prophylaxis against infection., Competing Interests: Declaration of competing interest JDS is co-founder of Sphinxion Therapeutics Inc., which is developing gene therapy for individuals with SPLIS. JDS is an author on patent International Application Serial No. PCT/US2021/018613, “Adeno-Associated Viral (Aav)-Mediated SGPL1 Gene Therapy for Treatment of Sphingosine-1-Phosphate Lyase Insufficiency Syndrome (SPLIS)” published on 08/26/2021 and assigned publication number WO 2021/168140. All other authors declare no conflicts of interest., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

The presence of IgG anti-IgA in the serum of primary immunodeficiency (PID) patients has long been considered responsible for hypersensitivity (HS) to immunoglobulin preparations (IgPs), but this link is increasingly being questioned. The aim of this work was to describe the prevalence of IgG anti-IgA and its association with HS, and to explore a new pathophysiological hypothesis involving the complement system. We measured IgG anti-IgA, using a standardised commercial technique, in controls and PID patients, and compared our results to a systematic literature review. We measured complement activation in PID patients before and after IgP infusion, and in vitro after incubation of IgP with serum from controls and PID patients. IgG anti-IgA was detected in 6% (n = 2/32) of PID patients, 30% (n = 3/10) of selective IgA deficiency patients and 2% (n = 1/46) of healthy controls. In the literature and our study, 38 PID patients had IgG anti-IgA and HS to IgPs and 9 had IgG anti-IgA but good tolerance to IgPs. In our patients, we observed a constant complement activation after IgP infusion compared to baseline. In vitro, IgP induced significant complement activation with all sera from tested individuals. IgA immunisation is not rare in PID, higher in selective IgA deficiency, but may also occur in healthy controls. Our results question the clinical relevance and pathophysiological implication of IgG anti-IgA in the context of HS with IgPs. Complement activation-related pseudoallergy could explain the clinical characteristics and natural history of HS symptoms., Competing Interests: Declarations. Ethics Approval: In line with French recommendations, no ethical approval was requested for this non-interventional study (MR-004 reference methodology). The data and the patients’ sample collections were declared to the CNIL (DEC24-089). Consent to Participate: In line with the regulations laid down by the French National Data Protection Commission (CNIL) and international guidelines, written, informed consent was neither required nor requested for this non-interventional study. The patients received by mail an information letter about the study and a non-opposition notice, and had the opportunity to refuse their inclusion. Consent for Publication: No identifying individual participants’ data are included in this manuscript. Competing Interests: Guillaume Lefèvre has received honoraria for serving on the board and for participating in symposia from Takeda, LFB, Griffols, research support from LFB, Takeda, CSL Behring, Biotest, Octapharma. David Launay has received honoraria for board or symposia from Takeda, Biocryst, Astra-Zeneca and CSL Behring, and research support from CSL Behring, and Octapharma. Emmanuel Ledoult has received consulting and personal fees from Takeda, Grifols, GSK and Astra-Zeneca., (© 2024. The Author(s).)

This paper presents a comprehensive and updated overview of inborn errors of immunity (IEIs), focusing on the optimal treatment strategies. IEIs or primary immunodeficiencies (PIDs) are a heterogeneous group of approximately 500 disorders, classified into ten categories according to the affected component of the immune system. The clinical presentation varies, based on the type of the disorder and the patient's age. Early diagnosis is essential to prevent recurrent severe infections and potential organ damage. Treatment strategies, including hematopoietic stem cell transplantation, enzyme replacement therapy, thymus trans-plantation, or gene therapy, primarily focus to restore immune function. Emerging therapeutic approaches aiming to modify the immune response comprise small molecule inhibitors, biological therapies, and adoptive transfer of virus-specific T-cells. Given the complexity and diversity of PIDs, as well as evolving novel therapies, continuous education of the physicians on timely diagnosis and effective intervention, significantly improves patients' management and outcomes. CONCLUSION: Early diagnosis and individualized treatment plans are crucial for effectively managing IEIs. As treatment options evolve, ongoing education and the integration of new approaches are key to improving patient outcomes and quality of life.

Congenital athymia is a life-limiting disorder due to rare inborn errors of immunity causing impaired thymus organogenesis or abnormal thymic stromal cell development and function. Athymic infants have a T-lymphocyte-negative, B-lymphocyte-positive, natural killer cell-positive immunophenotype with profound T-lymphocyte deficiency and are susceptible to severe infections and autoimmunity. Patients variably display syndromic features. Expanding access to newborn screening for severe combined immunodeficiency and T lymphocytopenia and broad genetic testing, including next-generation sequencing technologies, increasingly facilitate their timely identification. The recommended first-line treatment is allogeneic thymus transplantation, which is a specialized procedure available in Europe and the United States. Outcomes for athymic patients are best with early diagnosis and thymus transplantation before the development of infectious and inflammatory complications. These guidelines on behalf of the European Society for Immunodeficiencies provide a comprehensive review for clinicians who manage patients with inborn thymic stromal cell defects; they offer clinical practice recommendations focused on the diagnosis, investigation, risk stratification, and management of congenital athymia with the aim of improving patient outcomes., Competing Interests: Disclosure statement A.Y.K. is supported by the Wellcome Trust (222096/Z/20/Z). F.D. is supported by an NIHR Academic Clinical Lectureship and an Academy for Medical Sciences Starter Grant. E.H. and E.G.D. are supported by a grant from the Great Ormond Street Hospital Children’s Charity. O.E.’s laboratory is supported by grants from the Swedish Research Council (2018-02752 and 2022-00781) and the Swedish state under an ALF agreement between the Swedish government and the county councils (ALFGBG-965795). A.V. is supported by a core grant from the Telethon Foundation. F.J.T.’s laboratory is supported in part by EU H2020 grant RECOMB (755170–(b)) and has received funding from the European UnionHorizon 2020 research and innovation program as well as from reNEW, the Novo Nordisk Foundation for Stem Cell Research (NNF21CC0073729). G.A. is supported by an MRC Programme Grant to GA (MR/T029765/a). and G.H. is supported by the Wellcome Trust (211944/Z/18/Z). Disclosure of potential conflict of interest: The authors declare that they have no relevant conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

This review of immunocompromised host pneumonia as the result of inborn errors of immunity (IEI) is organized by opportunistic pulmonary pathogen. The authors identify patients who warrant an evaluation for an IEI based on their clinical presentation. Their recommendations are guided by the immune defect(s) associated with each opportunistic pulmonary infection. Physicians without expertise in immunology may begin an evaluation for IEI using the guidance provided here. Comprehensive evaluation by an immunologist may also be warranted in many instances., Competing Interests: Disclosures The authors have nothing to disclose., (Published by Elsevier Inc.)

IKKα is a multifunctional serine/threonine kinase that controls various biological processes, either dependent on or independent of its kinase activity. However, the importance of the kinase function of IKKα in human physiology remains unknown since no biallelic variants disrupting its kinase activity have been reported. In this study, we present a homozygous germline missense variant in the kinase domain of IKKα, which is present in three children from two Turkish families. This variant, referred to as IKKα G167R , is in the activation segment of the kinase domain and affects the conserved (DF/LG) motif responsible for coordinating magnesium atoms for ATP binding. As a result, IKKα G167R abolishes the kinase activity of IKKα, leading to impaired activation of the non-canonical NF-κB pathway. Patients carrying IKKα G167R exhibit a range of immune system abnormalities, including the absence of secondary lymphoid organs, hypogammaglobulinemia and limited diversity of T and B cell receptors with evidence of autoreactivity. Overall, our findings indicate that, unlike a nonsense IKKα variant that results in early embryonic lethality in humans, the deficiency of IKKα's kinase activity is compatible with human life. However, it significantly disrupts the homeostasis of the immune system, underscoring the essential and non-redundant kinase function of IKKα in humans., Competing Interests: Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Adult-onset immunodeficiency with antibodies to interferon-γ (AOID with AIGA) is a rare, acquired immunodeficiency causing susceptibility to disseminated non-tuberculous mycobacteria and other intracellular opportunistic infections. The diagnosis depends on demonstrating the presence of endogenous anti-interferon-γ antibodies (AIGA) that suppress Th1 cell-mediated immunity. Bioluminescent immunoassays are a newly emerging immunoassay format which utilize the action of bioluminescent enzymes on a substrate for specific analyte detection. In short, detecting antibodies are conjugated with a bioluminescent enzyme. The detecting antibodies bind the analyte of interest and produce light (luminescence) after addition of a substrate. The purpose of this study was to evaluate two newly developed bioluminescent immunoassays using Lumit® (Promega) technology as a diagnostic test for AOID with AIGA. Specific aims included the clinical validation of a new inhibition bioluminescent immunoassay technique to detect AIGA which block detection of interferon-γ (IFN-γ) in vitro and correlation of inhibition bioluminescent immunoassay results with AOID with AIGA disease status. Two bioluminescent inhibition immunoassays were developed. One which adapted an existing kit from Promega (Lumit® Human IFN-γ Immunoassay) and the other which was developed in house. Eighty-seven healthy controls and 48 patients with previously diagnosed AOID with AIGA were recruited and tested using these two methods. Results showed both bioluminescent inhibition immunoassays were able to clearly discriminate between AOID with AIGA patients and healthy controls. The mean inhibition percentage between patient groups correlated with disease activity. Both assays appeared to be more sensitive when compared to the existing inhibition ELISA., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Society for Immunology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background: Primary immunodeficiency diseases (inborn errors of immunity) with partial albinism are a group of autosomal recessive syndromes including Chediak Higashi Syndrome (CHS), Griscelli Syndrome type 2 (GS2), Hermansky-Pudlak Syndromes type 2 and 10 (HPS2, HPS10), Vici syndrome and P14/LAMTOR2 deficiency., Methods: Twenty-five patients including 10 CHS, 10 GS2, and 5 HPS2 were evaluated in this study within the last 10 years. Five cases with oculocutaneous albinism (OCA) and 5 healthy subjects without albinism were used as two control groups. Genetic analyses were performed by whole exome or panel sequencing or targeted Sanger sequencing. Subsequently, leukocyte granules in peripheral blood smear and hair shaft were examined as screening tests., Results: Giant granules were only presented in the leukocytes cytoplasm of 10/10 CHS patients. The uneven cluster of pigments and giant melanin granules in hair samples were observed in 10/10 GS2 and 10/10 CHS patients, respectively. In both 5/5 OCA and 5/5 HPS2 patients, there were regular pigments in the middle of hair shafts. Genetic analyses were performed for all patients, revealing 7 novel variants in LYST gene for CHS patients and 4 novel variants in AP3B1 for HPS2 patients., Conclusion: Receiving hematopoietic stem cell transplantation (HSCT) in a timely manner is crucial in CHS and GS2 patients; therefore, screening tests may provide a vital clue for early diagnosis in these patients. However, the final confirmation of CHS, GS2, and HPS2 disorders is done by genetic assay., (© 2024 European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)

Impaired immune response to COVID-19 (coronavirus disease 2019) vaccination has been reported in patients with inborn errors of immunity (IEI). Repetitive vaccinations are recommended for this vulnerable group. Due to the high diversity within IEI patients, additional safety and immunogenicity data are needed to better understand these aspects especially in less common immunodeficiency syndromes. In this prospective open-label clinical trial, we assessed the humoral immune response and the T‑cell response in patients with IEI or severe MBL (mannose-binding lectin) deficiency (IEI/MBLdef) after three vaccinations. A total of 16 patients and 16 matched healthy controls (HC) with suboptimal humoral response defined by anti-SARS-CoV‑2 RBD (severe acute respiratory syndrome coronavirus type 2 receptor binding domain) antibodies below 1500 BAU/ml (binding antibody units per ml) after the second COVID-19 vaccination were enrolled in this study and qualified for a third mRNA vaccine dose. After 4 weeks following vaccination, 100% of HC and 75% of IEI/MBLdef patients exhibited anti-SARS-CoV‑2 RBD antibodies > 1500 BAU/ml, although the difference was not statistically significant (75% vs. 100%; p = 0.109). Although post-vaccination IEI/MBLdef patients demonstrated significantly increased anti-SARS-CoV‑2 RBD antibodies and neutralizing antibodies compared to baseline, these responses were significantly lower in IEI/MBLdef patients compared to HCs. Notably, the third vaccination augmented the cellular immune response to both wild-type and omicron peptide stimulation. No serious adverse events were reported within the 4‑week follow-up period and, importantly, vaccination had little to no effect on the long-term disease activity and fatigue. This trial strongly supports the recommendation of repeated COVID-19 vaccinations for patients suffering from immunodeficiencies, especially when they exhibit an initially limited response to the vaccine., (© 2024. The Author(s).)

The function of the immune system is highly dependent on cellular differentiation and clonal expansion of antigen-specific lymphocytes. Telomeres are conserved DNA-protein structures of linear chromosome termini. Telomere length has been investigated to be different in various lymphocyte subpopulations depending on their function and to change with aging. Association of accelerated telomere loss compared to matched controls has already been confirmed in many syndromes with immune dysregulation. Immunodeficiencies connected with dysfunction of telomere termini are dyskeratosis congenita, ICF syndrome (Immunodeficiency, centromeric instability and facial anomalies syndrome) genetic disorders involving DNA repair and disorders involving the VDJ recombination., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 American Society for Histocompatibility and Immunogenetics. Published by Elsevier Inc. All rights reserved.)

Enteric viruses are the main cause of acute gastroenteritis worldwide with a significant morbidity and mortality, especially among children and aged adults. Some enteric viruses also cause disseminated infections and severe neurological manifestations such as poliomyelitis. Protective immunity against these viruses is not well understood in humans, with most knowledge coming from animal models, although the development of poliovirus and rotavirus vaccines has extended our knowledge. In a classical view, innate immunity involves the recognition of foreign DNA or RNA by pathogen recognition receptors leading to the production of interferons and other inflammatory cytokines. Antigen uptake and presentation to T cells and B cells then activate adaptive immunity and, in the case of the mucosal immunity, induce the secretion of dimeric IgA, the more potent immunoglobulins in viral neutralization. The study of Inborn errors of immunity (IEIs) offers a natural opportunity to study nonredundant immunity toward pathogens. In the case of enteric viruses, patients with a defective production of antibodies are at risk of developing neurological complications. Moreover, a recent description of patients with low or absent antibody production with protracted enteric viral infections associated with hepatitis reinforces the prominent role of B cells and immunoglobulins in the control of enteric virus., (© 2024 The Author(s). Immunological Reviews published by John Wiley & Sons Ltd.)

Over the last 15 years activity of diagnostic flow cytometry services have evolved from monitoring of CD4 T cell subsets in HIV-1 infection to screening for primary and secondary immune deficiencies syndromes and assessment of immune constitution following B cell depleting therapy and transplantation. Changes in laboratory activity in high income countries have been driven by initiation of anti-retroviral therapy (ART) in HIV-1 regardless of CD4 T cell counts, increasing recognition of primary immune deficiency syndromes and the wider application of B cell depleting therapy and transplantation in clinical practice. Laboratories should use their experience in standardization and quality assurance of CD4 T cell counting in HIV-1 infection to provide immune monitoring services to patients with primary and secondary immune deficiencies. Assessment of immune reconstitution post B cell depleting agents and transplantation can also draw on the expertise acquired by flow cytometry laboratories for detection of CD34 stem cell and assessment of MRD in hematological malignancies. This guideline provides recommendations for clinical laboratories on providing flow cytometry services in screening for immune deficiencies and its emerging role immune reconstitution after B cell targeting therapies and transplantation., (© 2024 The Author(s). Cytometry Part B: Clinical Cytometry published by Wiley Periodicals LLC on behalf of International Clinical Cytometry Society.)

While it is known that immunoglobulin replacement therapy (IgRT) used in the treatment of primary immunodeficiency disorders (PIDs) can lead to the passive transfer of autoantibodies, there is no data indicating that these antibodies can cause clinical symptoms in patients. This study aimed to investigate the presence of autoantibodies and their clinical correlation in patients diagnosed with PIDs receiving IgRT. Paediatric patients who were diagnosed with PIDs, and administered IgRT at our immunology clinic between 1 January 2012 and 31 December 2021, were included in the study. The medical records of these patients were retrospectively analysed, and autoantibodies were screened. Autoantibody screening was conducted at least once in 48 cases. Among these cases, 29 cases (60.4%) demonstrated positivity for at least one of the autoantibodies screened in the study. Among these cases, 23 tested positive for anti-TPO, 9 for anti-TG and 2 for both anti-TPO and anti-TG. Only two of these patients were confirmed to have Hashimoto's thyroiditis. In 30 cases, autoantibodies related to Celiac disease (CD) were screened, with at least one being positive in five different cases; CD was not confirmed. The results of our study suggest that passive transfer of autoantibodies to patients with IgRT does not cause any significant clinical findings. In addition, in cases of PID, autoantibodies detected in the blood passed to patients with IgRT can lead to misdiagnosis. Screening for autoantibodies in patients with PID undergoing IgRT may not yield accurate results in terms of detecting autoimmune diseases., (© 2024 The Scandinavian Foundation for Immunology.)

Primary immunodeficiency (PID) is no longer defined by infections alone, and autoimmunity is an accompanying manifestation of PID. Recurrent infections may trigger autoimmunity through molecular mimicry, bystander activation or superantigens. The diagnosis of PID is still challenging, but genetic analysis reveals the underlying link between PID and autoimmunity. Mutations in relevant genes affecting central and peripheral immune tolerance, regulatory T-cell function, expansion of autoreactive lymphocytes, antigen clearance, hyperactivation of type I interferon and nuclear factor-κB pathways have all been implicated in triggering autoimmunity in PID. Autoimmunity in PID leads to chronic inflammation, tissue damage and organ failure, and increases the mortality of patients with PID. The kidneys are inextricably linked with the immune system, and kidney diseases can be mediated by both infection and autoimmunity/inflammation in PID patients. The manifestations of kidney involvement in PID patients are very heterogeneous and include lupus nephritis, C3 glomerulopathy, kidney thrombotic microangiopathy, vasculitis and interstitial nephritis. Patients with PID-caused kidney diseases have defined immune function defects and may benefit from pathway-based biologics, stem cell transplantation or gene therapy. Early diagnosis and appropriate treatment of PID are crucial for reducing the mortality rate and improving organ function and quality of life., (© The Author(s) 2024. Published by Oxford University Press on behalf of the ERA.)

Purpose: Calculated globulin (CG, total protein minus albumin levels) correlate well with IgG levels and has been proposed as a suitable screening method for individuals with primary antibody deficiencies (PADs). We aimed to show the correlation of CG with IgG levels in children and adolescents, utilizing a common method for albumin measurement, bromocresol green., Methods: Individuals from two Allergy and Immunology clinics were invited to participate. Inclusion criteria were age < 18, stable conditions, and signed informed consent. We included 1084 individuals. Immunoglobulin G values were determined by immunoturbidimetry; the colorimetric bromocresol green method and the Architect Biuret method were utilized for the albumin and total protein (TP) measurements, respectively., Results: A total of 1084 individuals were included in the analysis and divided into 4 age groups (0 to <1 year, 1 to <4 years, 4 to <10 years, and 10 to <18 years). For all patients, the mean age was 6.1 (± 5) years old, the mean IgG was 9.4 (± 4.7) g/L, and CG was 23.7 (± 5.9) g/L. The most frequent diagnosis were respiratory allergies, followed by inborn errors of immunity. IgG and CG varied according to age group. Cutoff values for hypogammaglobulinemia varied from 13.8 g/L in children < 1 year to 23.1 g/L in children and adolescents aged 10 to <18 years. CG sensitivity varied from 70.9% in children aged 1 to <4 years old to 95.8% in children 4 to <10. Specificity ranged from 87.5% in children 4 to <10 years old to 100% in children and adolescents aged 10 to <18 years., Conclusion: CG is a suitable screening test for hypogammaglobulinemia in children less than 18 years of age., Competing Interests: AC-N declares receiving speaker’s fees and participating in advisory boards for Takeda, CSL Behring, Novartis, AstraZeneca, GSK, and Sanofi Genzyme and research funding from Takeda and CSL Behring. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Frias Sartorelli de Toledo Piza, Aranda, Solé, Jolles and Condino-Neto.)

Distinguishing between primary (PID) and secondary (SID) immunodeficiencies, particularly in relation to hematological B-cell lymphoproliferative disorders (B-CLPD), poses a major clinical challenge. We aimed to analyze and define the clinical and laboratory variables in SID patients associated with B-CLPD, identifying overlaps with late-onset PIDs, which could potentially improve diagnostic precision and prognostic assessment. We studied 37 clinical/laboratory variables in 151 SID patients with B-CLPD. Patients were classified as "Suspected PID Group" when having recurrent-severe infections prior to the B-CLPD and/or hypogammaglobulinemia according to key ESID criteria for PID. Bivariate association analyses showed significant statistical differences between "Suspected PID"- and "SID"-groups in 10 out of 37 variables analyzed, with "Suspected PID" showing higher frequencies of childhood recurrent-severe infections, family history of B-CLPD, significantly lower serum Free Light Chain (sFLC), immunoglobulin concentrations, lower total leukocyte, and switch-memory B-cell counts at baseline. Rpart machine learning algorithm was performed to potentially create a model to differentiate both groups. The model developed a decision tree with two major variables in order of relevance: sum κ + λ and history of severe-recurrent infections in childhood, with high sensitivity 89.5%, specificity 100%, and accuracy 91.8% for PID prediction. Identifying significant clinical and immunological variables can aid in the difficult task of recognizing late-onset PIDs among SID patients, emphasizing the value of a comprehensive immunological evaluation. The differences between "Suspected PID" and SID groups, highlight the need of early, tailored diagnostic and treatment strategies for personalized patient management and follow up., (© 2024. The Author(s).)

Early diagnosis of inborn errors of immunity (IEIs) has been shown to reduce mortality, morbidity, and healthcare costs. The need for early diagnosis has led to the development of computational tools that trigger earlier clinical suspicion by physicians. Primary care professionals serve as the first line for improving early diagnosis. To this end, a computer-based tool (based on extended Jeffrey Modell Foundation (JMF) Warning Signs) was developed to assist physicians with diagnosis decisions for IEIs in the primary care setting. Two expert-guided scoring systems (one pediatric, one adult) were developed. IEI warning signs were identified and a panel of 36 experts reached a consensus on which signs to include and how they should be weighted. The resulting scoring system was tested against a retrospective registry of patients with confirmed IEI using primary care EHRs. A pilot study to assess the feasibility of implementation in primary care was conducted. The scoring system includes 27 warning signs for pediatric patients and 24 for adults, adding additional clinically relevant criteria established by expert consensus to the JMF Warning Signs. Cytopenias, ≥ 2 systemic infections, recurrent fever and bronchiectasis were the leading warning signs in children, as bronchiectasis, autoimmune diseases, cytopenias, and > 3 pneumonias were in adults. The PIDCAP (Primary Immune Deficiency "Centre d'Atenció Primària" that stands for Primary Care Center in Catalan) tool was implemented in the primary care workstation in a pilot area. The expert-based approach has the potential to lessen under-reporting and minimize diagnostic delays of IEIs. It can be seamlessly integrated into clinical primary care workstations., (© 2024. The Author(s).)

Objectives: The development of External Quality Assessment Schemes (EQAS) for clinical flow cytometry (FCM) is challenging in the context of rare (immunological) diseases. Here, we introduce a novel EQAS monitoring the primary immunodeficiency Orientation Tube (PIDOT), developed by EuroFlow, in both a 'wet' and 'dry' format. This EQAS provides feedback on the quality of individual laboratories (i.e., accuracy, reproducibility and result interpretation), while eliminating the need for sample distribution., Methods: In the wet format, marker staining intensities (MedFIs) within landmark cell populations in PIDOT analysis performed on locally collected healthy control (HC) samples, were compared to EQAS targets. In the dry format, participants analyzed centrally distributed PIDOT flow cytometry data (n=10)., Results: We report the results of six EQAS rounds across 20 laboratories in 11 countries. The wet format (212 HC samples) demonstrated consistent technical performance among laboratories (median %rCV on MedFIs=34.5 %; average failure rate 17.3 %) and showed improvement upon repeated participation. The dry format demonstrated effective proficiency of participants in cell count enumeration (range %rCVs 3.1-7.1 % for the major lymphoid subsets), and in identifying lymphoid abnormalities (79.3 % alignment with reference)., Conclusions: The PIDOT-EQAS allows laboratories, adhering to the standardized EuroFlow approach, to monitor interlaboratory variations without the need for sample distribution, and provides them educational support to recognize rare clinically relevant immunophenotypic patterns of primary immunodeficiencies (PID). This EQAS contributes to quality improvement of PID diagnostics and can serve as an example for future flow cytometry EQAS in the context of rare diseases., (© 2024 Walter de Gruyter GmbH, Berlin/Boston.)

Prevention and treatment of infections are primary goals of treatment of children and adults with primary immune deficiencies due to decreased antibody production. Approaches to these goals include immunoglobulin replacement therapy, vaccination, and prophylactic treatment with antimicrobials. In this review, the infectious and non-infectious complications of antibody deficiencies will be discussed along with the limited number of studies that support the effective use of the available therapies and to drive the development of new therapies. Some illustrative case studies will be presented and the outlook for additional controlled clinical trials and potential for therapies driven by the underlying disease genetics will be considered., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Society for Immunology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Introduction: Congenital immunodeficiency is named primary immunodeficiency (PID), and more recently inborn errors of immunity (IEI). There are more than 485 conditions classified as IEI, with a wide spectrum of clinical and laboratory manifestations., Areas Covered: Regardless of the developing knowledge of IEI, many physicians do not think of IEI when approaching the patient's complaint, which leads to delayed diagnosis, misdiagnosis, serious infectious and noninfectious complications, permanent end-organ damage, and even death. Due to the various manifestations of IEI and the wide spectrum of associated conditions, patients refer to specialists in different disciplines of medicine and undergo - mainly symptomatic - treatments, and because IEI are not included in physicians' differential diagnosis, the main disease remains undiagnosed., Expert Opinion: A multidisciplinary approach may be a proper solution. Manifestations and the importance of a multidisciplinary approach in the diagnosis of main groups of IEI are discussed in this article.

High-throughput immune repertoire (IR) sequencing provides direct insight into the diversity of B cell receptor (BCR) and T cell receptor (TCR), with great potential to revolutionize the diagnosis, monitoring, and prevention of immune system-related disorders. In this study, multiplex PCR was applied to amplify the complementarity-determining regions of BCR and TCR, followed by comprehensive analysis by high-throughput sequencing. We compare the TCR (BCR) of bone marrow fluid (BMF) and peripheral blood (PB) samples from 17 patients in the Epstein-Barr and immunodeficiency groups, respectively. Our study shows that the diversity of the IR of blood samples is very similar to that of bone marrow samples statistically. However, the distributions of the monoclonal genes are significantly different in these 2 samples of most patients. This suggests that the BMFs can be replaced by the PB samples in diversity detection of IR to monitor the immune status of the body, while the detection of the BMFs is unreplaceable when the monoclonal change occurs. We used high-throughput sequencing to assess the TCR and BCR of the patients and provide a basis for the clinical analysis of PB and bone marrow samples and selection of disease diagnosis and monitoring methods., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

Immunoglobulins for intravenous use (IVIgs) and subcutaneous use (SCIgs) can prevent recurrent and severe infections in patients with secondary antibody deficiencies that are frequently linked to haematological/oncological malignancies as well as other clinical conditions and their respective treatments. Even so, as IVIgs and SCIgs are costly and their supply is limited, their clinical use must be optimised. The aim of this position paper is to provide structured practical guidance on the optimal use of IVIgs and SCIgs in secondary antibody deficiencies, particularly in haematological and oncological practice. The authors agree that the occurrence of severe infections is a prerequisite for the use of IVIgs. Serum IgG levels in general as well as IgG subclass levels can be additional indicators of whether a patient could benefit from IVIgs. Responsiveness to vaccines can help to identify immunodeficiency. Patients with chronic lymphocytic leukaemia or multiple myeloma who are receiving respective treatment, especially B-cell depletion therapy, but also some patients with autoimmune diseases are prone to antibody deficiencies and need IVIgs. For the optimal use of IVIgs and to maximise their potential benefit, the indication must be individually assessed for each patient. As a primary treatment goal, the authors define a sufficient prophylaxis of severe infections, which can be supported by normalising IgG levels. If the initiated treatment is insufficient or linked to intolerable adverse reactions, switching the product within the class of IVIgs or changing to a different batch of the same product can be considered. Pausing treatment can also be considered if there are no infections, which happens more frequently in summer, but treatment needs to be resumed once infections return. These structured recommendations for IVIg treatment in patients with secondary antibody deficiency may provide guidance for clinical practice and therefore help to allocate IVIgs to those who will benefit the most, without overusing valuable resources.

Warts, Hypogammaglobulinemia, Infections, and Myelokathexis (WHIM) syndrome is a rare primary immunodeficiency disease in humans caused by a gain of function in CXCR4, mostly due to inherited heterozygous mutations in CXCR4. One major clinical symptom of WHIM patients is their high susceptibility to human papillomavirus (HPV) induced disease, such as warts. Persistent high risk HPV infections cause 5% of all human cancers, including cervical, anogenital, head and neck and some skin cancers. WHIM mice bearing the same mutation identified in WHIM patients were created to study the underlying causes for the symptoms manifest in patients suffering from the WHIM syndrome. Using murine papillomavirus (MmuPV1) as an infection model in mice for HPV-induced disease, we demonstrate that WHIM mice are more susceptible to MmuPV1-induced warts (papillomas) compared to wild type mice. Namely, the incidence of papillomas is higher in WHIM mice compared to wild type mice when mice are exposed to low doses of MmuPV1. MmuPV1 infection facilitated both myeloid and lymphoid cell mobilization in the blood of wild type mice but not in WHIM mice. Higher incidence and larger size of papillomas in WHIM mice correlated with lower abundance of infiltrating T cells within the papillomas. Finally, we demonstrate that transplantation of bone marrow from wild type mice into WHIM mice normalized the incidence and size of papillomas, consistent with the WHIM mutation in hematopoietic cells contributing to higher susceptibility of WHIM mice to MmuPV1-induced disease. Our results provide evidence that MmuPV1 infection in WHIM mice is a powerful preclinical infectious model to investigate treatment options for alleviating papillomavirus infections in WHIM syndrome., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Wang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: Immunoglobulin G (IgG) subclass deficiencies and isolated IgA, IgM, IgE deficiencies have all been described in the literature with variable prevalence. Methods: These isotype deficiencies have a variable presentation from asymptomatic to recurrent infections resistant to prophylactic antibiotics. Results: Atopic disorders and autoimmune diseases are common comorbidities. IgE deficiency has been associated with impaired vaccine response and an increased risk of malignancy, particularly in patients with no allergic comorbidities and those with non-common variable immunodeficiency (CVID) humoral immunodeficiency, IgM deficiency, IgG2 deficiency, and CD4 lymphopenia. Conclusion: Close monitoring for malignancy should be strongly considered for these patients who are at risk. Treatment is variable and may include antimicrobial therapies for illnesses and prophylactic antibiotics in select patients, and immunoglobulin replacement can be considered for patients with refractory, recurrent infections.

Specific antibody deficiency (SAD) is a common primary immunodeficiency disorder that should be considered in older children and adults with recurrent and/or severe sinopulmonary infections. The diagnosis is characterized by inadequate antibody response to polysaccharide vaccine, specifically, pneumococcal, with normal responses to protein antigens and normal levels of serum immunoglobulins as well as immunoglobulin G (IgG) subclasses. The underlying mechanism for SAD is not completely elucidated. It is understood that young children have limited polysaccharide responsiveness, which develops with increased age. Due to this phenomenon, the consensus is that there is adequate immune maturity after age 2 years, which is the earliest for the SAD diagnosis to be established. There remains a lack of consensus on thresholds for polysaccharide nonresponse, and there are several commercial laboratories that measure a range of serotypes, with the recommendation for patients to have their diagnostic evaluation with serotype testing both before vaccination and after vaccination to be conducted by the same laboratory. Once a diagnosis has been made, the management of SAD is based on the clinical severity. Clinicians may consider prophylactic antibiotics as well as immunoglobulin replacement. These patients should be closely followed up, with the possibility of discontinuation of IgG replacement after 12 to 24 months. Children are more likely to demonstrate resolution of SAD than are adolescents and adults. Patients with SAD may also progress to a more severe immunodeficiency; therefore, continued monitoring remains a crucial principle of practice in the care of patients with SAD.

Juvenile Idiopathic Arthritis (JIA) is sometimes considered a diagnosis of exclusion as the name signifies that no cause is evident for this form of arthritis. Despite this JIA has some classical clinical features and many categories are defined based on the phenotype. Since there is no diagnostic test for JIA, diseases that can mimic JIA, including Primary Immunodeficiencies (PID) can sometimes be misdiagnosed as JIA. The clues to suspecting PIDs are early age of onset, presence of family history, increased susceptibility to infections, unusual features like urticaria, interstitial lung disease, sensorineural hearing loss and poor response to conventional therapy, amongst others. This review will highlight the basics of PIDs and will discuss PIDs that can present with arthritis and hence can be confused with JIA., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Autoimmune diseases constitute a broad, heterogenous group with many diverse and often overlapping symptoms. Even so, they are traditionally classified as either systemic, rheumatic diseases or organ-directed diseases. Several theories exist about autoimmune diseases, including defective self-recognition, altered self, molecular mimicry, bystander activation and epitope spreading. While there is no consensus about these theories, it is generally accepted that genetic, pre-disposing factors in combination with environmental factors can result in autoimmune disease. The relative contribution of genetic and environmental factors varies between diseases, as does the significance of individual contributing factors within related diseases. Among the genetic factors, molecules involved in antigen (Ag) recognition, processing, and presentation stand out (e.g., MHC I and II) together with molecules involved in immune signaling and regulation of cellular interactions (i.e., immuno-phenotypes). Also, various immuno-deficiencies have been linked to development of autoimmune diseases. Among the environmental factors, infections (e.g., viruses) have attracted most attention, but factors modulating the immune system have also been the subject of much research (e.g., sunlight and vitamin D). Multiple sclerosis currently stands out due to a very strong and proven association with Epstein-Barr virus infection, notably in cases of late infection and in cases of EBV-associated mononucleosis. Thus, a common picture is emerging that both systemic and organ-directed autoimmune diseases may appropriately be described as auto-immuno-deficiency syndromes (AIdeSs), a concept that emphasizes and integrates existing knowledge on the role of immuno-deficiencies and chronic infections with development of overlapping disease syndromes with variable frequencies of autoantibodies and/or autoreactive T cells. This review integrates and exemplifies current knowledge on the interplay of genetically determined immuno-phenotypes and chronic infections in the development of AIdeSs., Competing Interests: Declaration of competing interest None., (Copyright © 2024. Published by Elsevier B.V.)

There are approximately 500 congenital disorders that impair immune cell development and/or function. Patients with these disorders may present with a wide range of symptoms, including increased susceptibility to infection, autoimmunity, autoinflammation, lymphoproliferation, and/or atopy. Flow cytometry-based immune phenotyping of T and B lymphocytes plays an essential role in the evaluation of patients with these presentations. In this review, we describe the clinical utility of flow cytometry as part of a comprehensive evaluation of immune function and how this testing may be used as a diagnostic tool to identify underlying aberrant immune pathways, monitor disease activity, and assess infection risk., Competing Interests: Disclosure A. A. Nguyen is a staff physician at Boston Children’s Hospital and Instructor of Pediatrics at Harvard Medical School. C. D. Platt is a staff physician and Medical Director of Flow Cytometry at Boston Children’s Hospital, and Assistant Professor of Pediatrics at Harvard Medical School. The spouse of C. D. Platt is employed by Quest Diagnostics. A. A. Nguyen has nothing to disclose., (Copyright © 2024 Elsevier Inc. All rights reserved.)

The immune system is divided into two major branches: innate and adaptive. The innate immune system is the body's first line of defense and rapidly responds in a nonspecific manner to various microorganisms, foreign materials, or injuries. Phagocytes, which include macrophages, monocytes, and neutrophils, are innate immune cells that can surround and kill microorganisms, ingest foreign material, and remove dead cells. They also indirectly boost both innate and adaptive immune responses through various activation signals. Phagocytic defects characteristically lead to fungal and bacterial infections of the respiratory tract, lymph nodes, skin, and other organ systems, and they are commonly associated with inflammatory bowel disease. This primer will review high-yield innate defects of phagocytic cells, including defects of respiratory (oxidative) burst, defects of neutrophil migration, cyclic and severe congenital neutropenias and associated disorders, and other phagocyte defect disorders.

The primary immunodeficiency diseases are often accompanied by autoimmunity, autoinflammatory, or aberrant lymphoproliferation. The paradoxical nature of this association can be explained by the multiple cells and molecules involved in immune networks that interact with each other in synergistic, redundant, antagonistic, and parallel arrangements. Because progressively more immunodeficiencies are found to have a genetic etiology, in many cases, a monogenic pathology, an understanding of why immunodeficiency is really an immune dysfunction becomes evident. Understanding the role of specific genes allows us to better understand the complete nature of the inborn error of immunity (IEI); the latter is a term generally used when a clear genetic etiology can be discerned. Autoimmune cytopenias, inflammatory bowel disease, autoimmune thyroiditis, and autoimmune liver diseases as well as lymphomas and cancers frequently accompany primary immunodeficiencies, and it is important that the practitioner be aware of this association and to expect that this is more common than not. The treatment of autoimmune or immunodysregulation in primary immunodeficiencies often involves further immunosuppression, which places the patient at even greater risk of infection. Mitigating measures to prevent such an infection should be considered as part of the treatment regimen. Treatment of immunodysregulation should be mechanism based, as much as we understand the pathways that lead to the dysfunction. Focusing on abnormalities in specific cells or molecules, e.g., cytokines, will become increasingly used to provide a targeted approach to therapy, a prelude to the success of personalized medicine in the treatment of IEIs.

Background: LCP1 encodes L-plastin, an actin-bundling protein primarily expressed in hematopoietic cells. In mouse and fish models, LCP1 deficiency has been shown to result in hematologic and immune defects., Objective: This study aimed to determine the nature of a human inborn error of immunity resulting from a novel genetic variant of LCP1., Methods: We performed genetic, protein, and cellular analysis of PBMCs from a kindred with apparent autosomal dominant immune deficiency. We identified a candidate causal mutation in LCP1, which we evaluated by engineering the orthologous mutation in mice and Jurkat cells., Results: A splice-site variant in LCP1 segregated with lymphopenia, neutropenia, and thrombocytopenia. The splicing defect resulted in at least 2 aberrant transcripts, producing an in-frame deletion of 24 nucleotides, and a frameshift deletion of exon 8. Cellular analysis of the kindred revealed a proportionate reduction of T and B cells and a mild expansion of transitional B cells. Similarly, mice carrying the orthologous genetic variant exhibited the same in-frame aberrant transcript, reduced expression Lcp1 and gene dose-dependent leukopenia, mild thrombocytopenia, and lymphopenia, with a significant reduction of T-cell populations. Functional analysis revealed that LCP1 c740 - 1G>A confers a defect in platelet development and function with aberrant spreading on collagen. Immunologic analysis revealed defective actin organization in T cells, reduced migration of PBMCs from patients, splenocytes from mutant mice, and a mutant Jurkat cell line in response to CXCL12; impaired germinal center B-cell expansion after immunization; and reduced cytokinesis during T cell proliferation., Conclusions: We describe a unique human hematopoietic defect affecting neutrophils, lymphocytes, and platelets arising from partial LCP1 deficiency., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The complement system is an important component of innate and adaptive immunity that consists of three activation pathways. The classic complement pathway plays a role in humoral immunity, whereas the alternative and lectin pathways augment the innate response. Impairment, deficiency, or overactivation of any of the known 50 complement proteins may lead to increased susceptibility to infection with encapsulated organisms, autoimmunity, hereditary angioedema, or thrombosis, depending on the affected protein. Classic pathway defects result from deficiencies of complement proteins C1q, C1r, C1s, C2, and C4, and typically manifest with features of systemic lupus erythematosus and infections with encapsulated organisms. Alternative pathway defects due to deficiencies of factor B, factor D, and properdin may present with increased susceptibility to Neisseria infections. Lectin pathway defects, including Mannose-binding protein-associated serine protease 2 (MASP2) and ficolin 3, may be asymptomatic or lead to pyogenic infections and autoimmunity. Complement protein C3 is common to all pathways, deficiency of which predisposes patients to severe frequent infections and glomerulonephritis. Deficiencies in factor H and factor I, which regulate the alternative pathway, may lead to hemolytic uremic syndrome. Disseminated Neisseria infections result from terminal pathway defects (i.e., C5, C6, C7, C8, and C9). Diagnosis of complement deficiencies involves screening with functional assays (i.e., total complement activity [CH50], alternative complement pathway activity [AH50], enzyme-linked immunosorbent assay [ELISA]) followed by measurement of individual complement factors by immunoassay. Management of complement deficiencies requires a comprehensive and individualized approach with special attention to vaccination against encapsulated bacteria, consideration of prophylactic antibiotics, treatment of comorbid autoimmunity, and close surveillance.