Germline IKAROS dimerization haploinsufficiency causes hematologic cytopenias and malignancies.

IKAROS is a transcription factor forming homo- and heterodimers and regulating lymphocyte development and function. Germline mutations affecting the IKAROS N-terminal DNA binding domain, acting in a haploinsufficient or dominant-negative manner, cause immunodeficiency. Herein, we describe 4 germline heterozygous IKAROS variants affecting its C-terminal dimerization domain, via haploinsufficiency, in 4 unrelated families. Index patients presented with hematologic disease consisting of cytopenias (thrombocytopenia, anemia, neutropenia)/Evans syndrome and malignancies (T-cell acute lymphoblastic leukemia, Burkitt lymphoma). These dimerization defective mutants disrupt homo- and heterodimerization in a complete or partial manner, but they do not affect the wild-type allele function. Moreover, they alter key mechanisms of IKAROS gene regulation, including sumoylation, protein stability, and the recruitment of the nucleosome remodeling and deacetylase complex; none affected in N-terminal DNA binding defects. These C-terminal dimerization mutations are largely associated with hematologic disorders, display dimerization haploinsufficiency and incomplete clinical penetrance, and differ from previously reported allelic variants in their mechanism of action. Dimerization mutants contribute to the growing spectrum of IKAROS-associated diseases displaying a genotype-phenotype correlation.

Rituximab and antimetabolite treatment of granulomatous and lymphocytic interstitial lung disease in common variable immunodeficiency.

BACKGROUND: Granulomatous and lymphocytic interstitial lung disease (GLILD) is a life-threatening complication in patients with common variable immunodeficiency (CVID), but the optimal treatment is unknown. OBJECTIVE: Our aim was to determine whether rituximab with azathioprine or mycophenolate mofetil improves the high-resolution computed tomography (HRCT) chest scans and/or pulmonary function test results in patients with CVID and GLILD. METHODS: A retrospective chart review of clinical and laboratory data on 39 patients with CVID and GLILD who completed immunosuppressive therapy was performed. Chest HRCT scans, performed before therapy and after the conclusion of therapy, were blinded, randomized, and scored independently by 2 radiologists. Differences between pretreatment and posttreatment HRCT scan scores, pulmonary function test results, and lymphocyte subsets were analyzed. Whole exome sequencing was performed on all patients. RESULTS: Immunosuppressive therapy improved patients' HRCT scan scores (P < .0001), forced vital capacity (P = .0017), FEV1 (P = .037), and total lung capacity (P = .013) but not their lung carbon monoxide diffusion capacity (P = .12). Nine patients relapsed and 6 completed retreatment, with 5 of 6 of these patients (83%) having improved HRCT scan scores (P = .063). Relapse was associated with an increased number of B cells (P = .016) and activated CD4 T cells (P = .016). Four patients (10%) had pneumonia while undergoing active treatment, and 2 patients (5%) died after completion of therapy. Eight patients (21%) had a damaging mutation in a gene known to predispose (TNFRSF13B [n = 3]) or cause a CVID-like primary immunodeficiency (CTLA4 [n = 2], KMT2D [n = 2], or BIRC4 [n = 1]). Immunosuppression improved the HRCT scan scores in patients with (P = .0078) and without (P < .0001) a damaging mutation. CONCLUSIONS: Immunosuppressive therapy improved the radiographic abnormalities and pulmonary function of patients with GLILD. A majority of patients had sustained remissions.

The Use of Salmonella Typhim Vaccine to Diagnose Antibody Deficiency.

PURPOSE: The specific antibody response to the unconjugated 23-valent pneumococcal polysaccharide vaccine is one of the most common tests used to assess for possible humoral immunodeficiency. The results can be difficult to interpret because most people have been immunized with one or more of the pneumococcal vaccines and there is controversy regarding what constitutes a normal response. To circumvent this problem, we developed an ELISA to measure IgG-specific antibodies to the Salmonella Vi Typhim (S. Typhim) vaccine, a pure polysaccharide vaccine, which is a neoantigen for the vast majority of people in the USA. METHODS: We compared the pre- and post-vaccination serum titers to the Vi Typhim vaccine in healthy controls (n = 22), patients previously diagnosed with a primary immunodeficiency (n = 30), and patients referred for possible humoral immune deficiency (n = 29). We also determined if the S. Typhim vaccine could be used to assess specific antibody responses in people on antibody replacement therapy. RESULTS: Following immunization with the S. Typhim vaccine, we found that a 2-fold increase in titers is 100% sensitive and specific in detecting known humoral immune deficiencies as determined by ROC curve analysis. This cut-off value was successfully applied to possible immune deficiency patients (n = 29), resulting in the diagnosis of seven subjects with humoral immunodeficiency. The use of immunoglobulin replacement therapy did not affect the median response ratios compared to subjects not receiving gammaglobulin. CONCLUSION: This study suggests that measurement of the specific antibody response to the S. Typhim vaccine may have advantages over pneumococcal vaccination in the evaluation of the humoral immune response.

X-linked Hyper IgM Syndrome Presenting as Pulmonary Alveolar Proteinosis.

PURPOSE: X-linked hyper IgM syndrome (XHIGM) is a combined immunodeficiency caused by mutations in the CD40 ligand (CD40L) gene that typically results in decreased or absent CD40L expression on activated T cells, leading to defective class switching and somatic hypermutation. We describe an infant who presented with respiratory failure due to pulmonary alveolar proteinosis (PAP) with a novel damaging missense mutation in the CD40L gene. METHODS: Whole exome sequencing (WES) was used to identify a mutation in the CD40L gene. CD40L expression and function were determined by flow cytometry. RESULTS: A 5-month-old previously-healthy male presented with respiratory failure and diffuse pulmonary ground glass opacities on CT scan of the chest. Laboratory evaluation revealed an undetectable IgG, normal IgA, and elevated IgM. A bronchoalveolar lavage demonstrated pulmonary alveolar proteinosis. WES demonstrated a c.608G > C mutation in the CD40L gene resulting in p.R203T. Flow cytometry demonstrated normal CD40L expression on activated T cells but absent binding of CD40-Ig to CD40L on activated patient T cells. CONCLUSIONS: The clinical manifestations of XHIGM in our patient had several unique features, including the presentation with PAP, normal serum IgA, and expression of non-functional CD40L on activated T cells. To our knowledge, this is the first published case of PAP in a patient with XHIGM.

Health-Related Quality of Life and Health Resource Utilization in Patients with Primary Immunodeficiency Disease Prior to and Following 12 Months of Immunoglobulin G Treatment.

PURPOSE: Health-related quality of life (HRQOL) has not been examined in patients with predominant antibody deficiency both pre- and post-immunoglobulin G (IgG) treatment initiation. HRQOL and health resource utilization (HRU) were assessed in newly diagnosed patients with primary immunodeficiency disease (PIDD) pre- and 12 months post-IgG treatment initiation. METHODS: Adults (age ≥18 years) completed the 36-item Short Form Health Survey, version 2; pediatric patients (PP)/caregivers completed the Pediatric Quality of Life Inventory (PedsQL). Scores were compared with normative data from the US general population (GP) and patients with other chronic conditions (OCC). RESULTS: Seventeen adult patients (APs), 8 PPs, and 8 caregivers completed baseline assessments. APs had significantly lower baseline mean physical component summary scores versus GP (37.4 vs 50.5, p < 0.01) adults with chronic back pain (44.1, p < 0.05) or cancer (44.4, p < 0.05) and lower mental component summary scores versus GP (41.6 vs 49.2, p < 0.05). PPs had lower PedsQL total (63.1 vs 82.7), physical summary (64.5 vs 84.5), and psychosocial summary (62.5 vs 81.7) scores versus GP. Post-IgG treatment, 14 APs, 6 PPs, and 8 caregivers completed assessments. Hospital admissions (0.2 versus 1.8, p < 0.01), serious infections (3.3 versus 10.9, p < 0.01) and antibiotic prescriptions (3.0 versus 7.1; p < 0.01) decreased significantly overall. While APs reported significant improvement in role-physical (p = 0.01), general health (p < 0.01), and social functioning (p = 0.02) and caregivers in vitality (p < 0.01), PPs did not. CONCLUSIONS: Pre-IgG treatment, patients with PIDD experienced diminished HRQOL versus GP and patients with OCC; post-treatment, HRU decreased and certain HRQOL aspects improved for APs and caregivers.

Gain of Function Mutations of PIK3CD as a Cause of Primary Sclerosing Cholangitis.

Gain of function (GOF) mutation in the p110δ catalytic subunit of the phosphatidylinositol-3-OH kinase (PIK3CD) is the cause of a primary immunodeficiency (PID) characterized by recurrent sinopulmonary infections and lymphoproliferation. We describe a family of two adults and three children with GOF mutation in PIK3CD, all with recurrent sinopulmonary infections and varied infectious and non-infectious complications. The two adults have Primary Sclerosing Cholangitis (PSC) without evidence of Cryptosporidium parvum infection and have required liver transplantation. PSC is a novel phenotype of GOF mutation in PIK3CD.

Use of combination chemotherapy for treatment of granulomatous and lymphocytic interstitial lung disease (GLILD) in patients with common variable immunodeficiency (CVID).

PURPOSE: A subset of patients with common variable immunodeficiency (CVID) develops granulomatous and lymphocytic interstitial lung disease (GLILD), a restrictive lung disease associated with early mortality. The optimal therapy for GLILD is unknown. This study was undertaken to see if rituximab and azathioprine (combination chemotherapy) would improve pulmonary function and/or radiographic abnormalities in patients with CVID and GLILD. METHODS: A retrospective chart review of patients with CVID and GLILD who were treated with combination chemotherapy was performed. Complete pulmonary function tests (PFTs) and high-resolution computed tomography (HRCT) scans of the chest were done prior to therapy and >6 months later. HRCT scans of the chest were blinded, randomized, and scored independently (in pairs) by two radiologists. The differences between pre- and post-treatment HRCT scores and PFT parameters were analyzed. RESULTS: Seven patients with CVID and GLILD met inclusion criteria. Post-treatment increases were noted in both FEV1 (p=0.034) and FVC (p=0.043). HRCT scans of the chest demonstrated improvement in total score (p=0.018), pulmonary consolidations (p=0.041), ground-glass opacities (p=0.020) nodular opacities (p=0.024), and both the presence and extent of bronchial wall thickening (p=0.014, 0.026 respectively). No significant chemotherapy-related complications occurred. CONCLUSIONS: Combination chemotherapy improved pulmonary function and decreased radiographic abnormalities in patients with CVID and GLILD.

Autoantibody stabilization of the classical pathway C3 convertase leading to C3 deficiency and Neisserial sepsis: C4 nephritic factor revisited.

C3 deficiency is a rare disorder that leads to recurrent pyogenic infections. Here we describe a previously healthy 18 y/o Caucasian male with severe meningococcal disease. Total hemolytic activity was zero secondary to an undetectable C3. The C3 gene was normal by sequencing. Mixing the patient's serum with normal human serum led to C3 consumption. An IgG autoantibody in the patient's serum was identified that stabilized the classical pathway C3 and C5 convertases, thus preventing decay of these enzyme complexes. This autoantibody is an example of a C4 nephritic factor, with an additional feature of stabilizing the C5 convertase. Previous patients with C4 nephritic factor had membranoproliferative glomerulonephritis. Two years after presentation, this patient's C3 remains undetectable with no evidence of renal disease. We revisit the role of autoantibodies to classical pathway convertases in disease, review the literature on C4-NeF and comment on its detection in the clinical laboratory.

Newborn screening for severe combined immunodeficiency; the Wisconsin experience (2008-2011).

Severe combined immunodeficiency is a life-threatening primary immune deficiency characterized by low numbers of naïve T cells. Early diagnosis and treatment of this disease decreases mortality. In 2008, Wisconsin began newborn screening of infants for severe combined immunodeficiency and other forms of T-cell lymphopenia by the T-cell receptor excision circle assay. In total, 207,696 infants were screened. Seventy-two infants had an abnormal assay. T-cell numbers were normal in 38 infants, abnormal in 33 infants, and not performed in one infant, giving a positive predictive value for T-cell lymphopenia of any cause of 45.83% and a specificity of 99.98%. Five infants with severe combined immunodeficiency/severe T-cell lymphopenia requiring hematopoietic stem cell transplantation or other therapy were detected. In summary, the T-cell receptor excision circle assay is a sensitive and specific test to identify infants with severe combined immunodeficiency and severe T-cell lymphopenia that leads to life-saving therapies such as hematopoietic stem cell transplantation prior to the acquisition of severe infections.

Allergic manifestations of inborn errors of immunity and their impact on the diagnosis: A worldwide study.

Background: Allergies have long been observed in Inborn Errors of Immunity (IEI) and might even be the first presentation resulting in delayed diagnosis or misdiagnosis in some cases. However, data on the prevalence of allergic diseases among IEI patients are limited and contradictory. Objective: To provide a worldwide view of allergic diseases, across a broad spectrum of IEI, and their impact on the timely diagnosis of IEI. Methods: This is a worldwide study, conceived by the World Allergy Organization (WAO) Inborn Errors of Immunity Committee. A questionnaire was developed and pilot-tested and was sent via email to collect data from 61 immunology centers known to treat pediatric and/or adult IEI patients in 41 countries. In addition, a query was submitted to The United States Immunodeficiency Network (USIDNET) at its website. Results: Thirty centers in 23 countries caring for a total 8450 IEI patients responded. The USIDNET dataset included 2332 patients. Data from responders showed that a median (IQR) of 16.3% (10-28.8%) of patients experienced allergic diseases during the course of their IEI as follows: 3.6% (1.3-11.3%) had bronchial asthma, 3.6% (1.9-9.1%) atopic dermatitis, 3.0% (1.0-7.8%) allergic rhinitis, and 1.3% (0.5-3.3%) food allergy. As per the USIDNET data, the frequency of allergy among IEI patients was 68.8% (bronchial asthma in 46.9%). The percentage of IEI patients who presented initially with allergic disorders was 8% (5-25%) and diagnosis delay was reported in 7.5% (0.9-20.6%). Predominantly antibody deficiencies had the highest frequency of allergic disease followed by combined immunodeficiency with a frequency of 40.3% (19.2-62.5%) and 20.0% (10-32%) respectively. As per the data of centers, anaphylaxis occurred in 25/8450 patients (0.3%) whereas per USIDNET dataset, it occurred in 249/2332 (10.6%); drugs and food allergy were the main causes in both datasets. Conclusions: This multinational study brings to focus the relation between allergic diseases and IEI. Major allergies do occur in IEI patients but were less frequent than the general population. Initial presentation with allergy could adversely affect the timely diagnosis of IEI. There is a need for policies to raise awareness and educate primary care and other referring specialties on the association of allergic diseases with IEI. This study provides a network among centers for future prospective studies in the field.

Corrigendum: IRAK4 Deficiency in a Patient with Recurrent Pneumococcal Infections: Case Report and Review of the Literature.

[This corrects the article on p. 83 in vol. 5, PMID: 28503543.].

A Practical Approach to Newborn Screening for Severe Combined Immunodeficiency Using the T Cell Receptor Excision Circle Assay.

Severe combined immunodeficiency (SCID) is a life-threatening condition of newborns and infants caused by defects in genes involved in T cell development. Newborn screening (NBS) for SCID using the T cell receptor excision circle (TREC) assay began in Wisconsin in 2008 and has been adopted or is being implemented by all states in 2017. It has been established that NBS using the TREC assay is extremely sensitive to detect SCID in the newborn period. Some controversies remain regarding how screening positives are handled by individual states, including when to perform confirmatory flow cytometry, what is the necessary diagnostic workup of patients, what infection prophylaxis measures should be taken, and when hematopoietic stem cell transplantation should occur. In addition, the TREC can also assay detect infants with T cell lymphopenia who are not severe enough to be considered SCID; management of these infants is also evolving.

IRAK4 Deficiency in a Patient with Recurrent Pneumococcal Infections: Case Report and Review of the Literature.

Primary immunodeficiencies are genetic defects of the innate or adaptive immune system, resulting in a propensity to infections. The innate immune system is the first line of defense against pathogens and is critical to recognize microbes and start the inflammatory cascade. Sensing of microbes occurs by a number of pathogen-recognition receptors, resulting in the activation of inflammatory signal transduction pathways, such as the activation of NF-κB. Herein, we describe a case of IRAK4 deficiency, a key signal transduction molecule of toll-like and IL-1 receptors. We highlight the complexities in diagnosis of these disorders and review genetic defects of the NF-κB pathway.

An exploratory study of the cognitive, academic, and behavioral functioning of pediatric cardiothoracic transplant recipients.

CONTEXT: Limited information is available regarding the cognitive, academic, and behavioral outcomes of pediatric cardiothoracic transplant recipients. OBJECTIVE: To examine the cognitive, behavioral, and academic functioning of a group of children who have received heart, heart/lung, or lung transplants. DESIGN, PARTICIPANTS, AND SETTING: An exploratory cross-sectional outcomes study of surviving pediatric cardiothoracic transplant recipients at a Midwestern pediatric hospital. MAIN OUTCOME MEASURES: Transplant recipients completed measures of cognitive and academic functioning. Parents and teachers completed measures of behavioral functioning. Parents and transplant recipients also provided qualitative data regarding their main concerns after transplantation. RESULTS: On measures of cognitive functioning, 46% showed significant delays (> 2 SD below the normative population). Of those eligible for academic testing, 78% fell within the average range (within 1 SD of the normative population) for reading and spelling, and 57% fell within the average range for math. Twenty-seven percent of mothers, 11% of fathers, and 17% of teachers rated subjects as having significant behavioral concerns. Results highlight the need for close contact between transplant teams and school personnel to optimize outcomes. In addition, patients and families may benefit from psychological intervention after transplantation as there are ongoing concerns regarding life expectancy and quality of life.

Primary immunodeficiency diseases: a primer for PCPs.

Primary care providers (PCPs) play a key role in identifying patients with primary immunodeficiency diseases (PIDDs). This diagnosis has implications for PCPs, as patients continue to require primary care and management after a PIDD diagnosis has been made. This review presents essential information for PCPs regarding PIDDs.

Bilateral lung transplant in Gauchers type-1 disease.

We report a case of a patient who received a bilateral lung transplant for end-stage lung disease secondary to Gauchers type-1 disease with no evidence of recurrence of the disease in the transplanted lung.