Study of naïve and switched memory B cell level in Egyptian patients with common variable immunodeficiency.

Common variable immunodeficiency (CVID) is one of the primary immunodeficiency disorders. The phenotype of peripheral blood memory B cells is a useful tool in the classification of patients into clinically and functionally relevant groups. This study aimed to assess the level of naïve and switched memory B cells level and their correlation with the clinical phenotypes and complications in patients with CVID. This case control study included 30 adult patients with CVID and 30 normal controls, matched for age and sex. Complete blood count, cluster of differentiation 3 (CD3)+, CD4+, CD8+ T cells and CD19+27-IgD+ for naïve B cells and CD19+27+IgD- switched memory B cells levels were assessed. The mean age of the onset of symptoms was 16.9±15.1 years, the mean age of diagnosis was 27.30±14.39 years, with a diagnostic delay of 10.43±10.29 years, and the body mass index was significantly lower in CVID group. Infections including (upper respiratory tract infection, chronic diarrhea, pneumonia and bronchiectasis) were the most frequent phenotypes. CD4+, CD4+/CD8+ T cells, CD19+ and CD19+27+IgD- switch memory B cell, IgG, IgA, and IgM were significantly lower in CVID group than in the control group (p < 0.001 and p < 0.015, respectively). CD8+ T cells and CD19+27-IgD+ naïve B cells were significantly higher in the CVID group (p < 0.001). CD19+27-IgD+ naïve B cells level was significantly lower in cases with bronchiectasis with low baseline serum IgG in lymphadenopathy group (p=0.049), and higher level of CD3+ T cells in cases with splenomegaly. There was no significant difference in laboratory results in CVID patients presented with autoimmune diseases, Granulomas nor enteropathy. In conclusion, high level of CD19+27-IgD+ naïve and low level of CD19+27+IgD- switch memory B cells are characteristic features of CVID. Moreover, the reduced CD19+27-IgD+ naïve B cells level can be a predictor of the development of bronchiectasis in CVID patients.