Combined decrease of defined B and T cell subsets in a group of common variable immunodeficiency patients

Common variable immunodeficiency disease (CVID) is a primary immune disorder affecting B cells and characterized by hypogammaglobulinemia and recurrent infections. To elucidate the clinical and immunological heterogeneity of this condition, we have studied B and T cell subsets in 25 CVID patients. In eleven of them, we observed a remarkable relative expansion of a B cell subpopulation (CD19hi/CD21lo cells) characterized by the absence of CD23 and the reduced expression of the chemokine receptors CXCR5 and CCR7. Our analyses demonstrated in these patients that the expansion of CD19hi/CD21lo cells correlates with a selective decrease of circulating naïve and CD21hi memory B lymphocytes. The same group of patients displayed a simultaneous severe reduction of naïve CD4+ T cells associated with decreased levels of T cell receptor excision circles. These observations suggest that a combined defect in generation of B and T subpopulations may account for the abnormal immunophenotype characterizing this subgroup of CVID patients.