Classification of Common Variable Immunodeficiency Using Measurement of B-cell Subsets in Moroccan Patients

Abstract

Objective: Common variable immunodeficiency (CVID) is a complex inborn error of humoral immunity with complications of infectious and non-infectious origins. Classifications of CVID patients provide a clearer understanding of the pathogenesis, prediction, and management of non-infectious complications. This study aimed to classify Moroccan CVID patients using B-cell immunophenotyping, based on the European classification (EUROclass). Materials and Methods: We recruited 20 CVID patients fullfilling established diagnostic standards. After collecting clinical and demographic data, we analyzed B-cell subsets by flow cytometry, grouped patients, and assessed the relationship of each group with clinical manifestations. Results: In our cohort, 90% of the patients had a clinical history of respiratory infections. The non-infectious manifestations included splenomegaly, autoimmunity, lymphadenopathy, and granulomatous diseases diagnosed in 50%, 45%, 40%, and 25% of patients, respectively. We observed significant co-occurrence of splenomegaly with autoimmunity and to a lesser extent with granulomatous diseases. Patients had a significant reduction in total, switched memory, marginal zone-like, and plasmablasts, along with a strong increase in the percentage of activated B-cells, suggesting a defect in the late phases of B-cell differentiation. This condition was linked with an increased occurrence of splenomegaly and granulomatous affections. Besides, patients had also an expansion of CD21low B-cells, which was strongly associated with splenomegaly. Conclusion: The classification of the first Moroccan cohort of CVID patients showed agreement with previous results. It suggests the possibility of adopting this approach on a global scale for better diagnosis and follow-up of CVID patients.