Reduced naive CD4+ T cell frequency and absolute count were seen in all subgroups of CVID patients (median cell count: HC = 384 mm3, Freiburg 1a/b = 77 mm3 [p = 0.01], Freiburg 2 = 24 mm3 [p = 0.002]; median frequency: HC = 38.0%, Freiburg 1a/b = 10.9% [p = 0.023], Freiburg 2 = 6.2% [p = 0.029]), with a positive correlation found between naive CD4+ T cells and S.E. repertoire diversity (Fig. 2B, 2C). The gene discussed is CD4; the disease is common variable immunodeficiency.