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The International Union of Immunological Societies (IUIS) expert committee (EC) on Inborn Errors of Immunity (IEI) reports here the 2022 updated phenotypic classification, which accompanies and complements the most-recent genotypic classification. This phenotypic classification is aimed for clinicians at the bedside and focuses on clinical features and laboratory phenotypes of specific IEI. In this classification, 485 IEI underlying phenotypes as diverse as infection, malignancy, allergy, auto-immunity and auto-inflammation are described, including 55 novel monogenic defects and 1 autoimmune phenocopy. Therefore, all 485 diseases of the genetic classification are presented in this paper in the form of colored tables with essential clinical or immunological phenotype entries. [ABSTRACT FROM AUTHOR]

The presence of naturally occurring cytokine-specific autoantibodies (c-aAb) in humans is well established, as well as associations to selected pathologies. However, the overall influence of c-aAb on immunocompetence remains largely unknown. In this paper, we performed a large-scale investigation of c-aAb association with infection risk. A cohort of healthy Danish blood donors was screened for c-aAb against IL-1α, IL-6, IL-10, IFNα, and GM-CSF using a Luminex-based multiplex assay, and results were linked to data from the Danish National Prescription Registry. The filing of an antimicrobial prescription following c-aAb measurement was used as a proxy for impaired immunocompetence. We found that c-aAb against pro-inflammatory cytokines IFNα and GM-CSF tended to associate with increased risk of prescription filings in women, whereas antibodies against anti-inflammatory IL-10 were associated with a lower predicted risk of antimicrobial prescriptions, as well as higher self-perceived health scores. We also observed an association of cumulative c-aAb presence with prescription risk. Our data show that cytokine autoantibodies in healthy individuals associate with various proxies for immunomodulation, with the exact association dependent on the pattern of pro- or anti-inflammatory cytokines targeted. This suggests that c-aAb may express cytokine-modulatory properties in healthy individuals and may be critical to further investigate as biomarkers of immunodeficiency. [ABSTRACT FROM AUTHOR]

The JAK/STAT signaling pathway plays a key role in cytokine signaling and is involved in development, immunity, and tumorigenesis for nearly any cell. At first glance, the JAK/STAT signaling pathway appears to be straightforward. However, on closer examination, the factors influencing the JAK/STAT signaling activity, such as cytokine diversity, receptor profile, overlapping JAK and STAT specificity among non-redundant functions of the JAK/STAT complexes, positive regulators (e.g., cooperating transcription factors), and negative regulators (e.g., SOCS, PIAS, PTP), demonstrate the complexity of the pathway's architecture, which can be quickly disturbed by mutations. The JAK/STAT signaling pathway has been, and still is, subject of basic research and offers an enormous potential for the development of new methods of personalized medicine and thus the translation of basic molecular research into clinical practice beyond the use of JAK inhibitors. Gain-of-function and loss-of-function mutations in the three immunologically particularly relevant signal transducers STAT1, STAT3, and STAT6 as well as JAK1 and JAK3 present themselves through individual phenotypic clinical pictures. The established, traditional paradigm of loss-of-function mutations leading to immunodeficiency and gain-of-function mutation leading to autoimmunity breaks down and a more differentiated picture of disease patterns evolve. This review is intended to provide an overview of these specific syndromes from a clinical perspective and to summarize current findings on pathomechanism, symptoms, immunological features, and therapeutic options of STAT1, STAT3, STAT6, JAK1, and JAK3 loss-of-function and gain-of-function diseases. [ABSTRACT FROM AUTHOR]

Patient registries are a very important and essential tool for investigating rare diseases, as most physicians only see a limited number of cases during their career. Diseases of multi-organ autoimmunity and autoinflammation are especially challenging, as they are characterized by diverse clinical phenotypes and highly variable expressivity. The GAIN consortium (German multi-organ Auto Immunity Network) developed a dataset addressing these challenges. ICD-11, HPO, and ATC codes were incorporated to document various clinical manifestations and medications with a defined terminology. The GAIN dataset comprises detailed information on genetics, phenotypes, medication, and laboratory values. Between November 2019 and July 2022, twelve centers from Europe have registered 419 patients with multi-organ autoimmunity or autoinflammation. The median age at onset of symptoms was 13 years (IQR 3–28) and the median delay from onset to diagnosis was 5 years (IQR 1–14). Of 354 (84.5%) patients who were genetically tested, 248 (59.2%) had a defined monogenetic cause. For 87 (20.8%) patients, no mutation was found and for 19 (4.5%), the result was pending. The most common gene affected was NFkB1 (48, 11.5%), and the second common was CTLA4 (40, 9.5%), both genetic patient groups being fostered by specific research projects within GAIN. The GAIN registry may serve as a valuable resource for research in the inborn error of immunity community by providing a platform for etiological and diagnostic research projects, as well as observational trials on treatment options. [ABSTRACT FROM AUTHOR]

Cells of the innate and adaptive immune systems depend on proper actin dynamics to control cell behavior for effective immune responses. Dysregulated actin networks are known to play a pathogenic role in an increasing number of inborn errors of immunity. The WAVE regulatory complex (WRC) mediates branched actin polymerization, a process required for key cellular functions including migration, phagocytosis, vesicular transport, and immune synapse formation. Recent reports of pathogenic variants in NCKAP1L, a hematopoietically restricted gene encoding the HEM1 protein component of the WRC, defined a novel disease involving recurrent bacterial and viral infections, autoimmunity, and excessive inflammation (OMIM 141180). This review summarizes the diverse clinical presentations and immunological phenotypes observed in HEM1-deficient patients. In addition, we integrate the pathophysiological mechanisms described in current literature and highlight the outstanding questions for diagnosis and management of the HEM1 actin immunodysregulatory disorder. [ABSTRACT FROM AUTHOR]

Purpose: Knowledge of post-hematopoietic cell transplantation (HCT) non-hematological autoimmune disease (AD) is far from satisfactory. Method: This multicenter retrospective study focuses on incidence, risk factors, and outcomes of post-HCT AD in 596 children with primary immunodeficiency (PID) who were transplanted from 2009 to 2018. Results: The indications of HCT were severe combined immunodeficiency (SCID, n = 158, 27%) and non-SCID PID (n = 438, 73%). The median age at HCT was 2.3 years (range, 0.04 to 18.3 years). The 5-year overall survival for the entire cohort was 79% (95% cumulative incidence (CIN), 74–83%). The median follow-up of surviving patients was 4.3 years (0.08 to 14.7 years). The CIN of post-HCT AD was 3% (2–5%) at 1 year post-HCT, 7% (5–11%) at 5 years post-HCT, and 11% (7–17%) at 8 years post-HCT. The median onset of post-HCT AD was 2.2 years (0.12 to 9.6 years). Autoimmune thyroid disorder (n = 19, 62%) was the most common post-HCT AD, followed by neuromuscular disorders (n = 7, 22%) and rheumatological manifestations (n = 5, 16%). All patients but one required treatment for post-HCT AD. After multivariate analysis, age at transplant (p = 0.01) and T cell–depleted graft (p < 0.001) were significant predictors of post-HCT AD. None of the T cell–depleted graft recipients developed post-HCT AD. Patients with a lower CD3+ count at 6 months post-HCT had a significant higher incidence of post-HCT AD compared to disease controls. Graft-versus-host disease, viral infection, and donor chimerism had no association with post-HCT AD. Conclusion: Post-HCT AD occurred in 11% at 8 years post-HCT and its occurrence was associated with older age at HCT and unmanipulated graft. [ABSTRACT FROM AUTHOR]

Purpose: DiGeorge syndrome has substantial heterogeneity with variable immune deficiency and dysregulation. Implicated immunopathology includes reduced thymic output and increased peripheral homeostatic proliferation with Th2 skewing and expansion of self-reactive cells. We hypothesized that T cell lymphopenia severity will be associated with higher odds of autoimmunity and/or asthma. Methods: Using the US Immunodeficiency Network registry, we identified patients with 22q11.2 deletion (and/or TBX1). Initial absolute CD3+ T cell values were stratified: normal, 50–99% and below 50% of the lower limit of age-adjusted normal values. Patients with and without reported autoimmunity and asthma were compared using chi-square tests and multivariate logistic regression. Results: Among 415 patients, autoimmunity was reported in 17 (4.1%), and asthma was reported in 28 (6.7%). Compared with those with no reported autoimmunity, patients with reported autoimmunity more frequently had low CD19+ B cells [3.3% (12/364) vs 28.6% (4/14); p = 0.002] and low IgG [6.2% (20/321) vs 29.4% (5/17); p = 0.005] levels. There were no statistically significant differences in other immune characteristics among those with and without reported asthma. Patients with absolute CD3 levels below 50% of age-adjusted normal values had higher odds of reported autoimmunity (n = 319, OR = 7.56, 95% CI = 1.58–36.17, p = 0.01) and reported asthma (n = 319, OR = 4.5, 95% CI = 1.06–18.93, p = 0.04) as compared with those with normal CD3 values, adjusted for age and low IgG. Conclusions: Absolute CD3+ T cell counts below 50% of age-adjusted normal values may be associated with higher odds of autoimmunity and/or asthma in patients with DiGeorge syndrome and be potentially useful to identify higher-risk patients. [ABSTRACT FROM AUTHOR]

MALT1 (mucosa-associated lymphoid tissue lymphoma-translocation gene 1) is an intracellular signaling protein that activates NFκB and is crucial for both the adaptive and innate immune responses. Only 6 patients with immune deficiencies secondary to inherited mutations in the MALT1 gene have been described. Purpose: To provide clinical and immunological insights from 2 patients diagnosed with MALT1 immunodeficiency syndrome due to a novel MALT1 mutation. Methods: Two cousins with suspected combined immunodeficiency underwent immunological and genetic work-up, including lymphocyte phenotyping, lymphocyte activation by mitogen stimulation, and next-generation sequencing (NGS) of T cell receptor gamma chain (TRG) repertoire. Whole exome sequencing was performed to identify the underlying genetic defect. Results: Clinical findings included recurrent infections, failure to thrive, lymphadenopathy, dermatitis, and autoimmunity. Immune work-up revealed lymphocytosis, low to normal levels of immunoglobulins, absence of regulatory T cells, and low Th17 cells. A normal proliferative response was induced by phytohemagglutinin and IL-2 but was diminished with anti-CD3. TRG repertoire was diverse with a clonal expansion pattern. Genetic analysis identified a novel autosomal recessive homozygous c.1799T>A; p. I600N missense mutation in MALT1. MALT1 protein expression was markedly reduced, and in vitro IL-2 production and NFκB signaling pathway were significantly impaired. Conclusions: Two patients harboring a novel MALT1 mutation presented with signs of immune deficiency and dysregulation and were found to have an abnormal T cell receptor repertoire. These findings reinforce the link between MALT1 deficiency and combined immunodeficiency. Early diagnosis is crucial, and curative treatment by hematopoietic stem cell transplantation may be warranted. [ABSTRACT FROM AUTHOR]

Purpose: Primary selective IgM deficiency (sIgMD) is a primary immunodeficiency with unclear pathogenesis and a low number of published cases. Methods: We reviewed clinical and laboratory manifestations of 17 sIgMD patients. Serum IgM, IgG, and its subclasses, IgA, IgE, antibodies against tetanus toxoid, pneumococcal polysaccharides and Haemophilus influenzae type b, isohemagglutinins, and T and B lymphocyte subsets, expressions of IgM on B cells and B lymphocyte production of IgM were compared with previously reported case reports and a small series of patients, which included 81 subjects in total. Results: We found that some patients in our cohort (OC) and published cases (PC) had increased IgE levels (OC 7/15; PC 21/37), decreased IgG4 levels (OC 5/14), very low titers of isohemagglutinins (OC 8/8; PC 18/21), increased transitional B cell counts (OC 8/9), decreased marginal zone B cell counts (OC 8/9), and increased 21 B cell counts (OC 7/9). Compared with the PC (20/20), only two of five OC patients showed very low or undetectable production of IgM after stimulation. A majority of the patients had normal antibody production to protein and polysaccharide antigens, basic lymphocyte subset counts, and expression of surface IgM molecules on B cells. Conclusions: Low IgM levels are associated with various immunopathological disorders; however, pathogenic mechanisms leading to decreased IgM serum level in selective IgM deficiency remain unclear. Moreover, it is difficult to elucidate how strong these associations are and if these immunopathological conditions are primary or secondary. [ABSTRACT FROM AUTHOR]

To date, several germline mutations have been identified in the LRBA gene in patients suffering from a variety of clinical symptoms. These mutations abolish the expression of the LRBA protein, leading to autoimmunity, chronic diarrhea, B-cell deficiency, hypogammaglobulinemia, functional T-cell defects and aberrant autophagy. We review the clinical and laboratory features of patients with LRBA mutations and present five novel mutations in eight patients suffering from a multitude of clinical features. [ABSTRACT FROM AUTHOR]

Purpose: Autoimmune lymphoproliferative syndrome (ALPS) is a non-malignant genetic disorder of lymphocyte homeostasis with defective Fas-mediated apoptosis. Current therapies for ALPS primarily target autoimmune manifestations with non-specific immune suppressants with variable success thus highlighting the need for better therapeutics for this disorder. Methods: The spectrum of clinical manifestations of ALPS is mirrored by MRL/lpr mice that carry a loss of function mutation in the Fas gene and have proven to be a valuable model in predicting the efficacy of several therapeutics that are front-line modalities for the treatment of ALPS. We evaluated the potential efficacy of tofacitinib, an orally active, pan-JAK inhibitor currently approved for rheumatoid arthritis as a single agent modality against ALPS using MRL/lpr mice. Results: We demonstrate that a 42-day course of tofacitinib therapy leads to a lasting reversal of lymphadenopathy and autoimmune manifestations in the treated MRL/lpr mice, Specifically, in treated mice the peripheral blood white blood cell counts were reversed to near normal levels with almost a 50 % reduction in the TCRαβCD4CD8T lymphocyte numbers that coincided with a parallel increase in CD8 T cells without a demonstrable effect on CD4 lymphocytes including FoxP3 regulatory T cells. The elevated plasma IgG and IgA levels were also drastically lowered along with a significant reduction in plasmablasts and plasmacytes in the spleen. Conclusion: On the basis of these results, it is likely that tofacitinib would prove to be a potent single agent therapeutic modality capable of ameliorating both offending lymphadenopathy as well as autoimmunity in ALPS patients. [ABSTRACT FROM AUTHOR]

Background: Recombination-activating gene (RAG) 1 and 2 deficiency is seen in patients with severe combined immunodeficiency (SCID) and Omenn syndrome. However, the spectrum of the disease has recently expanded to include a milder phenotype. Objective: We analyzed a 4-year-old boy who was initially given the diagnosis of selective immunoglobulin A deficiency (SIgAD) based on immunoglobulin serum levels without any opportunistic infections, rashes, hepatosplenomegaly, autoimmunity or granulomas. The patient was found to be infected with varicella zoster; however, the clinical course was not serious. He produced antiviral antibodies. Methods: We performed lymphocyte phenotyping, quantification of T cell receptor excision circles (TRECs) and kappa deleting recombination excision circles (KRECs), an analysis of target sequences of RAG1 and 2, a whole-genome SNP array, an in vitro V(D)J recombination assay, a spectratype analysis of the CDR3 region and a flow cytometric analysis of the bone marrow. Results: Lymphocyte phenotyping demonstrated that the ratio of CD4+ to CD8+ T cells was inverted and the majority of CD4+T cells expressed CD45RO antigens in addition to the almost complete lack of B cells. Furthermore, both TRECs and KRECs were absent. Targeted DNA sequencing and SNP array revealed that the patient carried a deletion of RAG1 and RAG2 genes on the paternally-derived chromosome 11, and two maternally-derived novel RAG1 missense mutations (E455K, R764H). In vitro analysis of recombination activity showed that both RAG1 mutant proteins had low, but residual function. Conclusions: The current case further expands the phenotypic spectrum of mild presentations of RAG deficiency, and suggests that TRECs and KRECs are useful markers for detecting hidden severe, as well as mild, cases. [ABSTRACT FROM AUTHOR]