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BACKGROUND: In 2014, germline signal transducer and activator of transcription (STAT) 3 gain-of-function (GOF) mutations were first described to cause a novel multisystem disease of early-onset lymphoproliferation and autoimmunity. OBJECTIVE: This pivotal cohort study defines the scope, natural history, treatment, and overall survival of a large global cohort of patients with pathogenic STAT3 GOF variants. METHODS: We identified 191 patients from 33 countries with 72 unique mutations. Inclusion criteria included symptoms of immune dysregulation and a biochemically confirmed germline heterozygous GOF variant in STAT3. RESULTS: Overall survival was 88%, median age at onset of symptoms was 2.3 years, and median age at diagnosis was 12 years. Immune dysregulatory features were present in all patients: lymphoproliferation was the most common manifestation (73%); increased frequencies of double-negative (CD4-CD8-) T cells were found in 83% of patients tested. Autoimmune cytopenias were the second most common clinical manifestation (67%), followed by growth delay, enteropathy, skin disease, pulmonary disease, endocrinopathy, arthritis, autoimmune hepatitis, neurologic disease, vasculopathy, renal disease, and malignancy. Infections were reported in 72% of the cohort. A cellular and humoral immunodeficiency was observed in 37% and 51% of patients, respectively. Clinical symptoms dramatically improved in patients treated with JAK inhibitors, while a variety of other immunomodulatory treatment modalities were less efficacious. Thus far, 23 patients have undergone bone marrow transplantation, with a 62% survival rate. CONCLUSION: STAT3 GOF patients present with a wide array of immune-mediated disease including lymphoproliferation, autoimmune cytopenias, and multisystem autoimmunity. Patient care tends to be siloed, without a clear treatment strategy. Thus, early identification and prompt treatment implementation are lifesaving for STAT3 GOF syndrome.

Clinical data from ADA-SCID patients registered in the U.S. Immunodeficiency Network (USIDNet) Repository were analyzed. Sixty-four ADA-SCID patients born between 1981 and 2017 had clinical data entered by their local (or home) enrolling institution. Median age at diagnosis was 1 month for those with a positive family history and 3 months for those without a prior family history, with some diagnosed at birth and one as late as 9 years of age. Overall survival was 79.7%, which increased to 94.1% since 2010. These patients had multiple infections and pulmonary, gastrointestinal, and neurological complications. The majority received enzyme replacement therapy (ERT) at some time, including 88% of those born since 2010. Twenty-six patients underwent allogeneic hematopoietic stem cell transplant (HSCT). HSCT successfully supported survival (17/26, 65%) using a variety of cell sources (bone marrow, mobilized peripheral blood, and cord blood) from sibling, family and unrelated donors. Nineteen patients underwent autologous HSCT with gene therapy (GT) using retroviral and lentiviral vectors and all are surviving. The prognosis for patients with ADA-SCID has continued to improve but these patients do have multiple early and potentially long-term conditions that require medical monitoring and management.

BackgroundAutosomal dominant hyper-IgE syndrome (AD-HIES) is a rare condition.ObjectiveData from the USIDNET Registry provide a resource to examine the characteristics of patients with rare immune deficiency diseases.MethodsA query was submitted to the USIDNET requesting deidentified data for patients with physician-diagnosed AD-HIES through July 2016.ResultsData on 85 patients diagnosed with AD-HIES (50 males; 35 females) born between 1950 and 2013, collected by 14 physicians from 25 states and Quebec, were entered into the USIDNET Registry by July 2016. Cumulative follow-up was 2157 years. Of these patients, 45.9% had a family history of HIES. The complications reported included skin abscesses (74.4%), eczema (57.7%), retained primary teeth (41.4%), fractures (39%), scoliosis (34.1%), and cancer (7%). Reported allergic diseases included food (37.8%), environmental (18%), and drugs (42.7%). The mean serum IgE level was 8383.7 kU/mL and was inversely correlated to the patient's age. A total of 49.4% had eosinophilia; 56% were known to be on trimethoprim-sulfamethoxazole, 26.6% on antifungal coverage, and 30.6% on immunoglobulin replacement therapy. Pneumonias were more commonly attributed to Staphylococcus aureus (55.3%) or Aspergillus fumigatus (22.4%); 19.5% had a history of lung abscess; these were most often associated with Pseudomonas aeruginosa (P Fisher's exact test = .029) or A. fumigatus (P Fisher's exact test = .016). Lung abscesses were significantly associated with drug reactions (P χ2 = .01; odds ratio: 4.03 [1.2-12.97]), depression (P Fisher's exact test = .036), and lower Karnofsky index scores (P Mann-Whitney = .007).DiscussionData from the USIDNET Registry summarize the currently reported clinical characteristics of a large cohort of subjects with AD-HIES.

We describe five cases of children who completed chemotherapy for infantile acute lymphoblastic leukemia (ALL) and soon after were diagnosed with severe T-cell, non-HIV immunodeficiency, with varying B-cell and NK-cell depletion. There was near absence of CD3(+) , CD4(+) , and CD8(+) cells. All patients developed multiple, primarily opportunistic infections. Unfortunately, four patients died, although one was successfully treated by hematopoietic stem cell transplantation. These immunodeficiencies appeared to be secondary to intensive infant ALL chemotherapy. Our report highlights the importance of the early consideration of this life-threatening immune complication in patients who received chemotherapy for infantile ALL.

In patients with 18q deletion syndrome (18q‐), immunodeficiency, autoimmunity, and allergies have been described in a subset. Pitt–Hopkins syndrome represents a specific subset of patients with 18q‐ who have a proximal deletion involving the TCF4 gene or a TCF4 variant. Immunodeficiency has been reported in the overall 18q‐ population; however, immunodeficiency with Pitt‐Hopkins syndrome has not been highlighted. This case report details the immunologic evaluations and the associated infections seen in a young adult with Pitt–Hopkins syndrome to underscore the challenges of managing adults with a complex phenotype who develop frequent infections. This patient with Pitt–Hopkins syndrome ultimately fulfilled the diagnostic criteria for common variable immunodeficiency. Immunoglobulin replacement has led to a somewhat improved infection pattern, although she continues to have aspiration events leading to pneumonia. This case highlights the clinical evolution of Pitt–Hopkins syndrome and serves as a reminder that immunodeficiency can occur in this syndrome. [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]

This guideline aims to describe the complement system and the functions of the constituent pathways, with particular focus on primary immunodeficiencies (PIDs) and their diagnosis and management. The complement system is a crucial part of the innate immune system, with multiple membrane-bound and soluble components. There are three distinct enzymatic cascade pathways within the complement system, the classical, alternative and lectin pathways, which converge with the cleavage of central C3. Complement deficiencies account for ~5% of PIDs. The clinical consequences of inherited defects in the complement system are protean and include increased susceptibility to infection, autoimmune diseases (e.g., systemic lupus erythematosus), age-related macular degeneration, renal disorders (e.g., atypical hemolytic uremic syndrome) and angioedema. Modern complement analysis allows an in-depth insight into the functional and molecular basis of nearly all complement deficiencies. However, therapeutic options remain relatively limited for the majority of complement deficiencies with the exception of hereditary angioedema and inhibition of an overactivated complement system in regulation defects. Current management strategies for complement disorders associated with infection include education, family testing, vaccinations, antibiotics and emergency planning. [ABSTRACT FROM AUTHOR]

Purpose: Granulomas are a potentially severe condition that can last for several years in persons with primary immunodeficiency disorders (PIDD). We assessed the prevalence of granulomas in patients with PIDD.Methods: We used the Truven Health MarketScan® 2005-2015 Commercial Claims and Encounters and 2006-2015 Medicaid databases and the US Immunodeficiency Network (USIDNET) PIDD registry (a program of the Immune Deficiency Foundation). Our study population consisted of persons age < 65 years with PIDD, defined as persons with ≥ 2 claims with a diagnostic code for PIDD in MarketScan databases, or patients enrolled in USIDNET. Granulomas were identified using diagnostic codes in MarketScan or provider report in USIDNET. We calculated annual prevalence of PIDD and of granulomas among PIDD patients.Results: We identified 247,474 and 40,395 persons with PIDD among commercially and Medicaid-insured persons, respectively. PIDD prevalence was 6.0/10,000 in 2005 and 11.7/10,000 in 2015 among commercially insured persons and 5.5/10,000 in 2006 and 9.6/10,000 in 2015 among Medicaid-insured persons. The prevalence of granulomas among PIDD patients was 1.2 and 1.5% among commercially and Medicaid-insured persons, respectively. In USIDNET, prevalence of granulomas was 4.4% (177/4021). The proportion with granulomas was similar across age groups in MarketScan, but varied from 2 to 9% in USIDNET. The reported prevalence of granulomas differed depending on PIDD condition: 1-2% in the MarketScan data and 0-13% in USIDNET.Conclusion: Granuloma prevalence in PIDD patients was 1-4%. Our study provides an estimate of the proportion of PIDD patients and suggests that granulomas are an uncommon occurrence among patients with PIDD. [ABSTRACT FROM AUTHOR]

Purpose: The point prevalence of underweight status and obesity in primary immunodeficiency disease (PID) is unknown, despite the described associations between PID and weight loss and failure to thrive. The goal of this study is to estimate the prevalence of underweight status and obesity in PID patients and to investigate the associations between abnormal body weight and complications of PID.Methods: Using the US Immunodeficiency Network (USIDNET), we performed a retrospective analysis of 653 pediatric (age 2 to 20 years) and 514 adult (age > 20) patient records with information on patient body mass index (BMI). Prevalence of underweight and obese status in PID patients was compared to data from the National Health and Nutrition Examination Survey (NHANES).Results: After separating BMI data by year of entry to the database, we demonstrated that both adult and pediatric patients with PID had significantly higher prevalence of underweight patients in multiple years of analysis. Further examination of underweight patients by PID diagnosis revealed that underweight status in adults with CVID was associated with granulomatous disease as well as earlier age of CVID diagnosis. In the pediatric CVID cohort, underweight status was significantly associated with lymphopenia. Examination of obesity in pediatric and adult PID patients compared to NHANES database revealed only a single year when obesity in PID patients was significantly less prevalent. In other 2-year time intervals from 2005 to 2014, the prevalence of obesity was unchanged in children and adults.Conclusions: These results quantify the prevalence of underweight status in PID in a North American population and demonstrate that whether as a result of weight loss or poor weight gain, underweight status is more prevalent in the PID population than in the general US population. The prevalence of obesity in PID patients was similar to that seen in the general population. This highlights the need for continued education on the association of low weight and PID.Clinical Trial Registration: NCT01953016 [ABSTRACT FROM AUTHOR]

Although small prior studies have suggested that IgE can be low in common variable immunodeficiency (CVID), the workup for patients with recurrent infections and suspected hypogammaglobulinemia does not include the routine measurement of serum IgE. We sought to test the hypothesis that low/undetectable serum IgE is characteristic of CVID by comparing the frequency of low/undetectable serum IgE in healthy controls and patients with CVID. We measured total serum IgE in a large multi-center cohort of patients with CVID (n = 354) and compared this to large population-based cohorts of children and adults. We further compared IgE levels in patients with CVID to those with other forms of humoral immunodeficiency, and in a subset, measured levels of allergen-specific serum IgE and IgG subclasses. Lastly, we evaluated for the presence of IgE in commercially available immunoglobulin replacement therapy (IgRT) products. An undetectable serum IgE (< 2 IU/ml) occurs in only 3.3% (95% CI, 1.9-5.7%) of the general population. In contrast, an undetectable IgE occurs in 75.6% (95% CI, 65.6-85.7%) of patients with CVID. Conversely, a high IgE (> 180 IU/ml) is very uncommon in CVID (0.3% of patients). IgE is > 2 IU/ml in 91.2% of patients with secondary hypogammaglobulinemia, and thus, an IgE < LLOD is suggestive of a primary humoral immunodeficiency. Allergen-specific IgE is not detectable in 96.5% of patients with CVID. Sufficient quantities of IgE to change the total serum IgE are not contained in IgRT. The IgG1/IgG4 ratio is increased in subjects with low IgE, regardless of whether they are controls or have CVID. These findings support the routine measurement of serum IgE in the workup of patients with hypogammaglobulinemia. [ABSTRACT FROM AUTHOR]

Common variable immunodeficiency (CVID) is increasingly recognized for its association with autoimmune and inflammatory complications. Despite recent advances in immunophenotypic and genetic discovery, clinical care of CVID remains limited by our inability to accurately model risk for non-infectious disease development. Herein, we demonstrate the utility of unbiased network clustering as a novel method to analyze inter-relationships between non-infectious disease outcomes in CVID using databases at the United States Immunodeficiency Network (USIDNET), the centralized immunodeficiency registry of the United States, and Partners, a tertiary care network in Boston, MA, USA, with a shared electronic medical record amenable to natural language processing. Immunophenotypes were comparable in terms of native antibody deficiencies, low titer response to pneumococcus, and B cell maturation arrest. However, recorded non-infectious disease outcomes were more substantial in the Partners cohort across the spectrum of lymphoproliferation, cytopenias, autoimmunity, atopy, and malignancy. Using unbiased network clustering to analyze 34 non-infectious disease outcomes in the Partners cohort, we further identified unique patterns of lymphoproliferative (two clusters), autoimmune (two clusters), and atopic (one cluster) disease that were defined as CVID non-infectious endotypes according to discrete and non-overlapping immunophenotypes. Markers were both previously described {high serum IgE in the atopic cluster [odds ratio (OR) 6.5] and low class-switched memory B cells in the total lymphoproliferative cluster (OR 9.2)} and novel [low serum C3 in the total lymphoproliferative cluster (OR 5.1)]. Mortality risk in the Partners cohort was significantly associated with individual non-infectious disease outcomes as well as lymphoproliferative cluster 2, specifically (OR 5.9). In contrast, unbiased network clustering failed to associate known comorbidities in the adult USIDNET cohort. Together, these data suggest that unbiased network clustering can be used in CVID to redefine non-infectious disease inter-relationships; however, applicability may be limited to datasets well annotated through mechanisms such as natural language processing. The lymphoproliferative, autoimmune, and atopic Partners CVID endotypes herein described can be used moving forward to streamline genetic and biomarker discovery and to facilitate early screening and intervention in CVID patients at highest risk for autoimmune and inflammatory progression. [ABSTRACT FROM AUTHOR]

Beginning in 1970, a committee was constituted under the auspices of the World Health Organization (WHO) to catalog primary immunodeficiencies. Twenty years later, the International Union of Immunological Societies (IUIS) took the remit of this committee. The current report details the categorization and listing of 354 (as of February 2017) inborn errors of immunity. The growth and increasing complexity of the field have been impressive, encompassing an increasing variety of conditions, and the classification described here will serve as a critical reference for immunologists and researchers worldwide. [ABSTRACT FROM AUTHOR]

Background The 22q11.2 deletion syndrome is a variably expressed disorder that can include cardiac, palate, and other physical abnormalities, immunodeficiency, and hypocalcemia. Because of the extreme variability in phenotype, there has been no available estimate of the total medical expenditure associated with the average case. Methods We have developed a model to estimate the cost from the time of diagnosis to age 20. Costs were based on patients seen at a specialty center but also considered those components of care expected to have been provided by external healthcare facilities. Expense was based on billed medical charges extracted from the electronic medical billing system for all patients with a diagnosis of DiGeorge or velocardiofacial syndrome from 1993-2015. Expenditures included maternal prenatal care directly related to an affected pregnancy, molecular/cytogenetic diagnosis, consultations, surgery, and/or other treatment and management. Most mental health services (except inpatient), therapy related to cognitive, behavioral, speech, pharmacy, and nonmedical costs (special education, vocational, respite, lost earnings) were not included. Results Data were available for 642 patients with 50.7% diagnosed prenatally or in the first year of life. The average cost for a patient was $727,178. Costs were highest for patients ascertained prenatally ($2,599,955) or in the first year of life ($1,043,096), those with cardiac abnormalities or referred for cardiac evaluation ($751,535), and patients with low T-cell counts ($1,382,222). Conclusion This study demonstrates that there are significant medical costs associated with 22q11.2 deletion syndrome. [ABSTRACT FROM AUTHOR]

In today's global economy and affordable vacation travel, it is increasingly important that visitors to another country and their physician be familiar with emerging infections, infections unique to a specific geographic region, and risks related to the process of travel. This is never more important than for patients with primary immunodeficiency disorders (PIDD). A recent review addressing common causes of fever in travelers provides important information for the general population Thwaites and Day (N Engl J Med 376:548-560, 2017). This review covers critical infectious and management concerns specifically related to travel for patients with PIDD. This review will discuss the context of the changing landscape of infections, highlight specific infections of concern, and profile distinct infection phenotypes in patients who are immune compromised. The organization of this review will address the environment driving emerging infections and several concerns unique to patients with PIDD. The first section addresses general considerations, the second section profiles specific infections organized according to mechanism of transmission, and the third section focuses on unique phenotypes and unique susceptibilities in patients with PIDDs. This review does not address most parasitic diseases. Reference tables provide easily accessible information on a broader range of infections than is described in the text. [ABSTRACT FROM AUTHOR]

Purpose: Common variable immunodeficiency (CVID) is a complex, heterogeneous immunodeficiency characterized by hypogammaglobulinemia, recurrent infections, and poor antibody response to vaccination. While antibiotics and immunoglobulin prophylaxis have significantly reduced infectious complications, non-infectious complications of autoimmunity, inflammatory lung disease, enteropathy, and malignancy remain of great concern. Previous studies have suggested that CVID patients diagnosed in childhood are more severely affected by these complications than adults diagnosed later in life. We sought to discern whether the rates of various infectious and non-infectious conditions differed between pediatric-diagnosed (ages 17 or younger) versus adult-diagnosed CVID (ages 18 or older). Methods: Using the United States Immunodeficiency Network (USIDNET) database, we performed a retrospective analysis of 457 children and adults with CVID, stratified by age at diagnosis. Chi-squared testing was used to compare pediatric versus adult groups. Results: After correcting for multiple comparisons, we identified few statistically significant differences ( p ≤ 0.0004) between pediatric and adult groups. Pediatric-onset CVID patients had more frequent diagnoses of otitis media, developmental delay, and failure to thrive compared with adult-onset CVID patients. Adult CVID patients were more frequently diagnosed with bronchitis, arthritis, depression, and fatigue. Diagnoses of autoimmunity, lymphoma, and other malignancies were higher in adults but not to a significant degree. Serum immunoglobulins (IgG, IgA, and IgM) and lymphocyte subsets did not differ significantly between the two groups. When complications of infections and co-morbid conditions were viewed categorically, there were few differences between pediatric-onset and adult-onset CVID patients. Conclusions: These results suggest that pediatric CVID is not a distinct phenotype. Major features were comparable across the groups. This study underscores the need for continued longitudinal study of pediatric and early-onset CVID patients to further characterize accrual of features over time. [ABSTRACT FROM AUTHOR]

Purpose: Chromosome 22q11.2 deletion syndrome (22q11.2DS), the most common cause of DiGeorge syndrome, is quite variable. Neonatal diagnosis traditionally relies on recognition of classic features and cytogenetic testing, but many patients come to attention only following identification of later onset conditions, such as hypernasal speech due to palatal insufficiency and developmental and behavioral differences including speech delay, autism, and learning disabilities that would benefit from early interventions. Newborn screening (NBS) for severe combined immunodeficiency (SCID) is now identifying infants with 22q11.2DS due to T cell lymphopenia. Here, we report findings in such neonates, underscoring the efficacy of early diagnosis. Methods: A retrospective chart review of 1350 patients with 22q11.2DS evaluated at the Children's Hospital of Philadelphia identified 11 newborns with a positive NBS for SCID. Results: Five out of 11 would have been diagnosed with 22q11.2DS without NBS, whereas early identification of 22q11.2DS in 6/11 led to the diagnosis of significant associated features including hypocalcemia, congenital heart disease (CHD), and gastroesophageal reflux disease that may have gone unrecognized and therefore untreated. Conclusions: Our findings support rapidly screening infants with a positive NBS for SCID, but without SCID, for 22q11.2DS even when typically associated features such as CHD are absent, particularly when B cells and NK cells are normal. Moreover, direct NBS for 22q11.2DS using multiplex qPCR would be equally, if not more, beneficial, as early identification of 22q11.2DS will obviate a protracted diagnostic odyssey while providing an opportunity for timely assessment and interventions as needed, even in the absence of T cell lymphopenia. [ABSTRACT FROM AUTHOR]

Viral infections are commonplace and often innocuous. Nevertheless, within the population of patients with primary immunodeficiencies (PIDDs), viral infections can be the feature that drives a diagnostic evaluation or can be the most significant morbidity for the patient. This review is focused on the viral complications of PIDDs. It will focus on respiratory viruses, the most common type of viral infection in the general population. Children and adults with an increased frequency or severity of respiratory viral infections are often referred for an immunologic evaluation. The classic teaching is to investigate humoral function in people with recurrent sinopulmonary infections, but this is often interpreted to mean recurrent bacterial infections. Recurrent or very severe viral infections may also be a harbinger of a primary immunodeficiency as well. This review will also cover persistent cutaneous viral infections, systemic infections, central nervous system infections, and gastrointestinal infections. In each case, the specific viral infections may drive a diagnostic evaluation that is specific for that type of virus. This review also discusses the management of these infections, which can become problematic in patients with PIDDs. [ABSTRACT FROM AUTHOR]

Newborn screening for SCID has revealed the association of low T cells with a number of unexpected syndromes associated with low T cells, some of which were not appreciated to have this feature. This review will discuss diagnostic approaches and the features of some of the syndromes likely to be encountered following newborn screening for immune deficiencies. [ABSTRACT FROM AUTHOR]

Purpose: The United States Immunodeficiency Network (USIDNET) patient registry was used to characterize the presentation, genetics, phenotypes, and treatment of patients with Hyper IgM Syndrome (HIGM). Methods: The USIDNET Registry was queried for HIGM patient data collected from October 1992 to July 2015. Data fields included demographics, criteria for diagnosis, pedigree analysis, mutations, clinical features, treatment and transplant records, laboratory findings, and mortality. Results: Fifty-two physicians entered data from 145 patients of ages 2 months to 62 years (median 12 years); 131 were males. Using patients' age at last entry, data from 2072 patient years are included. Mutations were recorded for 85 subjects; 82 were in CD40LG. Eighteen subjects had non-X-linked HIGM. 40 % had a normal serum IgM and 15 %, normal IgA. Infections were reported for 91 %, with pulmonary, ear, and sinus infections being the most common. 42 % had Pneumocystis jirovecii pneumonia; 6 % had Cryptosporidium. 41 % had neutropenia. 78 % experienced non-infectious complications: chronic diarrhea ( n = 22), aphthous ulcers ( n = 28), and neoplasms ( n = 8) including colon cancer, adrenal adenoma, liver adenocarcinoma, pancreatic carcinoid, acute myeloid leukemia, hepatoma, and, in a female with an autosomal dominant gain of function mutation in PIK3CD, an ovarian dysgerminoma. Thirteen patients had a hematopoietic marrow or stem cell transplant; three had solid organ transplants. Thirteen were known to have died (median age = 14 years). Conclusions: Analysis of the USIDNET Registry provides data on the common clinical features of this rare syndrome, and in contrast with previously published data, demonstrates longer survival times and reduced gastrointestinal manifestations. [ABSTRACT FROM AUTHOR]

We report the updated classification of primary immunodeficiencies compiled by the Primary Immunodeficiency Expert Committee (PID EC) of the International Union of Immunological Societies (IUIS). In the two years since the previous version, 34 new gene defects are reported in this updated version. For each disorder, the key clinical and laboratory features are provided. In this new version we continue to see the increasing overlap between immunodeficiency, as manifested by infection and/or malignancy, and immune dysregulation, as manifested by auto-inflammation, auto-immunity, and/or allergy. There is also an increased number of genetic defects that lead to susceptibility to specific organisms which reflects the finely tuned nature of immune defense systems. This classification is the most up to date catalogue of all known and published primary immunodeficiencies and acts as a current reference of the knowledge of these conditions and is an important aid for the genetic and molecular diagnosis of patients with these rare diseases. [ABSTRACT FROM AUTHOR]

There are now nearly 300 single-gene inborn errors of immunity underlying phenotypes as diverse as infection, malignancy, allergy, auto-immunity, and auto-inflammation. For each of these five categories, a growing variety of phenotypes are ascribed to Primary Immunodeficiency Diseases (PID), making PIDs a rapidly expanding field of medicine. The International Union of Immunological Societies (IUIS) PID expert committee (EC) has published every other year a classification of these disorders into tables, defined by shared pathogenesis and/or clinical consequences. In 2013, the IUIS committee also proposed a more user-friendly, phenotypic classification, based on the selection of key phenotypes at the bedside. We herein propose the revised figures, based on the accompanying 2015 IUIS PID EC classification. [ABSTRACT FROM AUTHOR]

Background Common variable immunodeficiency (CVID) is characterized clinically by inadequate quantity and quality of serum immunoglobulins with increased susceptibility to infections, resulting in significant morbidity and mortality. Only a few genes have been uncovered, and the genetic background of CVID remains elusive to date for the majority of patients. Objective We sought to seek novel associations of genes and genetic variants with CVID. Methods We performed association analyses in a discovery cohort of 164 patients with CVID and 19,542 healthy control subjects genotyped on the Immuno BeadChip from Illumina platform; replication of findings was examined in an independent cohort of 135 patients with CVID and 2,066 healthy control subjects, followed by meta-analysis. Results We identified 11 single nucleotide polymorphisms (SNPs) at the 16p11.2 locus associated with CVID at a genome-wide significant level in the discovery cohort. The most significant SNP, rs929867 ( P = 6.21 × 10 −9 ), is in the gene fused-in-sarcoma (FUS) , with 4 other SNPs mapping to integrin CD11b (ITGAM) . Results were confirmed in our replication cohort. Conditional association analysis suggests a single association signal at the 16p11.2 locus. A strong trend of association was also seen for 38 SNPs ( P < 5 × 10 −5 ) in the MHC region, supporting that this is a genuine CVID locus. Interestingly, we found that 80% of patients with the rare ITGAM variants have reduced switched memory B-cell counts. Conclusion We report a novel association of CVID with rare variants at the FUS/ITGAM (CD11b) locus on 16p11.2. The association signal is enriched for promoter/enhancer markers in the ITGAM gene. ITGAM encodes the integrin CD11b, a part of complement receptor 3, a novel candidate gene implicated here for the first time in the pathogenesis of CVID. [ABSTRACT FROM AUTHOR]

Objectives: Information about patients with primary immune deficiencies can be scarce because of the rarity of the disorders. Individual centers rarely have sufficient patients to educate trainees and garner collective wisdom. Registries for many diseases have proven their worth by providing essential information on disease spectrum, treatments and natural history. This study describes the construction and use of a registry for patients with primary immune deficiencies and other efforts to improve knowledge and care for affected patients and their families. Methods: Registry demographics and data were extracted using proprietary reporting tools. Educational efforts and cell repository data were collected from centralized source material. Results: The USIDNET Registry contains 3,459 patients, with common variable immune deficiency being the most represented. Pilot studies identified strengths and weaknesses of the data. Visiting Professor and Visiting Scholar Programs have been successful, encouraging trainees at all levels to pursue a career in Immunology. Conclusions: USIDNET's comprehensive and integrated approach provides resources that strengthen the field of primary immune deficiencies, as shown by utilization by 312 distinct sites or individuals. The reach of USIDNET's efforts is extended through the educational resources. [ABSTRACT FROM AUTHOR]

Primary immunodeficiencies are intrinsic defects in the immune system that result in a predisposition to infection and are frequently accompanied by a propensity to autoimmunity and/or immunedysregulation. Primary immunodeficiencies can be divided into innate immunodeficiencies, phagocytic deficiencies, complement deficiencies, disorders of T cells and B cells (combined immunodeficiencies), antibody deficiencies and immunodeficiencies associated with syndromes. Diseases of immune dysregulation and autoinflammatory disorder are many times also included although the immunodeficiency in these disorders are often secondary to the autoimmunity or immune dysregulation and/or secondary immunosuppression used to control these disorders. Congenital primary immunodeficiencies typically manifest early in life although delayed onset are increasingly recognized. The early diagnosis of congenital immunodeficiencies is essential for optimal management and improved outcomes. In this International Consensus (ICON) document, we provide the salient features of the most common congenital immunodeficiencies. [ABSTRACT FROM AUTHOR]

Background: Dedicator of cytokinesis 8 (DOCK8) mutations are responsible for a rare primary combined immunodeficiency syndrome associated with severe cutaneous viral infections, increased IgE levels, autoimmunity, and malignancy. Natural killer (NK) cells are essential for tumor surveillance and defense against virally infected cells. NK cell function relies on Wiskott-Aldrich syndrome protein for filamentous actin (F-actin) accumulation at the lytic NK cell immunologic synapse. DOCK8 activates cell division cycle 42, which, together with Wiskott-Aldrich syndrome protein, coordinates F-actin reorganization. Although abnormalities in T- and B-cell function have been described in DOCK8-deficient patients, the role of NK cells in this disease is unclear. Objectives: We sought to understand the role of DOCK8 in NK cell function to determine whether NK cell abnormalities explain the pathogenesis of the clinical syndrome of DOCK8 deficiency. Methods: A cohort of DOCK8-deficient patients was assembled, and patients'' NK cells, as well as NK cell lines with stably reduced DOCK8 expression, were studied. NK cell cytotoxicity, F-actin content, and lytic immunologic synapse formation were measured. Results: DOCK8-deficient patients'' NK cells and DOCK8 knockdown cell lines all had decreased NK cell cytotoxicity, which could not be restored after IL-2 stimulation. Importantly, DOCK8 deficiency impaired F-actin accumulation at the lytic immunologic synapse without affecting overall NK cell F-actin content. Conclusions: DOCK8 deficiency results in severely impaired NK cell function because of an inability to form a mature lytic immunologic synapse through targeted synaptic F-actin accumulation. This defect might underlie and explain important attributes of the DOCK8 deficiency clinical syndrome, including the unusual susceptibility to viral infection and malignancy. [Copyright &y& Elsevier]

Background 22q11.2 deletion syndrome (22q11.2DS) is the most common microdeletion disorder, affecting an estimated 1 : 2000-4000 live births. Patients with 22q11.2DS have a broad spectrum of phenotypic abnormalities which generally includes congenital cardiac abnormalities, palatal anomalies, and immunodeficiency. Additional findings, such as skeletal anomalies and autoimmune disorders, can confer significant morbidity in a subset of patients. 22q11.2DS is a contiguous gene DS and over 40 genes are deleted in patients; thus deletion of several genes within this region contributes to the clinical features. Mutations outside or on the remaining 22q11.2 allele are also known to modify the phenotype. Methods We utilised whole exome, targeted exome and/or Sanger sequencing to examine the genome of 17 patients with 22q11.2 deletions and phenotypic features found in <10% of affected individuals. Results and conclusions In four unrelated patients, we identified three novel mutations in SNAP29, the gene implicated in the autosomal recessive condition cerebral dysgenesis, neuropathy, ichthyosis and keratoderma (CEDNIK). SNAP29 maps to 22q11.2 and encodes a soluble SNARE protein that is predicted to mediate vesicle fusion at the endoplasmic reticulum or Golgi membranes. This work confirms that the phenotypic variability observed in a subset of patients with 22q11.2DS is due to mutations on the non-deleted chromosome, which leads to unmasking of autosomal recessive conditions such as CEDNIK, Kousseff, and a potentially autosomal recessive form of Opitz G/BBB syndrome. Furthermore, our work implicates SNAP29 as a major modifier of variable expressivity in 22q11.2 DS patients. [ABSTRACT FROM AUTHOR]

Recent studies suggest that patients with common variable immunodeficiency (CVID) and low numbers of switched memory B cells have lower IgG levels and higher rates of autoimmune disease, splenomegaly, and granulomatous disease; however, no prior literature has focused exclusively on pediatric cases. We examined the relationship between switched memory B cells and clinical and immunologic manifestations of CVID in a pediatric population. Forty-five patients were evaluated. Patients were categorized as Group I (<5 switched memory B cells/ml, n = 24) or Group II (⩾5 switched memory B cells/mL, n = 21). CD3+ T-cell counts and CD19+ B-cell levels were lower among Group I patients. Only those in Group I had meningitis, sepsis, bronchiectasis, granulomatous lung disease, autoimmune cytopenias, or hematologic malignancies. Segregation of pediatric patients into high risk (Group I) and average risk (Group II) may assist in targeting surveillance appropriately. [ABSTRACT FROM AUTHOR]

Background: Although fever is considered a sign of infection, many individuals with primary immunodeficiency (PI) anecdotally report a lower-than-normal average body temperature on online forums sponsored by the Immune Deficiency Foundation (IDF). There is limited knowledge about the average body temperature and fever response in PI. Objective: This study aims to compare median body temperatures between adults with and without PI diagnoses living in the same household and to engage individuals living with PI throughout the research process. Methods: Patients with PI designed and launched a prospective cohort comparison study as citizen scientists. A multidisciplinary team designed and implemented a patient-informed study with continuous patient-driven input. Median body temperatures were compared between the 2 cohorts using the Mann-Whitney test with Bonferroni correction. The IDF conducted a post-study patient experience survey. Results: Data from 254 households were analyzed (254/350, 72.6% participation rate). The PI population was predominantly female (218/254, 85.8%), White (248/254, 97.6%), and with a median age of 49 years. The non-PI population was largely male (170/254, 66.9%), White (236/254, 92.9%), and with a median age of 53 years. Common variable immunodeficiency was the most common PI diagnosis (190/254, 74.8%). Of the 254 individuals with PI, 123 (48.4%) reported a lower-than-normal nonsick body temperature, whereas 108 (42.5%) reported a normal (between 97°F and 99°F) nonsick body temperature. Among individuals with PI, when infected, 67.7% (172/254) reported the absence of fever, whereas 19.7% (50/254) reported a normal fever response. The recorded median body temperature was minimally but statistically significantly higher for patients with PI in the morning. Although 22.4% (57/254) of patients with PI self-reported illness, a fever of 100.4°F or higher was uncommon; 77.2% (196/254) had a normal temperature (between 97°F and 99°F), and 16.2% (41/254) had a lower-than-normal temperature (between 95.0°F and 96.9°F) when sick. For these sick patients with PI, the median body temperature was minimally but statistically significantly higher for patients in the morning and early evening. Overall, 90.9% (231/254) of participants would be very likely to participate in future IDF studies, although 94.1% (239/254) participants had never taken part in previous studies. Conclusions: To our knowledge, this is the first study to evaluate average body temperature in individuals with PI. Although there were small statistically significant differences in body temperatures between PI and non-PI subjects, the clinical significance is unclear and should be interpreted with caution, given the methodological issues associated with our small convenience sample and study design. As PIs are heterogeneous, more research is needed about how the fever response differs among diverse PIs compared with healthy controls. This study highlights that individuals with PI are knowledgeable about their health and can offer unique insights and direction to researchers and clinicians. J Participat Med 2020;12(4):e22297 doi:10.2196/22297 [ABSTRACT FROM AUTHOR]

Comments on the article "Primary Immunodeficiencies," by Megan A. Cooper, Thomas L. Pommering and Katalin Korányi. Review of some advancements in the diagnosis of primary immunodeficiencies; Importance of timely diagnosis of antibody defects; Need for recognition of patients with T-cell deficiencies.

Presents an abstract of the study `Defective Natural Killer (NK) Cell Activation in X-Linked Lymphoproliferative Disease,' by L. Benoit, X. Wang, H.F. Pabst, J. Dutz and R. Tan., published in a 2000 issue of the `Journal of Immunology.'

Background: Common variable immunodeficiency (CVID) is a heterogeneous immune defect characterized by hypogammaglobulinemia, failure of specific antibody production, susceptibility to infections, and an array of comorbidities. Objective: To address the underlying immunopathogenesis of CVID and comorbidities, we conducted the first genome-wide association and gene copy number variation (CNV) study in patients with CVID. Methods: Three hundred sixty-three patients with CVID from 4 study sites were genotyped with 610,000 single nucleotide polymorphisms (SNPs). Patients were divided into a discovery cohort of 179 cases in comparison with 1,917 control subjects and a replication cohort of 109 cases and 1,114 control subjects. Results: Our analyses detected strong association with the MHC region and association with a disintegrin and metalloproteinase (ADAM) genes (P combined = 1.96 × 10−7) replicated in the independent cohort. CNV analysis defined 16 disease-associated deletions and duplications, including duplication of origin recognition complex 4L (ORC4L) that was unique to 15 cases (P = 8.66 × 10−16), as well as numerous unique rare intraexonic deletions and duplications suggesting multiple novel genetic causes of CVID. Furthermore, the 1,000 most significant SNPs were strongly predictive of the CVID phenotype by using a Support Vector Machine algorithm with positive and negative predictive values of 1.0 and 0.957, respectively. Conclusion: Our integrative genome-wide analysis of SNP genotypes and CNVs has uncovered multiple novel susceptibility loci for CVID, both common and rare, which is consistent with the highly heterogeneous nature of CVID. These results provide new mechanistic insights into immunopathogenesis based on these unique genetic variations and might allow for improved diagnosis of CVID based on accurate prediction of the CVID clinical phenotypes by using our Support Vector Machine model. [ABSTRACT FROM AUTHOR]

Presents an abstract of the study 'Mutation in the Class II Trans-Activator Leading to a Mild Immunodeficiency,' by W. Wiszniewski, M-C Fondaneche, F. Le Deist, et al., from a 2001 issue of the 'Journal of Immunology.'

Presents an abstract of the study 'A Deletion in the Gene Encoding the CD45 Antigen in a Patient With SCID,' by E.Z. Tchilan, D.L. Wallace, R.S. Wells, D.R. Flower, G. Morgan and P.C.L. Beverly, from a 2001 issue of the 'Journal of Immunology.'

Presents an abstract of the study `Upregulation of Interleukin-12 in Monocytes: A Fundamental Defect in Common Variable Immunodefiency,' by R. Cambronero, W.A. Sewell, M.E. North, A.D. Webster and J. Farrant, published in a 2000 issue of the `Journal of Immunology.'

Presents an abstract of the study titled `Immunohistologic Analysis of Ineffective CD40-CD40 Ligand Interaction in Lymphoid Tissues From Patients with X-Linked Immunodeficiency with Hyper-IgM,' by F. Facchetti, C. Appiani, published in the 154th volume 1995 issue of `J. Immunol.'

The Primary Immune Deficiency Treatment Consortium (PIDTC) performed a retrospective analysis of 662 patients with severe combined immunodeficiency (SCID) who received a hematopoietic cell transplantation (HCT) as first-line treatment between 1982 and 2012 in 33 North American institutions. Overall survival was higher after HCT from matched-sibling donors (MSDs). Among recipients of non-MSD HCT, multivariate analysis showed that the SCID genotype strongly influenced survival and immune reconstitution. Overall survival was similar for patients with RAG, IL2RG, or JAK3 defects and was significantly better compared with patients with ADA or DCLRE1C mutations. Patients with RAG or DCLRE1C mutations had poorer immune reconstitution than other genotypes. Although survival did not correlate with the type of conditioning regimen, recipients of reduced-intensity or myeloablative conditioning had a lower incidence of treatment failure and better T- and B-cell reconstitution, but a higher risk for graft-versus-host disease, compared with those receiving no conditioning or immunosuppression only. Infection-free status and younger age at HCT were associated with improved survival. Typical SCID, leaky SCID, and Omenn syndrome had similar outcomes. Landmark analysis identified CD4+ and CD4+CD45RA+ cell counts at 6 and 12 months post-HCT as biomarkers predictive of overall survival and long-term T-cell reconstitution. Our data emphasize the need for patient-tailored treatment strategies depending upon the underlying SCID genotype. The prognostic significance of CD4+ cell counts as early as 6 months after HCT emphasizes the importance of close follow-up of immune reconstitution to identify patients who may need additional intervention to prevent poor long-term outcome. [ABSTRACT FROM AUTHOR]

Persistent rubella virus (RV) infection has been associated with various pathologies such as congenital rubella syndrome, Fuchs's uveitis, and cutaneous granulomas in patients with primary immune deficiencies (PID). Currently there are no drugs to treat RV infections. Nitazoxanide (NTZ) is an FDA-approved drug for parasitic infections, and has been recently shown to have broad-spectrum antiviral activities. Here we found that empiric 2-month therapy with oral NTZ was associated in the decline/elimination of RV antigen from lesions in a PID patient with RV positive granulomas, while peginterferon treatment had no effect. In addition, we characterized the effects of NTZ on cell culture models of persistent RV infection. NTZ significantly inhibited RV replication in a primary culture of human umbilical vein endothelial cells (HUVEC) and Vero and A549 epithelial cell lines in a dose dependent manner with an average 50% inhibitory concentration of 0.35 μg/ml (1.1 μM). RV strains representing currently circulating genotypes were inhibited to a similar extent. NTZ affected early and late stages of infection by inhibiting synthesis of cellular and RV RNA and interfering with intracellular trafficking of the RV surface glycoproteins, E1 and E2. These results suggest a potential application of NTZ for the treatment of persistent rubella infections, but more studies are required. [ABSTRACT FROM AUTHOR]

Chromosome 22q11.2 deletion syndrome is a common immune deficiency associated with thymic hypoplasia. Most patients did not survive until the mid-1980s and now there is a growing adult population. B cell and immunoglobulin defects have been described and appear to be increased in the adult population. We used flow cytometry, B cell stimulation and repertoire analysis to understand B cell function. B cell production at early stages appeared to be normal in patients but adult patients exhibited a deficit of switched memory B cells. Follicular helper T cells were present at higher percentages in patients and they exhibited a more activated phenotype in patients compared to controls. In spite of that, somatic hypermutation was decreased in patients compared to controls at all ages. Fewer mutations per clone were seen, strongly implicating aberrant T cell help. Therefore, patients with chromosome 22q11.2 deletion syndrome have a progressive decrease in switched memory B cells and evidence of compromised T cell help. In children, evidence of compromised T cell help is limited to decreased somatic hypermutation. With age, greater manifestations become apparent even though a minority of patients have hypogammaglobulinemia. As this population ages, this has important implications for management. [ABSTRACT FROM AUTHOR]

Abstract: Hypogammaglobulinemia has been described as a secondary consequence of many disorders. It is also the seminal finding in many primary immune deficiencies. There are few studies examining the global etiologies of hypogammaglobulinemia. This study undertook a database discovery of all cases of laboratory-defined hypogammaglobulinemia identified in a large tertiary care pediatric hospital setting between August of 1990 until June of 2006. Eight thousand three hundred and four IgG levels were sent during that time frame. One thousand two hundred and ninety-five specimens from 680 individual patients exhibited hypogammaglobulinemia and these patients represent the study population. The majority of cases in whom an identifiable cause was found had pre-existing conditions and the IgG level was sent as part of a monitoring process. Of the 366 patients who had an IgG level obtained for diagnostic purposes, nearly half were found to have an immune deficiency. One hundred and seventy-two patients with an immune deficiency were identified. Seven percent of these had severe combined immune deficiency. Seventy-four percent of the immune deficient patients identified required active intervention with IVIG, bone marrow transplantation or other management (not including prophylactic antibiotics). Evaluating all patients with IgG levels less than half of the lower limit for age revealed 122 patients of whom 33% had a primary immune deficiency. This study provides a framework for considering causes of hypogammaglobulinemia. At the study institution, hypogammaglobulinemia was found most often as a secondary immune deficiency due to chemotherapy or from complex cardiac anomalies. The magnitude of the secondary hypogammaglobulinemia in a tertiary care setting requires public health consideration as these patients have an unknown risk of infection and an unknown risk of prolonged viral shedding; issues which could be important in epidemic settings. [Copyright &y& Elsevier]

With >36 years of data collected, PIDTC prospective (6901) and retrospective (6902) natural history studies provide an unprecedented opportunity to study hematopoietic cell transplantation (HCT) outcomes for SCID over time. Patients in this 6901/6902 analysis met PIDTC diagnostic criteria for SCID and underwent HCT. Categorial variables were analyzed between decades (a) 1982-89 (b) 1990-99 (c) 2000-09 (d) 2010-18 using the chi-square test. Continuous outcomes were compared using the Kruskal-Wallis test. Kaplan-Meier method was used for estimates of overall survival (OS). 896 children with typical (n=742) and atypical (n=154) SCID requiring HCT between 1982-2018 were enrolled. Diagnosis of SCID for reasons other than family history or newborn screening was common (60%) in early cohorts (a-c) dropping to 30% in cohort (d). Distribution of SCID genotypes changed over time (Fig 1), and novel/unknown genotypes also decreased from (a) 53% to (d) 13%, p<0.001. Due to the rise of gene therapy, there were fewer patients with adenosine deaminase deficient SCID receiving HCT in cohort (d) compared to prior decades. Median age at HCT has decreased, from 193 to 112 days of life, p<0.001. While marrow was the most common stem cell source in the 1980's (95%), currently peripheral blood stem cells and cord blood are given to 46% of patients (p<0.001). The increased use of unrelated donors parallels a decrease in mismatched related donors (Fig 2a; p<0.001). In univariate analysis, use of conditioning has increased from 12% in the 1980's to 65% currently (Fig 2b, p<0.001); contributing factors that will be evaluated in upcoming multivariate analyses include genotype, typical vs atypical SCID, and donor type. Day +100 cumulative incidence of grades 3-4 acute graft-versus-host disease (GVHD) has dropped, from 9.6% to 5.9% (p=0.02). OS has markedly improved in the last decade (Fig 3a), with 1- and 5-year OS being 90 and 87%, respectively (p=0.02). In particular, gains have been made in OS when using alternative donors (p=0.02) (Fig 3c,d) while OS for matched sibling HCT remains high (Fig 3b). This longitudinal data set, spanning the implementation of NBS and advancements in diagnostics and supportive care, highlights improved OS after HCT for SCID, including alternative donors. Exploration of decreased toxicity approaches that maintain high OS and engraftment are warranted. [ABSTRACT FROM AUTHOR]

Chronic granulomatous disease is a neutrophil disorder in which phagocytic cells fail to produce a respiratory burst. Five genetic types of chronic granulomatous disease have been described and in each case the clinical manifestations relate to the inability to effectively kill catalase-positive organisms. It is classically described as a pure disorder of intracellular killing, with preservation of other aspects of phagocytic function such as migration and phagocytosis and normal function of nonmyeloid cells. This article describes a heretofore unrecognized feature of chronic granulomatous disease. Fifty-three patients with chronic granulomatous disease and 42 age-matched controls were studied by flow cytometry. Total T cell numbers and CD4 and CD8 T cell numbers were compared between patients and controls. Patients with chronic granulomatous disease had diminished T cell numbers compared to controls after 3 years of age. The difference increased with age. It is not known whether diminished T cell numbers influence the susceptibility to infections in these patients, but T cell effects could represent a significant cofactor for infection. [Copyright &y& Elsevier]

We have identified 14 patients with diverse primary immunodeficiencies who have developed progressive neurodegeneration of unknown etiology. All patients had received immunoglobulin replacement therapy for a mean duration of 6.5 years (range of 0.5–13.5 years) at the time of first neurological symptoms. Diagnostic tests of blood and cerebrospinal fluid analyses included chemistry, cultures, PCR for viral genomes, and cytology. In addition, neuroimaging and electrophysiologic studies were performed. Brain tissue histology (n = 5) revealed nonspecific encephalitis with microglial infiltration and neuronal loss. Twelve patients died 6 months to 15 years (median 4.3 years) after onset of neurologic findings. No evidence of any infectious disease that could have explained our patients'' progressive encephalopathy was found either during their lifetimes or postmortem. These patients may have had an unusual manifestation of primary immunodeficiency diseases, an autoimmune reaction against neuronal tissue, a yet undefined infectious agent, or a complication of IVIG therapy. To help determine the etiology of this rare complication, an international surveillance system for primary immunodeficiency patients who develop progressive neurodegeneration of unknown cause is recommended. [Copyright &y& Elsevier]