Individuals with JAK1 variants are affected by syndromic features encompassing autoimmunity, atopy, colitis, and dermatitis.

Inborn errors of immunity lead to autoimmunity, inflammation, allergy, infection, and/or malignancy. Disease-causing JAK1 gain-of-function (GoF) mutations are considered exceedingly rare and have been identified in only four families. Here, we use forward and reverse genetics to identify 59 individuals harboring one of four heterozygous JAK1 variants. In vitro and ex vivo analysis of these variants revealed hyperactive baseline and cytokine-induced STAT phosphorylation and interferon-stimulated gene (ISG) levels compared with wild-type JAK1. A systematic review of electronic health records from the BioME Biobank revealed increased likelihood of clinical presentation with autoimmunity, atopy, colitis, and/or dermatitis in JAK1 variant-positive individuals. Finally, treatment of one affected patient with severe atopic dermatitis using the JAK1/JAK2-selective inhibitor, baricitinib, resulted in clinically significant improvement. These findings suggest that individually rare JAK1 GoF variants may underlie an emerging syndrome with more common presentations of autoimmune and inflammatory disease (JAACD syndrome). More broadly, individuals who present with such conditions may benefit from genetic testing for the presence of JAK1 GoF variants.

CVID-Associated Intestinal Disorders in the USIDNET Registry: An Analysis of Disease Manifestations, Functional Status, Comorbidities, and Treatment.

Common variable immunodeficiency (CVID) has been subdivided into five phenotypes, including one marked by non-infectious enteropathies that lead to significant morbidity and mortality. We examined a large national registry of patients with CVID to better characterize this population and understand how the presence of enteropathy influences nutritional status, patient function, and the risk of additional non-infectious disorders in CVID patients. We also sought to illustrate the range of treatment strategies for CVID-associated enteropathies. We extracted patient data from the United States Immunodeficiency Network (USIDNET) database, which included 1415 patients with CVID, and compared those with and without intestinal disorders. Demographic and genetic profiles, functional status, and treatments targeting intestinal disorders are reported. Intestinal disorders were present in 20% of patients with CVID, including chronic diarrhea, inflammatory bowel disease, malabsorption, and others. Compared to those without enteropathies, this patient subset exhibited significantly lower Karnofsky-Lansky functional scores, greater reliance on nutritional support, higher rates of vitamin deficiencies, and increased prevalence of hematologic disorders, liver disease, pulmonary disease, granulomatous disease, and lymphoma. Genetic data were reported for only 5% of the cohort. No mutations segregated significantly to patients with or without intestinal disease. Corticosteroids were most frequently used for treatment. Patients with CVID-associated intestinal disorders exhibit higher rates of autoimmune and inflammatory comorbidities, lymphoma, malnutrition, and debility. We review recent studies implicating specific pathways underlying this immune dysregulation. Further studies are needed to evaluate the role of targeted immunomodulatory therapies for CVID-associated intestinal disorders.

Respiratory Comorbidities Associated with Bronchiectasis in Patients with Common Variable Immunodeficiency in the USIDNET Registry.

BACKGROUND: Bronchiectasis is a major respiratory complication in patients with common variable immunodeficiency (CVID) and is associated with recurrent pulmonary infections. However, it is unclear whether other infections or non-infectious respiratory conditions are related to its development. OBJECTIVE: To identify respiratory comorbidities associated with bronchiectasis in patients with CVID. METHODS: A total of 1470 CVID patients enrolled in the USIDNET registry were included in a cross-sectional analysis. The primary outcome of our study was to determine the clinical characteristics and other respiratory conditions associated with respiratory comorbidities and physician-reported bronchiectasis. RESULTS: One hundred ninety-seven CVID patients were noted to have bronchiectasis (13.4%). Affected patients were significantly older than patients without bronchiectasis (median age 54 years vs. 49 years, p = 0.0004). These patients also had lower serum IgA (13 mg/dL IQR 60 mg/dL vs. 28.4 mg/dL IQR 66 mg/dL, p = 0.000). Notably, chronic rhinosinusitis (OR = 1.69 95%CI 1.05-2.75), sinusitis (OR = 2.06 95%CI 1.38-3.09), pneumonia (OR = 2.70 95%CI 1.88-3.88), COPD (OR = 2.66 95%CI 1.51-4.67), and interstitial lung disease (OR = 2.34 95%CI 1.41-3.91) were independently associated with the development of bronchiectasis in this population. CONCLUSION: These data suggest that lower and upper respiratory infections, chronic lower airway disease, and interstitial lung diseases are independently associated with bronchiectasis in CVID patients. Further study into predisposing conditions related to the development of bronchiectasis in CVID patients may allow prediction and early intervention strategies to prevent the development of this complication.

Who's your data? Primary immune deficiency differential diagnosis prediction via machine learning and data mining of the USIDNET registry.

PURPOSE: There are currently more than 480 primary immune deficiency (PID) diseases and about 7000 rare diseases that together afflict around 1 in every 17 humans. Computational aids based on data mining and machine learning might facilitate the diagnostic task by extracting rules from large datasets and making predictions when faced with new problem cases. In a proof-of-concept data mining study, we aimed to predict PID diagnoses using a supervised machine learning algorithm based on classification tree boosting. METHODS: Through a data query at the USIDNET registry we obtained a database of 2396 patients with common diagnoses of PID, including their clinical and laboratory features. We kept 286 features and all 12 diagnoses to include in the model. We used the XGBoost package with parallel tree boosting for the supervised classification model, and SHAP for variable importance interpretation, on Python v3.7. The patient database was split into training and testing subsets, and after boosting through gradient descent, the predictive model provides measures of diagnostic prediction accuracy and individual feature importance. After a baseline performance test, we used the Class Weighting Hyperparameter, or scale_pos_weight to correct for imbalanced classification. RESULTS: The twelve PID diagnoses were CVID (1098 patients), DiGeorge syndrome, Chronic granulomatous disease, Congenital agammaglobulinemia, PID not otherwise classified, Specific antibody deficiency, Complement deficiency, Hyper-IgM, Leukocyte adhesion deficiency, ectodermal dysplasia with immune deficiency, Severe combined immune deficiency, and Wiskott-Aldrich syndrome. For CVID, the model found an accuracy on the train sample of 0.80, with an area under the ROC curve (AUC) of 0.80, and a Gini coefficient of 0.60. In the test subset, accuracy was 0.76, AUC 0.75, and Gini 0.51. The positive feature value to predict CVID was highest for upper respiratory infections, asthma, autoimmunity and hypogammaglobulinemia. Features with the highest negative predictive value were high IgE, growth delay, abscess, lymphopenia, and congenital heart disease. For the rest of the diagnoses, accuracy stayed between 0.75 and 0.99, AUC 0.46-0.87, Gini 0.07-0.75, and LogLoss 0.09-8.55. DISCUSSION: Clinicians should remember to consider the negative predictive features together with the positives. We are calling this a proof-of-concept study to continue with our explorations. A good performance is encouraging, and feature importance might aid feature selection for future endeavors. In the meantime, we can learn from the rules derived by the model and build a user-friendly decision tree to generate differential diagnoses.

CVID-associated intestinal disorders in the USIDNET registry: An analysis of disease manifestations, functional status, comorbidities, and treatment.

Common variable immunodeficiency (CVID) has been subdivided into five phenotypes, including one marked by non-infectious enteropathies that lead to significant morbidity and mortality. We examined a large national registry of patients with CVID to better characterize this population and understand how the presence of enteropathy influences nutritional status, patient function, and the risk of additional non-infectious disorders in CVID patients. We also sought to illustrate the range of treatment strategies for CVID-associated enteropathies. We extracted patient data from the United States Immunodeficiency Network (USIDNET) database, which included 1415 patients with CVID, and compared those with and without intestinal disorders. Demographic and genetic profiles, functional status, and treatments targeting intestinal disorders are reported. Intestinal disorders were present in 20% of patients with CVID, including chronic diarrhea, inflammatory bowel disease, malabsorption, and others. Compared to those without enteropathies, this patient subset exhibited significantly lower Karnofsky-Lansky functional scores, greater reliance on nutritional support, higher rates of vitamin deficiencies, and increased prevalence of hematologic disorders, liver disease, pulmonary disease, granulomatous disease, and lymphoma. Genetic data were reported for only 5% of the cohort. No mutations segregated significantly to patients with or without intestinal disease. Corticosteroids were most frequently used for treatment. Patients with CVID-associated intestinal disorders exhibit higher rates of autoimmune and inflammatory comorbidities, lymphoma, malnutrition, and debility. We review recent studies implicating specific pathways underlying this immune dysregulation. Further studies are needed to evaluate the role of targeted immunomodulatory therapies for CVID-associated intestinal disorders.

A Registry Study of 240 Patients with X-Linked Agammaglobulinemia Living in the USA.

PURPOSE: To understand the natural history and clinical outcomes for patients with X-linked agammaglobulinemia (XLA) in the United States utilizing the United States Immunodeficiency Network (USIDNET) patient registry. METHODS: The USIDNET registry was queried for data from XLA patients collected from 1981 to 2019. Data fields included demographics, clinical features before and after diagnosis of XLA, family history, genetic mutation in Bruton's tyrosine kinase (BTK), laboratory findings, treatment modalities, and mortality. RESULTS: Data compiled through the USIDNET registry on 240 patients were analyzed. Patient year of birth ranged from 1945 to 2017. Living status was available for 178 patients; 158/178 (88.8%) were alive. Race was reported for 204 patients as follows: White, 148 (72.5%); Black/African American, 23 (11.2%); Hispanic, 20 (9.8%); Asian or Pacific Islander, 6 (2.9%), and other or more than one race, 7 (3.4%). The median age at last entry, age at disease onset, age at diagnosis, and length of time with XLA diagnosis was 15 [range (r) = 1-52 years], 0.8 [r = birth-22.3 years], 2 [r = birth-29 years], and 10 [r = 1-56 years] years respectively. One hundred and forty-one patients (58.7%) were < 18 years of age. Two hundred and twenty-one (92%) patients were receiving IgG replacement (IgGR), 58 (24%) were on prophylactic antibiotics, and 19 (7.9%) were on immunomodulatory drugs. Eighty-six (35.9%) patients had undergone surgical procedures, two had undergone hematopoietic cell transplantation, and two required liver transplantation. The respiratory tract was the most affected organ system (51.2% of patients) followed by gastrointestinal (40%), neurological (35.4%), and musculoskeletal (28.3%). Infections were common both before and after diagnosis, despite IgGR therapy. Bacteremia/sepsis and meningitis were reported more frequently before XLA diagnosis while encephalitis was more commonly reported after diagnosis. Twenty patients had died (11.2%). The median age of death was 21 years (range = 3-56.7 years). Neurologic condition was the most common underlying co-morbidity for those XLA patients who died. CONCLUSIONS: Current therapies for XLA patients reduce early mortality, but patients continue to experience complications that impact organ function. With improved life expectancy, more efforts will be required to improve post-diagnosis organ dysfunction and quality of life. Neurologic manifestations are an important co-morbidity associated with mortality and not yet clearly fully understood.

Eosinophilic gastrointestinal disorders in patients with inborn errors of immunity: Data from the USIDNET registry.

Rationale: Eosinophilic gastrointestinal disorders (EGID), including eosinophilic esophagitis (EoE), are inflammatory disorders of the gastrointestinal mucosa mediated by complex immune mechanisms. Although there have been initial reports of EGID in patients with inborn errors of immunity (IEI), little is known about the presentation of EGID in immunodeficient individuals. Methods: We queried the U.S. Immunodeficiency Network (USIDNET) for patient records including the terms eosinophilic esophagitis, gastritis, enteritis, or colitis. We analyzed 74 patient records from the database, including diagnoses, demographics, infectious history, laboratory findings, genetic studies, therapeutic interventions, and clinical outcomes. Results: We examined 74 patient records. A total of 61 patients had isolated EoE, and 13 had distal gastrointestinal involvement consistent with EGID. The most common IEI were common variable immunodeficiency (43.2%), some form of combined immunodeficiency (21.6%), chronic granulomatous disease (8.1%), hyper-IgE syndrome (6.8%), and autoimmune lymphoproliferative syndrome (6.8%). The median age at presentation with IEI was 0.5 years (IQR 1.725, max 39 years) and 56.76% were male. Approximately 20% of the patients in the cohort received a hematopoietic stem cell transplantation for treatment of IEI, but the timing of the HSCT in relationship to the EGID diagnosis was unknown. Conclusions: Here, we report EGID in a diverse cohort of IEI patients, suggesting that both non-EoE EGID and EoE can be seen as comorbid conditions with a variety of IEI. Our data suggests that EGID may be more common in patients with IEI than would be expected based on estimates of EGID in the general population.

Ocular Manifestations in Primary Immunodeficiency Disorders: A Report From the United States Immunodeficiency Network (USIDNET) Registry.

BACKGROUND: Few published studies address eye disease in primary immunodeficiency (PID) despite ocular infections and autoimmune disease being known manifestations of immunodeficient states. OBJECTIVE: Data from the USIDNET Registry provide a resource to study ocular ailments in subjects with PID. METHODS: Ocular manifestations and patient characteristics were determined using data from 4624 patients with PID enrolled in the US Immunodeficiency Network (USIDNET) Registry. RESULTS: A total of 519 (11.2%) patients had recorded ocular diseases. Those with autoinflammatory disorders (n = 4 of 7 [57.1%]), intrinsic and innate immunity defects (n = 9 of 44 [20.5%]), and immune dysregulation (n = 27 of 142 [19.0%]) had the highest percentage of ocular diseases for the PID diagnosis category. Of the 67.6% with infections, 85.5% had conjunctivitis. Bacteria (56.2%) and viruses (27.4%) were the most common microorganisms reported, with Staphylococcus (31.7%), Haemophilus (26.8%), and Streptococcus (22.0%) being the most common bacteria isolated. Those with a history of eye infections had lower immunoglobulin levels, lower CD19 B-cell percentages, and a lower number of protective pneumococcal titers. In patients with noninfectious ocular complications, 30.8% had vision changes, with retina (n = 20 [8.0%]), cataract (n = 16 [6.4%]), and nerve diseases (n = 16 [6.4%]) also being common. Many patients with ocular disease had serious sequelae, with 12.7% undergoing eye surgery and 10.6% having a vision-based disability. CONCLUSIONS: Vision loss and conjunctivitis were the most commonly reported ocular complications and pose large quality-of-life issues. Learning more about ocular disease in PID will increase awareness about the importance of addressing and evaluating for these ailments.

Chronic Granulomatous Disease With Inflammatory Bowel Disease: Clinical Presentation, Treatment, and Outcomes From the USIDNET Registry.

BACKGROUND: Chronic granulomatous disease (CGD) is an inborn error of immunity caused by defects in the phagocytic nicotinamide adenine dinucleotide phosphate oxidase complex, leading to increased susceptibility to infection and inflammatory autoimmune diseases. Up to 50% of patients have gastrointestinal (GI) involvement and meet diagnostic criteria for inflammatory bowel disease (CGD-IBD). OBJECTIVE: We analyzed patients with CGD from the US Immunodeficiency Network (USIDNET) registry to determine whether IBD changes the presentation, treatment, and outcomes of patients with CGD. METHODS: A retrospective evaluation of CGD cases from the USIDNET registry was completed. CGD-IBD was defined as the presence of any major physician-reported inflammatory, noninfectious GI disease manifestation. Demographic information, conditions, infections, antimicrobial therapies, immunomodulator use, and hematopoietic stem cell transplantation data were analyzed. RESULTS: Of 194 patients with a diagnosis of CGD, 96 met criteria for IBD and 98 were categorized in the non-IBD group. Patients with CGD-IBD had an increased rate of infection compared with the non-IBD group (0.66 vs 0.36 infections/patient/year). Enteric organism infections were more common in patients with IBD. Immunomodulators were used at a significantly higher percentage in patients with IBD compared with patients without IBD (80% vs 56%, P < .001). Of the entire CGD cohort, 17 patients died (8.8%), with no significant difference between patients with IBD and patients without IBD (P = 1.00). CONCLUSION: Infectious events, enteric organism infections, and use of immunomodulatory drugs were higher in patients with IBD than patients without IBD; however, mortality was not increased. Patients with CGD and concurrent IBD are at increased risk for disease complications, supporting the importance of early recognition, diagnosis, and treatment.

Lymphoproliferative Disease in CVID: a Report of Types and Frequencies from a US Patient Registry.

PURPOSE: Lymphoproliferative disease in common variable immunodeficiency disease (CVID) is heterogeneous in pathogenesis and ranges from non-malignant lymphoid hyperplasia to lymphoma. METHODS: The United States Immunodeficiency Network (USIDNET) patient registry was queried for lymphoproliferative diseases reported in CVID patients. Diagnoses included as possible manifestations of lymphoproliferation included lymphadenopathy, lymphoid hyperplasia, lymphocytic inflammation, lymphocytosis, and gammopathy. RESULTS: Among 1091 CVID patients, lymphoproliferative conditions were reported in 17.2% (N = 188). These conditions included lymphadenopathy (N = 192, 12.3%), lymphoid hyperplasia or lymphocytic inflammation (N = 50, 4.6%), lymphocytosis (N = 3, 0.3%), and gammopathies (N = 3, 0.3%). Of the 188 patients with lymphoproliferative conditions, 15 (8%) also had a diagnosis of lymphoma, while the remaining 173 (92%) did not. Nine (4.8%) had a diagnosis of non-lymphomatous malignancy including basal cell carcinoma (N = 3, 1.6%), thyroid carcinoma (N = 2, 1.1%), gynecologic cancer (N = 2, 1.1%), testicular cancer (N = 1), and vocal cord carcinoma (N = 1). CVID patients with lymphoma were older than patients with lymphoproliferative disease who did not have a diagnosis of lymphoma at the time of analysis (median age 49 vs. 35 years, p = 0.005). CVID patients with lymphoproliferative disease had 2.5 times higher odds of having chronic lung disease compared with those with lymphoma (OR = 0.4, p = 0.049). There were no significant differences in the frequency of autoimmune, gastrointestinal, hepatic, or granulomatous disease between these populations. CONCLUSIONS: While CVID patients are at increased risk for lymphoma, lymphoproliferation may be observed in the absence of a concurrent hematologic or solid tumor malignancy.

A case of aberrant CD8 T cell-restricted IL-7 signaling with a Janus kinase 3 defect-associated atypical severe combined immunodeficiency.

Severe combined immunodeficiency (SCID) disorders compromise lymphocyte numbers and/or function. One subset of SCID typically affects T cell and Natural Killer (NK) cell development in tandem (T-B+NK-) due to mutations arising in the genes encoding the common γ chain or Janus Kinase 3 (JAK3). In rare circumstances, mutations in the JAK3 gene have been reported to cause atypical SCID that selectively affects T cells (T-B+NK+). Here we describe a case involving a female infant who was referred to our institution on day nine of life following an abnormal newborn screen result for T-SCID. Immunological assessments revealed a T-B+NK+ phenotype and molecular analyses, including whole exome sequencing, identified compound heterozygous JAK3 variants (R117C and E658K). Pre-transplant phosflow analyses revealed a persistent IL-7 signaling defect, based on phospho-STAT5 measurements, only in CD8 but not CD4 T cells. Intriguingly, phospho-STAT5 signals in response to IL-2 stimulation were not affected in either CD4 or CD8 T cells. The pre-transplant clinical course was unremarkable, and the patient received a cord-blood stem cell transplant on day 716 of life. Post-transplant monitoring revealed that despite normalization of lymphocyte counts, the CD8 T cell-restricted IL-7 signaling defect was still evident at day 627 post-transplant (phospho-STAT5 signal in CD8 T cells was > 60% reduced compared with CD4 T cells). The post-transplant clinical course has also been complicated by identification of autoimmune responses and likely GVHD-induced ichthyosis. To the best of our knowledge, this report represents the third case of JAK3-associated atypical SCID reported in the literature.

Dominant activating RAC2 mutation with lymphopenia, immunodeficiency, and cytoskeletal defects.

Ras-related C3 botulinum toxin substrate 2 (RAC2), through interactions with reduced NAD phosphate oxidase component p67 phox , activates neutrophil superoxide production, whereas interactions with p21-activated kinase are necessary for fMLF-induced actin remodeling. We identified 3 patients with de novo RAC2[E62K] mutations resulting in severe T- and B-cell lymphopenia, myeloid dysfunction, and recurrent respiratory infections. Neutrophils from RAC2[E62K] patients exhibited excessive superoxide production, impaired fMLF-directed chemotaxis, and abnormal macropinocytosis. Cell lines transfected with RAC2[E62K] displayed characteristics of active guanosine triphosphate (GTP)-bound RAC2 including enhanced superoxide production and increased membrane ruffling. Biochemical studies demonstrated that RAC2[E62K] retains intrinsic GTP hydrolysis; however, GTPase-activating protein failed to accelerate hydrolysis resulting in prolonged active GTP-bound RAC2. Rac2+/E62K mice phenocopy the T- and B-cell lymphopenia, increased neutrophil F-actin, and excessive superoxide production seen in patients. This gain-of-function mutation highlights a specific, nonredundant role for RAC2 in hematopoietic cells that discriminates RAC2 from the related, ubiquitous RAC1.

Prevalence of Granulomas in Patients With Primary Immunodeficiency Disorders, United States: Data From National Health Care Claims and the US Immunodeficiency Network Registry.

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.

Autoimmune Cytopenias and Associated Conditions in CVID: a Report From the USIDNET Registry.

PURPOSE: Autoimmune cytopenia is frequently a presenting manifestation of common variable immune deficiency (CVID). Studies characterizing the CVID phenotype associated with autoimmune cytopenias have mostly been limited to large referral centers. Here, we report prevalence of autoimmune cytopenias in CVID from the USIDNET Registry and compare the demographics and clinical features of patients with and without this complication. METHODS: Investigators obtained demographic, laboratory, and clinical data on CVID patients within the USIDNET Registry. Patients were considered to have autoimmune cytopenia if they had a diagnosis of hemolytic anemia, immune thrombocytopenia (ITP), or autoimmune neutropenia. Baseline characteristics and associated complications of those with autoimmune cytopenia (+AC) and those without (-AC) were compared. RESULTS: Of 990 CVID patients included in the analysis, 10.2% (N = 101) had a diagnosis consistent with autoimmune cytopenia: ITP was diagnosed in 7.4% (N = 73), hemolytic anemia in 4.5% (N = 45), and autoimmune neutropenia in 1% (N = 10). Age at diagnosis, gender, and baseline Ig values did not differ between the +AC and -AC groups. The +AC group was significantly more likely to have one or more other CVID-associated non-infectious complications (OR = 2.9; 95%-CI: 1.9-4.6, P < 0.001), including lymphoproliferation, granulomatous disease, lymphomas, hepatic disease, interstitial lung diseases, enteropathy, and organ-specific autoimmunity. CONCLUSIONS: Autoimmune cytopenias are a common manifestation in CVID and are likely to be associated with other non-infectious CVID-related conditions. In light of prior studies showing increased morbidity and mortality in CVID patients with such complications, a diagnosis of autoimmune cytopenia may have prognostic significance in CVID.

Serologic response and clinical efficacy of influenza vaccination in children and young adults on chemotherapy for cancer.

BACKGROUND: Influenza is a health risk to children receiving chemotherapy for cancer. An absolute lymphocyte count (ALC) >1,000 cells/mm(3) has been associated with the ability to produce an immune response to influenza vaccine during chemotherapy. However, clinical efficacy of influenza vaccination during chemotherapy remains unclear. PROCEDURE: We conducted a prospective cohort study in children receiving chemotherapy for cancer during two consecutive influenza seasons. Assessments of immune cells and serologic response were measured immediately before and after receiving influenza vaccine. Patients were monitored for influenza or influenza-like illness (ILI). RESULTS: Two hundred fifty-nine patients were studied over 2 years. The seroresponse rate was 62% (98/157). The median ALC at vaccination was higher in seroresponders than nonresponders, 854 cells/mm(3) versus 602 cells/mm(3) , respectively (P < 0.036). Univariate analysis showed that patients with an ALC <1,000 cells/mm(3) at the time of vaccination were twice as likely to be sero-nonresponders (P < 0.02, OR = 2.4, 95% CI: 1.1-5.0). Twelve percent (31/259) of patients developed influenza, of whom all had fever at presentation, 26% (8/31) required hospitalization, and 81% (25/31) had chemotherapy delays. No deaths were associated with influenza infection. The proportion of patients with influenza was not different between seroresponders and nonresponders. CONCLUSIONS: Influenza infection following immunization remains a source of morbidity in children undergoing chemotherapy. Lymphopenia at vaccination predicted sero-nonresponse. Seroresponse was not associated with a decreased frequency of influenza infection or ILI when compared to sero-nonresponders, suggesting clinical effectiveness of vaccination is likely multifactorial. Further investigation into the efficacy of the influenza vaccine is needed to refine immunization recommendations.

Hyper IgM Syndrome: a Report from the USIDNET Registry.

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.

Characterization of T and B cell repertoire diversity in patients with RAG deficiency.

Recombination-activating genes 1 and 2 (RAG1 and RAG2) play a critical role in T and B cell development by initiating the recombination process that controls the expression of T cell receptor (TCR) and immunoglobulin genes. Mutations in the RAG1 and RAG2 genes in humans cause a broad spectrum of phenotypes, including severe combined immunodeficiency (SCID) with lack of T and B cells, Omenn syndrome, leaky SCID, and combined immunodeficiency with granulomas or autoimmunity (CID-G/AI). Using next-generation sequencing, we analyzed the TCR and B cell receptor (BCR) repertoire in 12 patients with RAG mutations presenting with Omenn syndrome (n = 5), leaky SCID (n = 3), or CID-G/AI (n = 4). Restriction of repertoire diversity skewed usage of variable (V), diversity (D), and joining (J) segment genes, and abnormalities of CDR3 length distribution were progressively more prominent in patients with a more severe phenotype. Skewed usage of V, D, and J segment genes was present also within unique sequences, indicating a primary restriction of repertoire. Patients with Omenn syndrome had a high proportion of class-switched immunoglobulin heavy chain transcripts and increased somatic hypermutation rate, suggesting in vivo activation of these B cells. These data provide a framework to better understand the phenotypic heterogeneity of RAG deficiency.

Transplantation outcomes for severe combined immunodeficiency, 2000-2009.

BACKGROUND: The Primary Immune Deficiency Treatment Consortium was formed to analyze the results of hematopoietic-cell transplantation in children with severe combined immunodeficiency (SCID) and other primary immunodeficiencies. Factors associated with a good transplantation outcome need to be identified in order to design safer and more effective curative therapy, particularly for children with SCID diagnosed at birth. METHODS: We collected data retrospectively from 240 infants with SCID who had received transplants at 25 centers during a 10-year period (2000 through 2009). RESULTS: Survival at 5 years, freedom from immunoglobulin substitution, and CD3+ T-cell and IgA recovery were more likely among recipients of grafts from matched sibling donors than among recipients of grafts from alternative donors. However, the survival rate was high regardless of donor type among infants who received transplants at 3.5 months of age or younger (94%) and among older infants without prior infection (90%) or with infection that had resolved (82%). Among actively infected infants without a matched sibling donor, survival was best among recipients of haploidentical T-cell-depleted transplants in the absence of any pretransplantation conditioning. Among survivors, reduced-intensity or myeloablative pretransplantation conditioning was associated with an increased likelihood of a CD3+ T-cell count of more than 1000 per cubic millimeter, freedom from immunoglobulin substitution, and IgA recovery but did not significantly affect CD4+ T-cell recovery or recovery of phytohemagglutinin-induced T-cell proliferation. The genetic subtype of SCID affected the quality of CD3+ T-cell recovery but not survival. CONCLUSIONS: Transplants from donors other than matched siblings were associated with excellent survival among infants with SCID identified before the onset of infection. All available graft sources are expected to lead to excellent survival among asymptomatic infants. (Funded by the National Institute of Allergy and Infectious Diseases and others.).

A systematic analysis of recombination activity and genotype-phenotype correlation in human recombination-activating gene 1 deficiency.

BACKGROUND: The recombination-activating gene (RAG) 1/2 proteins play a critical role in the development of T and B cells by initiating the VDJ recombination process that leads to generation of a broad T-cell receptor (TCR) and B-cell receptor repertoire. Pathogenic mutations in the RAG1/2 genes result in various forms of primary immunodeficiency, ranging from T(-)B(-) severe combined immune deficiency to delayed-onset disease with granuloma formation, autoimmunity, or both. It is not clear what contributes to such heterogeneity of phenotypes. OBJECTIVE: We sought to investigate the molecular basis for phenotypic diversity presented in patients with various RAG1 mutations. METHODS: We have developed a flow cytometry-based assay that allows analysis of RAG recombination activity based on green fluorescent protein expression and have assessed the induction of the Ighc locus rearrangements in mouse Rag1(-/-) pro-B cells reconstituted with wild-type or mutant human RAG1 (hRAG1) using deep sequencing technology. RESULTS: Here we demonstrate correlation between defective recombination activity of hRAG1 mutant proteins and severity of the clinical and immunologic phenotype and provide insights on the molecular mechanisms accounting for such phenotypic diversity. CONCLUSIONS: Using a sensitive assay to measure the RAG1 activity level of 79 mutations in a physiologic setting, we demonstrate correlation between recombination activity of RAG1 mutants and the severity of clinical presentation and show that RAG1 mutants can induce specific abnormalities of the VDJ recombination process.

The hyper IgM syndromes.

The hyper IgM syndromes are a group of rare inherited immune deficiency disorders characterized by impairment of immunoglobulin isotype switching resulting from defects in the CD40 ligand/CD40 signaling pathway. X-linked forms of hyper IgM are caused by defects in the CD40 ligand gene or NF-κB essential modulator, while autosomal recessive forms of hyper IgM are caused by defects in CD40 or downstream signaling molecules including activation-induced cytidine deaminase, uracil N glycosylase or postmeiotic segregation increased 2. The loss of interaction between CD40 and its ligand results in an impairment of T cell function, of B cell differentiation and of monocyte function while only B cell differentiation appears to be affected in defects of sinaling molecules downstream of CD40 with the exception of defects of the NF-κB complex, which mediates signaling via multiple receptor pathways. With many genetic defects in the hyper IgM syndrome identified, it is possible to diagnose patients definitively, to perform genetic screening, and to delineate the clinical manifestations of the different diseases in this syndrome. Stem cell transplantation is an available therapeutic option for defects that result in a combined immunodeficiency while antibody replacement appears sufficient for the strictly humoral immunodeficiencies.