Naive CD4+ T cells and recent thymic emigrants in common variable immunodeficiency.

BACKGROUND Common variable immunodeficiency (CVID) comprises a heterogeneous group of disorders classified as predominantly antibody deficiencies. The aim of this study was to analyze levels of naïve CD4+ T cells and recent thymic emigrant (RTE) cells in CVID patients and healthy controls. METHODS Twenty patients with CVID and 20 age- and sex-matched healthy controls were studied. CD4+ T cells were negatively isolated from peripheral blood mononuclear cells by magnetic beads, and cell surface markers (CD45RA, CD62L and CD31) were assessed by flow cytometry. The normal range of naïve CD4+ T cells detected in the control group (33%-63%) was used to classify the CVID patients into 2 groups (< or = 33% and >33% naïve CD4+ T cells). RESULTS Naïve CD4+ T cells (CD45RA+ CD62L+) and RTE cells (CD45RA+CD62L+CD31+) were significantly lower in male CVID patients compared to both female patients and healthy male controls. There were also more male patients in the group with naive CD4+ T-cell levels of 33% or less. Autoimmunity was only observed in this group. CONCLUSIONS Lower numbers of naïve CD4+ T cells and RTE cells in male CVID patients might be due to lower thymic output in these patients. The classification of patients based on naïve CD4+ T cell levels seems to be consistent with clinical features.