Target genes regulated by CLEC16A intronic region associated with common variable immunodeficiency.

BACKGROUND: CLEC16A intron 19 has been identified as a candidate locus for common variable immunodeficiency (CVID). OBJECTIVES: This study sought to elucidate the molecular mechanism by which variants at the CLEC16A intronic locus may contribute to the pathogenesis of CVID. METHODS: The investigators performed fine-mapping of the CLEC16A locus in a CVID cohort, then deleted the candidate functional SNP in T-cell lines by the CRISPR-Cas9 technique and conducted RNA-sequencing to identify target gene(s). The interactions between the CLEC16A locus and its target genes were identified using circular chromosome conformation capture. The transcription factor complexes mediating the chromatin interactions were determined by proteomic approach. The molecular pathways regulated by the CLEC16A locus were examined by RNA-sequencing and reverse phase protein array. RESULTS: This study showed that the CLEC16A locus is an enhancer regulating expression of multiple target genes including a distant gene ATF7IP2 through chromatin interactions. Distinct transcription factor complexes mediate the chromatin interactions in an allele-specific manner. Disruption of the CLEC16A locus affects the AKT signaling pathway, as well as the molecular response of CD4+ T cells to immune stimulation. CONCLUSIONS: Through multiomics and targeted experimental approaches, this study elucidated the underlying target genes and signaling pathways involved in the genetic association of CLEC16A with CVID, and highlighted plausible molecular targets for developing novel therapeutics.

Renal complications in patients with predominantly antibody deficiency in the United States Immune Deficiency Network (USIDNET).

BACKGROUND: Prior studies have reported that renal insufficiency occurs in a small percentage of patients with predominantly antibody deficiency (PAD) and in about 2% of patients with common variable immunodeficiency. OBJECTIVE: The goal of our study was to understand and evaluate the prevalence and type of renal complications in patients with PAD in the United States Immunodeficiency Network (USIDNET) cohort. We hypothesized that there is an association between certain renal complications and severity of immunophenotype in patients with PAD. METHODS: We performed a query of patients with PAD from the USIDNET cohort with renal complications. Patients with documented renal disease such as chronic kidney disease (CKD), nephrolithiasis, nephritis, and renal failure syndrome were included. We compared immunophenotype, flow cytometry findings, and immunoglobulin levels of patients with PAD accompanied by renal complications with those of the total USIDNET cohort of patients with PAD. RESULTS: We determined that 140 of 2071 patients with PAD (6.8%) had renal complications. Of these 140 patients, 50 (35.7%) had CKD, 46 (32.9%) had nephrolithiasis, 18 (12.9 %) had nephritis, and 50 (35.7%) had other renal complications. Compared with the total USIDNET cohort of patients with PAD, patients with CKD had lower absolute lymphocyte counts, CD3+ T-cell counts, CD4+ T-cell counts, CD19+ B-cell counts, CD20+ B-cell counts, and CD27+IgD- B-cell counts (P < .05 for all). Patients with nephritis had lower absolute lymphocyte counts, CD19+ B-cell counts, CD27+ B-cell counts, and IgE levels (P < .05 for all) than patients with PAD without renal disease. CONCLUSIONS: We determined that 6.8% of the USIDNET cohort of patients with PAD had a documented renal complication. Compared with the overall cohort of patients with PAD, those patients with nephritis and CKD had a more severe immunophenotype.

Interstitial lung diseases (ILD) in common variable immunodeficiency (CVID) patients: a study from Iran.

INTRODUCTION: Interstitial lung disease (ILD) is a prevalent complication in patients with common variable immunodeficiency (CVID) and is often related to other characteristics such as bronchiectasis and autoimmunity. Because the term ILD encompasses a variety of acute and chronic pulmonary conditions, diagnosis is usually based on imaging features. Histopathology is less available. This study was conducted with the aim of investigating the ILD in patients with CVID. MATERIALS AND METHODS: In this retrospective cross-sectional study, sixty CVID patients who referred to the pulmonology and immunodeficiency clinics of Mofid Children's Hospital between 2013 and 2022 were included. The diagnosis of ILD were based on transbronchial lung biopsy (TBB) or clinical and radiological symptoms. The prevalence of ILD in CVID patients was determined. Also, the CVID patients with and without ILD were compared in terms of demographic characteristics, clinical, laboratory and radiologic findings. RESULTS: Among all patients, ten patients had ILD (16.6%). In terms of laboratory parameters, there was a significant difference between platelets in the two groups of CVID patients with and without ILD, and the level of platelets was higher in the group of patients with ILD. Moreover, in terms of clinical symptoms, pneumonia, diarrhea and hepatomegaly were significantly different between the two groups and were statistically higher in the group of patients with ILD (P < 0.05). Autoimmunity and malignancy were not significantly different in two groups. There was a significant difference in, hyperinflation between the two groups of CVID patients with and without ILD, and the frequency of, hyperinflation was higher in the patients without ILD (P = 0.040). CONCLUSION: Understanding the pathogenesis of ILD plays an essential role in revealing non-infectious pulmonary complications that occur in CVID patients. Increasing efforts to understand ILD not only shed light on its hidden pathogenesis and clinical features, but also enhance our understanding of CVID in a broader sense.

Influence of Splenomegaly and Splenectomy on the Immune Cell Profile of Patients with Common Variable Immunodeficiency Disease.

PURPOSE: About 25% of patients with common variable immunodeficiency disease (CVID) have splenomegaly, necessitating sometimes splenectomy whom consequences on the immunological profile of CVID patients have never been studied. We analyzed 11 CVID patients' comprehensive blood immune cell phenotypes pre- and post-splenectomy. METHODS: Flow cytometry analyses of immune cell populations. RESULTS: Among 89 CVID cohort patients, 41 with splenomegaly, splenomegaly was strongly associated with granulomatous disease, autoimmune disorders, lymphoid hyperplasia, and/or portal hypertension. CVID patients with splenomegaly have significant peripheral lymphopenia (p = 0.001), and significantly fewer peripheral class-switched memory B cells (smBs) (p = 0.001), CD4+ T lymphocytes (p = 0.001), NK (p = 0.0001) and dendritic cells (p ≤ 0.01), and significantly more circulating CD4+ and CD8+ (p = 0.00001) T cell subset activation (p = 0.00005), than CVID patients without splenomegaly. Examination of splenectomy impact on circulating lymphocyte subset distributions demonstrated the drastically enhanced total circulating lymphocyte count post-splenectomy, predominantly B lymphocytes and CD8+ T cells. However, splenectomy did not change B cell distribution, with smBs remaining persistently low, in contrast to complete inversion of the circulating T cell composition, with reversal of the CD4+/CD8+ ratio suggesting that amplification of the CD8+ T cell compartment is a CVID characteristic in patients with splenomegaly. Our results highlight this CD8+ amplification in CVID-splenomegaly patients that might be explained by a homing effect to the spleen and/or possible chronic virus replication, which in turn could induce T cell expansions. CONCLUSION: Splenectomizing CVID patients with splenomegaly restores the absolute circulating lymphocyte count, suggesting that the decreased T cell count in the presence of splenomegaly cannot be used as an exclusive criterion for combined immunodeficiency.

Role of Skewed X-Chromosome Inactivation in Common Variable Immunodeficiency.

The term common variable immunodeficiency (CVID) encompasses a clinically diverse group of disorders, mainly characterized by hypogammaglobulinemia, insufficient specific antibody production, and recurrent infections. The genetics of CVID is complex, and monogenic defects account for only a portion of cases, typically <30%. Other proposed mechanisms include digenic, oligogenic, or polygenic inheritance and epigenetic dysregulation. In this study, we aimed to assess the role of skewed X-chromosome inactivation (XCI) in CVID. Within our cohort of 131 genetically analyzed CVID patients, we selected female patients with rare variants in CVID-associated genes located on the X-chromosome. Four patients harboring heterozygous variants in BTK (n = 2), CD40LG (n = 1), and IKBKG (n = 1) were included in the study. We assessed XCI status using the HUMARA assay and an NGS-based method to quantify the expression of the 2 alleles in mRNA. Three of the 4 patients (75%) exhibited skewed XCI, and the mutated allele was predominantly expressed in all cases. Patient 1 harbored a hypomorphic variant in BTK (p.Tyr418His), patient 3 had a pathogenic variant in CD40LG (c.288+1G>A), and patient 4 had a hypomorphic variant in IKBKG (p.Glu57Lys) and a heterozygous splice variant in TNFRSF13B (TACI) (c.61+2T>A). Overall, the analysis of our cohort suggests that CVID in a small proportion of females (1.6% in our cohort) is caused by skewed XCI and highly penetrant gene variants on the X-chromosome. Additionally, skewed XCI may contribute to polygenic effects (3.3% in our cohort). These results indicate that skewed XCI may represent another piece in the complex puzzle of CVID genetics.

Assessment of Sleep Disorders in Patients with CVID.

Inborn errors of immunity have been associated with reduced health-related quality of life and increased fatigue. Sleep disorders, which have been shown to contribute to fatigue and other health concerns, are prevalent in the general population, but there are limited studies evaluating these conditions in patients with common variable immunodeficiency (CVID). Our aim was to evaluate the prevalence of fatigue, sleep disturbances, and sleep-disordered breathing in adults with CVID. Patients completed 4 validated, self-administered questionnaires and a 1-night disposable home sleep apnea test. Our results demonstrated increased median Patient-Reported Outcomes Measurement Information System fatigue scores of 58.7 in patients with CVID in addition to clinically significant fatigue as measured by Fatigue Severity Scale score (median, 5.2) and overall poor sleep quality based on global Pittsburgh Sleep Quality Index score (median, 9.0). For CVID patients who completed the home sleep apnea test, 76.9% met criteria for sleep-disordered breathing with an Apnea-Hypopnea Index score of 5 or greater. The results of our study indicate that patients with CVID may have increased rates of undiagnosed sleep disorders that may contribute to increased fatigue and reduced health-related quality of life.

High Prevalence of Long COVID in Common Variable Immunodeficiency: An Italian Multicentric Study.

The long-term effects of SARS-CoV-2 infection represent a relevant global health problem. Long COVID (LC) is defined as a complex of signs and symptoms developed during or after SARS-CoV-2 infection and lasting > 12 weeks. In common variable immunodeficiency (CVID) patients, we previously reported higher risk of hospitalization and death during SARS-CoV-2 infection, as well as prolonged swab positivity and frequent reinfections. The aim of the present study was to assess the risk of LC in an Italian cohort of CVID patients. We used a translated version of the survey proposed by Centers for Disease Control and Prevention (CDC) to collect data on LC. In the enrolled cohort of 175 CVID patients, we found a high prevalence of LC (65.7%). The most frequent LC symptoms were fatigue (75.7%), arthralgia/myalgia (48.7%), and dyspnea (41.7%). The majority of patients (60%) experienced prolonged symptoms, for at least 6 months after infection. In a multivariate analysis, the presence of complicated phenotype (OR 2.44, 95% CI 1.88-5.03; p = 0.015), obesity (OR 11.17, 95% CI 1.37-90.95; p = 0.024), and female sex (OR 2.06, 95% CI 1.09-3.89; p = 0.024) significantly correlated with the development of LC. In conclusion, in this multicenter observational cohort study, we demonstrated that CVID patients present an increased prevalence of LC when compared to the general population. Improved awareness on the risk of LC in CVID patients could optimize management of this new and alarming complication of SARS-CoV-2 infection.

18q Deletion Syndrome Presenting with Late-Onset Combined Immunodeficiency.

Patients with chromosome 18q deletion syndrome generally experience hypogammaglobulinemia. Herein, we describe two patients with chromosome 18q deletion syndrome who presented with late-onset combined immune deficiency (LOCID), which has not been previously reported. Patient 1 was a 29-year-old male with 18q deletion syndrome, who was being managed for severe motor and intellectual disabilities at the Yamabiko Medical Welfare Center for 26 years. Although the patient had few infections, he developed Pneumocystis pneumonia at the age of 28. Patient 2, a 48-year-old female with intellectual disability and congenital malformations, was referred to Tokyo Medical and Dental University Hospital with abnormal bilateral lung shadows detected on her chest radiography. Computed tomography showed multiple lymphadenopathies and pneumonia. A lymph node biopsy of the inguinal region revealed granulomatous lymphadenitis, and a chromosomal examination revealed 18q deletion. Array-based genomic hybridization analysis revealed deletion at 18q21.32-q22.3 for patient 1 and at 18q21.33-qter for patient 2. Immune status work-up of the two patients revealed panhypogammaglobulinemia, decreased number of memory B cells and naïve CD4+ and/or CD8+ cells, reduced response on the carboxyfluorescein diacetate succinimidyl ester T-cell division test, and low levels of T-cell receptor recombination excision circles and Ig κ-deleting recombination excision circles. Consequently, both patients were diagnosed with LOCID. Although patients with 18q deletion syndrome generally experience humoral immunodeficiency, the disease can be further complicated by cell-mediated immunodeficiency, causing combined immunodeficiency. Therefore, patients with 18q deletion syndrome should be regularly tested for cellular/humoral immunocompetence.

A Cross-Sectional Study of Health-Related Quality of Life in Patients with Predominantly Antibody Deficiency.

Health-related quality of life (HRQoL) measures individual well-being across physical, psychological, and social domains. Patients with predominantly antibody deficiency (PAD) are at risk for morbidity and mortality, however, the effect of these complications on HRQoL requires additional study. Patients with PAD were asked to voluntarily complete the Centers for Disease Control (CDC) HRQoL-14 Healthy Days Measure questionnaire. These results were compared to data from the CDC-initiated Behavioral Risk Factor Surveillance System (BRFSS), a cross-sectional questionnaire including questions from CDC-HRQOL-14. Statistical analyses included two-proportion Z-test, t-tests, and analysis of variance. 83 patients with PAD completed the survey. Patients were sub-stratified into mild (23.7%), moderate (35.5%), severe (40.8%), and secondary (8.4%) PAD. "Fair or poor" health status was reported in 52.6% of PAD patients. Mental health challenges ≥ 14 days/month occurred in 25% of patients. Physical health issues ≥ 14 days/month was reported in 44.7% of patients. Activity limitations were noted by 80.3% of patients. There were no statistically significant differences by PAD severity. Patients with autoimmune and inflammatory disease co-morbidities reported more mental health challenges compared to those without (78% vs. 54.3%, p = 0.02). Compared to the CDC-BRFSS data, significantly more patients with PAD reported "fair or poor" health status (53% vs 12.0%; p < 0.0001), mental health challenges (24.1% vs 14.7%; p = 0.02), and poor physical health (44.6% vs 8.0%; p < 0.0001). Patients with PAD had significantly reduced HRQoL compared to CDC-BRFSS respondents from a similar geographical region. Decreased HRQoL was prevalent across all PAD severity levels. Additional research is needed to improve HRQoL for patients with PAD.

Clinical and experimental treatment of primary humoral immunodeficiencies.

Selective IgA deficiency (sIgAD), common variable immunodeficiency (CVID), and transient hypogammaglobulinemia of infancy (THI) are the most frequent forms of primary antibody deficiencies. Difficulties in initial diagnosis, especially in the early childhood, the familiar occurrence of these diseases, as well as the possibility of progression to each other suggest common cellular and molecular patomechanism and a similar genetic background. In this review, we discuss both similarities and differences of these three humoral immunodeficiencies, focusing on current and novel therapeutic approaches. We summarize immunoglobulin substitution, antibiotic prophylaxis, treatment of autoimmune diseases, and other common complications, i.e. cytopenias, gastrointestinal complications, and granulomatous disease. We discuss novel therapeutic approaches such as allogenic stem cell transplantation and therapies targeting-specific proteins, dependent on the patient's genetic defect. The diversity of possible therapeutics models results from a great heterogeneity of the disease variants, implying the need of personalized medicine approach as a future of primary humoral immunodeficiencies treatment.

Evaluation of the Effectiveness of the 6 Warning Signs of the European Society for Immunodeficiencies for Primary Immunodeficiencies in Older Adults.

INTRODUCTION: Diagnostic delay in cases of primary immunodeficiency (PID) is a significant problem for clinicians, and most do not have sufficient awareness of this uncommon disorder. The European Society for Immunodeficiencies (ESID) has developed 6 warning signs to increase awareness of adult PIDs. The aim of this study was to determine the prevalence of PID in older adults regardless of the reason for presentation and to evaluate the effectiveness of the 6 warning signs of ESID in the diagnosis of PIDs. METHODS: The study included 1,331 patients aged ≥65 years who presented at our clinic for any reason and were questioned about the ESID 6 warning signs for PIDs. After the exclusion of reasons for secondary immunodeficiency (SID), all the patients underwent immunological evaluation for the diagnosis of potential underlying PIDs. RESULTS: After excluding 6 patients diagnosed with SID, PID was diagnosed in 16 (1.2%) of 1,325 older adults using ESID warning signs. The most common reasons for presentation were infection (69%) in the PID group and urticaria and/or angioedema (41.5%) in the non-PID group. The most common PID subgroup was common variable immunodeficiency (50%). In 12 of the patients diagnosed with PID, there was at least 1 positive ESID warning sign. In 4 patients, PID was determined despite negative ESID warning signs. The patients diagnosed with PID showed a significant, minimal level of agreement with questions 1 and 4 of the ESID warning signs (p < 0.001, ĸ = 0.204, p = 0.005, ĸ = 0.208, respectively). CONCLUSION: The ESID warning signs do not encompass all the symptoms and findings of PIDs. There is a need for more infection-centered questions to determine PIDs in older adults. Therefore, the ESID warning signs should be further developed.

Shorter antitubercular therapy for extrapulmonary tuberculosis - a case report.

INTRODUCTION: Extrapulmonary tuberculosis (EPTB) adds to India's significant economic burden, with pericardial effusion being a potentially fatal complication. This case report highlights the need for early diagnosis and the feasibility of shorter-duration treatment for EPTB in developing countries. PRESENTATION: This case report describes a 19-year-old male from Southeast Asia who had a history of bronchiectasis involving the left lower lobe and the right middle lobe, which was cystic in nature, as well as multiple episodes of non-tuberculous pneumonia. Currently, he presented with fever, hypotension, tachycardia, and acute kidney injury. Echocardiogram showed left ventricular dysfunction with a left ventricular ejection fraction (LVEF) of 45% and moderate pericardial effusion. Early signs of cardiac tamponade were noted, specifically the absence of respiratory variation in the right ventricle and left ventricle collapse. Emergent pericardiocentesis was performed, and hemorrhagic pericardial fluid was aspirated. Fluid analysis revealed high levels of LDH (5000 U/L), polymorphonuclear leukocytosis, and acid-fast bacilli that were visualized on microscopy, which led to the diagnosis of pericardial tuberculosis. A CT of the abdomen showed hepatosplenomegaly and polyserositis. Empirically, antitubercular therapy consisting of isoniazid, rifampin, pyrazinamide, and ethambutol was administered for 2 months and isoniazid along with rifampicin was given for the next 4 months. Serial echocardiograms in the following months showed an improvement in LVEF (55%) and decreased effusion. However, during this treatment period, due to frequent episodes of pneumonia, the evaluation of immunodeficiency disorders was performed and revealed low levels of IgG (4.741 g/L), IgA (0.238 g/L), and IgM (0.098 g/L). He was diagnosed with common variable immunodeficiency disease and received intravenous immunoglobulin therapy. CONCLUSION: This report emphasizes the timely identification of cardiac tamponade and the effective management of EPTB through a shorter-than-recommended course of antitubercular therapy, resulting in the alleviation of symptoms and better overall health outcomes.

Noninfectious Complications in B-Lymphopenic Common Variable Immunodeficiency.

BACKGROUND: Common variable immunodeficiency (CVID) is considered the most symptomatic type of inborn errors of immunity in humans. Along with infectious complications, which have numerous consequences, noninfectious complications are a major challenge among CVID patients. METHODS: All CVID patients registered in the national database were included in this retrospective cohort study. Patients were divided into 2 groups based on the presence of B-cell lymphopenia. Demographic characteristics, laboratory findings, noninfectious organ involvement, autoimmunity, and lymphoproliferative diseases were evaluated. RESULTS: Among 387 enrolled patients, 66.4% were diagnosed with noninfectious complications and 33.6% with isolated infectious presentations. Enteropathy, autoimmunity, and lymphoproliferative disorders were reported in 35.1%, 24.3%, and 21.4% of patients, respectively. Some complications, including autoimmunity and hepatosplenomegaly, were reported to be significantly more frequent among patients with B-cell lymphopenia. As for organ involvement, the dermatologic, endocrine, and musculoskeletal systems were predominantly affected in CVID patients with B-cell lymphopenia. Among autoimmune manifestations, the frequency of rheumatologic, hematologic, and gastrointestinal autoimmunity was reported to be higher than that of other types of autoimmunity not associated with B cell-lymphopenia. Furthermore, hematological cancers, particularly lymphoma, were the most common type of malignancy. The mortality rate was 24.5%, and respiratory failure and malignancies were the most common causes of death, with no significant differences between the 2 groups. CONCLUSIONS: Considering that some of the noninfectious complications might be associated with B-cell lymphopenia, regular patient monitoring and follow-up with proper medication (in addition to immunoglobulin replacement therapy) are highly recommended to prevent sequelae and increase patient quality of life.

TCF3 haploinsufficiency defined by immune, clinical, gene-dosage, and murine studies.

BACKGROUND: TCF3 is a transcription factor contributing to early lymphocyte differentiation. Germline monoallelic dominant negative and biallelic loss-of-function (LOF) null TCF3 mutations cause a fully penetrant severe immunodeficiency. We identified 8 individuals from 7 unrelated families with monoallelic LOF TCF3 variants presenting with immunodeficiency with incomplete clinical penetrance. OBJECTIVE: We sought to define TCF3 haploinsufficiency (HI) biology and its association with immunodeficiency. METHODS: Patient clinical data and blood samples were analyzed. Flow cytometry, Western blot analysis, plasmablast differentiation, immunoglobulin secretion, and transcriptional activity studies were conducted on individuals carrying TCF3 variants. Mice with a heterozygous Tcf3 deletion were analyzed for lymphocyte development and phenotyping. RESULTS: Individuals carrying monoallelic LOF TCF3 variants showed B-cell defects (eg, reduced total, class-switched memory, and/or plasmablasts) and reduced serum immunoglobulin levels; most but not all presented with recurrent but nonsevere infections. These TCF3 LOF variants were either not transcribed or translated, resulting in reduced wild-type TCF3 protein expression, strongly suggesting HI pathophysiology for the disease. Targeted RNA sequencing analysis of T-cell blasts from TCF3-null, dominant negative, or HI individuals clustered away from healthy donors, implying that 2 WT copies of TCF3 are needed to sustain a tightly regulated TCF3 gene-dosage effect. Murine TCF3 HI resulted in a reduction of circulating B cells but overall normal humoral immune responses. CONCLUSION: Monoallelic LOF TCF3 mutations cause a gene-dosage-dependent reduction in wild-type protein expression, B-cell defects, and a dysregulated transcriptome, resulting in immunodeficiency. Tcf3+/- mice partially recapitulate the human phenotype, underscoring the differences between TCF3 in humans and mice.

Heterozygous SERPINA1 Defects and Their Impact on Clinical Manifestations of Patients with Predominantly Antibody Deficiencies.

Patients with predominantly antibody deficiencies (PADs) display hypogammaglobulinemia with a high prevalence of infections, along with autoimmune manifestations, benign and malignant lymphoproliferation and granulomatous disease. It is noteworthy that PAD patients, even those with defects in the same causative genes, display a variable clinical phenotype, suggesting that additional genetic polymorphisms, located in either immune-related or non-immune-related genes, may affect their clinical and laboratory phenotype. In this context, we analyzed 80 PAD patients, including 70 with common variable immunodeficiency (CVID) for SERPINA1 defects, in order to investigate the possible contribution to PAD clinical phenotype. Ten CVID patients carried heterozygous pathogenic SERPINA1 defects with normal alpha-1 antitrypsin levels. Interestingly, the presence of the Z allele (rs28929474), which was found in three patients, was significantly associated with liver disease; hepatic complications were also observed in patients carrying the p.Leu23Gln (rs1379209512) and the p.Phe76del (rs775982338) alleles. Conversely, no correlation of SERPINA1 defective variants with respiratory complications was observed, although patients with pathogenic variants exhibit a reduced probability of developing autoimmune diseases. Therefore, we recommend SERPINA1 genetic analysis in PAD in order to identify patients with a higher risk for liver disease.

The Horse with Recurrent Fevers and Infections: Approach to Common Variable Immunodeficiency.

Equine common variable immunodeficiency (CVID) is a rare, late-onset, nonfamilial humoral deficiency characterized by B-cell depletion and/or dysfunction resulting in inadequate antibody production and predisposition to recurrent infections. Serum immunoglobulin concentration and peripheral blood lymphocyte immunophenotyping are required to diagnose and characterize CVID in horses. Early recognition of the disease by the equine practitioner is paramount to managing the quality of life for these patients, for whom specific treatment is not yet available and long-term prognosis remains poor. An approach to the diagnosis, identification of complicating factors, and management of horses with CVID are discussed.

Early Onset Inflammatory Bowel Disease Due to Immunodeficiency as a Result of ICOS Gene Homozygous Mutation.

INTRODUCTION: Inflammatory bowel disease (IBD) is classified as very early-onset IBD (VEO-IBD) if it occurs before age six. VEO-IBD may progress with more severe and resistant inflammation findings in the gastrointestinal and non-gastrointestinal systems. CASE REPORT: We describe the clinical presentation of a 4-year-old female presenting with recurring episodes of bloody diarrhea, vomiting, abdominal pain, fever, arthritis, erysipelas, and bilateral ankle pain. Monogenic primary immunodeficiency (PID) was suspected due to her age, different clinical findings and the presence of atypical gastroscopic findings and deep transmural ulcerations resembling Crohn's disease. The gene analysis showed a homozygous mutation in the inducible T cell co-stimulator (ICOS) deficiency genes. DISCUSSION/CONCLUSION: This case presentation shares our clinical experience and demonstrates the link between IBD progression and ICOS deficiency.

Common variable immunodeficiency associated enteropathy: A diagnostic enigma in developing countries.

Common variable immunodeficiency (CVID) is the most prevalent primary immunodeficiency disorder with different phenotypes and aetiologies. It is characterised by hypogammaglobulinaemia, defects in specific antibody response, erroneous activation and proliferation of T cells, leading to increased risk of recurrent infections. In CVID, "Variable" refers to the heterogeneity of clinical presentations, which include recurrent infections, autoimmunity, enteropathy, and increased risk of malignancies. This wide spectrum of disease manifestations and being a diagnosis of exclusion poses a diagnostic challenge. It is pertinent to mention that CVID along with associated complications is the commonest symptomatic primary antibody deficiency but is scarcely mentioned in local literature. The main aim of presenting this case is to impress upon the importance of systematic immunological workup in cases of suspected immunodeficiency to prevent morbidity and mortality.

A Nationwide Study of the Delayed Diagnosis and the Clinical Manifestations of Predominantly Antibody Deficiencies and CTLA4-Mediated Immune Dysregulation Syndrome in Greece.

Background and Objectives: Predominantly antibody deficiencies (PAD) represent the most common type of primary immunodeficiencies in humans, characterized by a wide variation in disease onset, clinical manifestations, and outcome. Considering that the prevalence of PAD in Greece is unknown, and there is limited knowledge on the clinical and laboratory characteristics of affected patients, we conducted a nationwide study. Materials and Methods: 153 patients (male/female: 66/87; median age: 43.0 years; range: 7.0-77.0) diagnosed, and followed-up between August 1979 to September 2023. Furthermore, we classified our cohort into five groups according to their medical history, immunoglobulin levels, and CTLA4-mutational status: 123 had common variable immunodeficiency (CVID), 12 patients with "secondary" hypogammaglobulinemia due to a previous B-cell depletion immunotherapy for autoimmune or malignant disease several years ago (median: 9 years, range 6-14) displaying a typical CVID phenotype, 7 with combined IgA and IgG subclass deficiencies, 5 patients with CVID-like disease due to CTLA4-mediated immune dysregulation syndrome, and 6 patients with unclassified hypogammaglobulinemia. Results: We demonstrated a remarkable delay in PAD diagnosis, several years after the onset of related symptoms (median: 9.0 years, range: 0-43.0). A family history of PAD was only present in 11.8%, with the majority of patients considered sporadic cases. Most patients were diagnosed in the context of a diagnostic work-up for recurrent infections, or recurrent/resistant autoimmune cytopenias. Interestingly, 10 patients (5.6%) had no history of infection, diagnosed due to either recurrent/resistant autoimmunity, or during a work-up of their medical/family history. Remarkable findings included an increased prevalence of lymphoproliferation (60.1%), while 39 patients (25.5%) developed bronchiectasis, and 16 (10.5%) granulomatous disease. Cancer was a common complication in our cohort (25 patients, 16.3%), with B-cell malignancies representing the most common neoplasms (56.7%). Conclusion: Our findings indicate the necessity of awareness about PAD and their complications, aiming for early diagnosis and the appropriate management of affected patients.

Reference values of lymphocyte subsets from healthy Polish adults.

The flow cytometry method could support physicians' decisions in the diagnosis and treatment monitoring of immunodeficient patients. Most clinical recommendations are focused on the search for alterations in T- and B-lymphocyte subsets, less commonly natural killer (NK) cells and granulocytes. While reference values for clinically meaningful lymphocyte subsets have been published ubiquitously among numerous countries, we have not found significant data for a population of adult Polish habitats; thus we determined reference values for T, B, and NK subsets according to sex and age. The female group showed a higher percentage of lymphocytes (CD45++), T helper lymphocytes with a higher absolute count, as well as CD4/CD8 ratio, marginal zone-like B cells, class-switched B cells, and CD21low B cells than the male group. The male group was found to have elevated percentages of naïve B lymphocytes, transitional B cells, and plasmablasts. A weak positive correlation with age was found among double positive T lymphocytes, natural killer T cells (NKT) lymphocytes, and CD21low B cells. A negative correlation with age for double negative T lymphocytes, marginal zone-like B cells, and plasmablasts was noted. The results indicated the importance of creating distinct reference ranges regarding sex and age concerning immunophenotype.