Figure 2. TACI mutation(s) result in selective defects for in vitro naive B cell activation.

Purified naive B cells from representative individuals with and without TACI mutation(s) (thick lines) displayed decreased CD86 (A) but mostly normal CD69 (B) induction compared with healthy controls (thin lines) after 48 hours of stimulation with F(ab′)₂ anti-IgM, CpG, and gardiquimod, but not CD40L. CVID patients without TACI mutation(s) (thick lines) displayed more variable CD86 and CD69 induction under activating conditions. Unstimulated healthy controls (dashed line) are shown for comparison. CVID patients (n = 3) and healthy subjects (n = 5) with a single TACI mutation were pooled because they displayed similar decreased B cell responses. Bar graphs (right) represent the combined data from multiple B cell activation experiments. Error bars represent the mean ± SEM. Statistical significance is indicated by an unpaired Student’s t test.