MHC class II deficiency: Clinical, immunological, and genetic insights in a large multicenter cohort.

BACKGROUND: Major Histocompatibility Complex Class II (MHC-II) deficiency, a combined immunodeficiency, results from loss of Human Leukocyte Antigen class II expression on antigen-presenting cells. Currently, hematopoietic stem cell transplantation (HSCT) stands as the sole curative approach, though factors influencing patient outcomes remain insufficiently explored. OBJECTIVE: Our aim was to elucidate the clinical, immunological, and genetic profiles associated with MHC-II deficiency and identify prognostic indicators that affect survival rates. METHODS: In this multicenter retrospective analysis, we gathered data from 35 patients diagnosed with MHC-II deficiency across 12 centers in Turkey. We recorded infection histories, gene mutations, immune cell subsets, and surface MHC-II expression on blood cells. We conducted survival analyses to evaluate the impact of various factors on patient outcomes. RESULTS: Predominant symptoms observed were pneumonia (n=29, 82.9%), persistent diarrhea (n=26, 74.3%), and severe infections (n=26, 74.3%). The RFXANK gene mutation (n=9) was the most frequent, followed by mutations in RFX5 (n=8), CIITA (n=4), and RFXAP (n=2) genes. Patients with RFXANK mutations presented with later onset and diagnosis compared to those with RFX5 mutations (p=0.0008 and p=0.0006, respectively), alongside a more significant diagnostic delay (p=0.020). A notable founder effect was observed in 5 patients with a specific RFX5 mutation (c.616G>C). The overall survival rate for patients was 28.6% (n=10), showing a significantly higher proportion in individuals with HSCT (n=8, 80%). Early demise (p=0.006) and higher CD8+ T-cell counts were observed in patients with the RFX5 mutations compared to RFXANK-mutant patients (p=0.006 and p=0.009, respectively). CONCLUSION: The study delineates the genetic and clinical panorama of MHC-II deficiency, emphasizing the prevalence of specific gene mutations such as RFXANK and RFX5. These insights facilitate early diagnosis and prognosis refinement, significantly contributing to the management of MHC-II deficiency.

Transient hypogammaglobulinemia of infancy and unclassified syndromic immunodeficiencies are highly common in oesophageal atresia patients.

Due to the high rate of post-operative sepsis and other infectious complications, a routine immunological screening protocol has been initiated since 2015 in our paediatric surgery clinic for all patients admitted with oesophageal atresia (EA) and warrant a delayed definitive treatment. In our study, we aimed to evaluate the immunodeficiencies in EA patients, by comparing them to healthy age-matched controls. As a prospective cohort study, EA patients admitted between 2015 and 2022, who had their definitive operation after the newborn period (>28 days of age) were included. On admission, serum concentrations of IgG, IgA, IgM, lymphocyte subset levels, C3 and C4 levels, specific IgG antibody responses against hepatitis B, hepatitis A, measles, varicella zoster were evaluated. The patients were age-matched with healthy controls to compare the results and followed up until three years of age. If a humoral immunodeficiency was detected, intravenous immunoglobulin treatment was administered before major oesophageal surgery and during follow-up. 31 EA patients (18 M/13F) with a mean age of 13.3 ± 9.0 months were compared with 40 age-matched healthy controls. Mean serum IgG levels were found to be statistically lower than controls in all age groups (P < .05). Transient hypogammaglobulinemia of infancy (THI) and unclassified syndromic immunodeficiencies (USI) were found to be strikingly high, accounting for 29.0% and 22.5%, respectively, adding up to 51.5% of EA patients. This is the first study evaluating immunodeficiencies in EA patients found in the reviewed literature. More than half of EA patients that required delayed surgery had humoral immunodeficiency, so preoperative screening and immunology referral may improve patient outcomes.

Primary immune regulatory disorders (PIRD): expanding the mutation spectrum in Turkey and identification of sixteen novel variants.

Human Inborn Errors of Immunity (IEIs) encompass a clinically and genetically heterogeneous group of disorders, ranging from mild cases to severe, life-threatening types. Among these, Primary Immune Regulatory Disorders (PIRDs) constitute a subset of IEIs characterized by diverse clinical phenotypes, prominently featuring severe atopy, autoimmunity, lymphoproliferation, hyperinflammation, autoinflammation, and susceptibility to malignancies. According to the latest report from the International Union of Immunological Societies (IUIS), PIRDs arise from mutations in various genes including LYST, RAB27A, AP3B1, AP3D1, PRF1, UNC13D, STX11, STXBP2, FAAP24, SLC7A7, RASGRP1, CD70, CTPS1, RLTPR, ITK, MAGT1, PRKCD, TNFRSF9, SH2DIA, XIAP, CD27 (TNFRSF7), FAS (TNFRSF6), FASLG (TNFSF6), CASP10, CASP8, FADD, LRBA, STAT3, AIRE, ITCH, ZAP70, TPP2, JAK1, PEPD, FOXP3, IL2RA, CTLA4, BACH2, IL2RB, DEF6, FERMT1, IL10, IL10RA, IL10RB, NFAT5, TGFB1, and RIPK1 genes. We designed a targeted next-generation sequencing (TNGS) workflow using the Ion AmpliSeq™ Primary Immune Deficiency Research Panel to sequence 264 genes associated with IEIs on the Ion S5™ Sequencer. In this study, we report the identification of 38 disease-causing variants, including 16 novel ones, detected in 40 patients across 15 distinct PIRD genes. The application of next-generation sequencing enabled rapid and precise diagnosis of patients with PIRDs.

Facilitated Subcutaneous Immunoglobulin Treatment Increases the Quality of Life and Decreases the Number of Infections and Hospitalizations in Children with Primary Immunodeficiencies.

INTRODUCTION: Immunoglobulin replacement therapy is an effective lifelong treatment modality used in patients with primary immunodeficiency to prevent and/or reduce the incidence of serious infections. Facilitated subcutaneous immunoglobulin (fSCIG) was developed to combine the advantages of intravenous immunoglobulin (IVIG) and subcutaneous immunoglobulin (SCIG) and is the latest method of immunoglobulin G (IgG) administration. In this study, switching to fSCIG administration in primary immunodeficiency patients receiving regular IVIG or SCIG therapy was evaluated, and serum IgG trough levels, frequency of infections, frequency and duration of hospitalizations, duration of absence from school/work, and quality of life were determined. METHODS: In this study, fifteen patients with primary immunodeficiency who were previously receiving IVIG or SCIG treatment, followed by fSCIG, were evaluated retrospectively. Age, diagnosis, current complications, mean IgG value, frequency of infection, frequency of hospitalization, and duration of absenteeism from school and work were recorded during and before fSCIG treatment. At the beginning of fSCIG treatment, at 6th and 12th months, "The Quality of Life Scale" was also evaluated in patients and parents. RESULTS: The most common indications for initiation of fSCIG treatment were the difficulty of access to the hospital and the long transfusion periods. No systemic adverse reactions were reported except for redness, swelling, and mild pain on the injection site. The median IgG values for the last 1 year were 529.6 mg/dL for IVIG (n = 9), 876.2 mg/dL for SCIG (n = 6) and 856.7 mg/dL for fSCIG (n = 15, all patients) treatment. The frequency of infections and the number of hospitalizations decreased significantly in the fSCIG group compared to both previous treatment modalities. There was a significant increase in the quality of life score of the patients and their families when compared with previous treatment modalities. CONCLUSION: fSCIG is an effective treatment method and is well tolerated in patients with immunodeficiency. It provides stable immunoglobulin levels and excellent protection against infections and offers the patients the possibility of home-based therapy.

Autoimmune Cytopenias Are Highly Associated with Inborn Errors of Immunity and They May Be the Initial Presentations in Cases without Severe Infections.

INTRODUCTION: Inborn errors of immunity (IEIs) are inherited disorders that present with increased susceptibility to infections as well as noninfectious complications. Due to the aberrant immune functions of patients with IEI, autoimmune cytopenia (AIC) may be the initial finding, which makes diagnosis a challenge. We aimed to evaluate the clinical course, laboratory findings, and treatment response of AIC in children with IEI. METHODS: Data of children with autoimmune hemolytic anemia (AIHA) and/or immune thrombocytopenic purpura (ITP) were obtained from a retrospective chart review of IEI patients diagnosed and followed in our center. Demographic and clinical features and therapeutic outcomes were evaluated. Immunologic findings were compared between patients with AIHA, ITP, and Evans syndrome (ES). The patients were also divided into two subgroups based on the presence or absence of immune dysregulation diseases (IDDs), and all data were compared between these two groups. RESULTS: Out of 562 patients with IEI, 6% (n: 34) had AIC which were ITP (23.5%), AIHA (35.5%), and ES (41.2%). AIC was the initial finding in 50% of these 34 patients. Patients with ES had a higher mean percentage of CD8+ T lymphocytes than ITP patients (40.77 ± 20.21% vs. 22.33 ± 12.48%, p = 0.011). Patients with IDDs were more likely to develop ES (p = 0.004), lymphoproliferation (p = 0.005), and resistance to first-line therapy (p = 0.021) than other IEI groups. CONCLUSION: This study shows that AIC may be the initial finding of IEI, particularly when lymphoproliferation and resistance to first-line therapy co-occur. Therefore, detailed investigation should be offered to all patients to avoid diagnostic delay.

Alterations in B and NK cells highly correlate with disease severity in children with COVID-19.

Background/aim: Children with coronavirus disease 2019 (COVID-19) present milder symptoms than adults and are at lower risk of hospitalization and life-threatening complications. However, the kinetics of lymphocyte subsets and serum immunoglobulins in the peripheral blood during COVID-19 infection remains unclear. In this study, it was aimed to determine the changes in hematological and immunological parameters, especially in the lymphocyte subsets, in the peripheral blood of children with different COVID-19 disease severity. Materials and methods: The study was planned as a prospective cohort and included 68 children aged 0-18 years who were admitted to Ege University Faculty of Medicine Department of Pediatrics and diagnosed with COVID-19 infection between May 2020 and December 2021. In addition to demographic characteristics, clinical findings, and severity criteria, hematological, biochemical, and immunological laboratory (T/B lymphocyte subgroups, serum immunoglobulins) results were noted and examined if there were some correlations between disease severity and the laboratory values. Results: In the study group, while 60.6% (n = 40) of the patients received treatment in the hospital, 10.6% (n = 7) needed intensive care treatment. Lymphopenia (35.3%) was more common than neutropenia (14.7%) in the COVID-19-infected children. CD19+ B cells were low in a very high percentage of patients (26.5%), and 16.2% had low levels of NK cells. Significant correlation between disease severity and CD19+lymphocytes, CD19+CD38+IgMlow lymphocytes, CD19+CD38+CD27highIgMhigh lymphocytes, CD19+CD81+ lymphocytes (p = 0.001, p = 0.008, p = 0.014, p = 0.025, and rs = 0.394, rs = 0.326, rs = 0.303, rs = 0.280, respectively), significant inverse correlation between disease severity and absolute lymphocytes counts and CD3-CD16+CD56+ lymphocytes (p = 0.004, 0.014, and rs = -0.353, rs = -0.304, respectively) were observed. The percentage of hospitalized patients with low CD3 levels (15%) was significantly higher than that of the outpatients with low CD3 levels. Conclusion: As the severity of the disease increased, the CD19+, CD19+CD38+IgMlow, CD19+CD38+CD27highIgMhigh, and CD19+CD81+ lymphocytes percentages increased, while the lymphocyte count and NK cell percentage decreased. Therefore, detecting these prognostic immunobiomarkers related to the severity of the disease may contribute considerably to management of the illness.

22q11.2 deletion syndrome: 20 years of experience from two pediatric immunology units and review of clues for diagnosis and disease management

INTRODUCTION AND OBJECTIVES: The purpose of this study was to evaluate patients diagnosed with 22q11.2 deletion syndrome and determine the clues directing to diagnosis and evaluation of immunological findings for excellent management of the disease. MATERIAL AND METHODS: Thirty-three pediatric patients with 22q11.2 deletion syndrome diag­nosed between 1998 and 2019 at Pediatric Immunology Division of Ege University Faculty of Medicine and SBU Izmir Dr Behcet Uz Children's Education and Research Hospital were evaluated. RESULTS: This study includes the largest case series reported from Turkey. Congenital car­diac anomalies were the most common pathology associated with the syndrome (90.9%). Hypocalcemic symptoms were observed in 13 patients (40%). Twenty-two of the 33 (66.6%) patients were diagnosed before two years of age. Autoimmune diseases, dysmorphic facial findings, recurrent infections, growth retardation, and speech impairment were other clues for diagnosis in older patients. Clinical spectrum and immunological abnormalities of this syn­drome are quite variable. All T-cell subset counts were less than 5th percentile below median by age in one patient (3%) and 10 patients had normal all T-cell subset counts (30.3%). Overall, 69.6% of the patients had normal IgG, IgA, and IgM levels and two patients had panhypogam­maglobulinemia. Recurrent infections were revealed in 75.7% of the patients during follow-up. CONCLUSIONS: Presence of cardiac anomaly is more helpful in the diagnosis, especially under two years of age. Patients with immunologically high or standard risk did not show any differ­ence in terms of numbers and severity of infections and autoimmunity

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