GC-independent generation of natural effector and CD27⁻IgA⁺ memory B cells. (A) Memory B-cell subset distribution was analyzed in 5 CD40L-deficient patients (age, 1-13 years) and 50 healthy controls (age, 1-5 years). Representative FACS plots of B-cell subsets. (B) Absolute cell numbers of 6 memory B-cell subsets. Bars represent mean values with SEM. Statistical significance was calculated with the Mann-Whitney test. * P < .05, **P < .01, ***P < .001.