Lymphocyte apoptosis in periodic fever patients. Apoptosis of lymphocytes is expressed as a percentage of annexin-V–positive lymphocytes (PI negative); white bars represent controls, black bars patients. (A) Patients with HIDS versus controls without anisomycin stimulation; neither group shows apoptosis. (B) Incubation of lymphocytes with anisomycin results in a significant increase of apoptosis after 24 hours when compared with unstimulated lymphocytes in both controls (P < .001) and patients (P = .005), but the increase in HIDS lymphocytes is significantly less than in controls (P < .001). Lymphocytes from patients with (C) TRAPS or (D) FMF show as much apoptosis as controls. (*P = .005; **P < .001). (E) Healthy control (white) versus a patient with HIDS (black) after 24 hours of exposure to anisomycin. Representative result from 10 experiments. (F) Apoptosis of lymphocytes of patients with HIDS expressed as caspase-3/7 activity after 2 hours of anisomycin stimulation. Patients show decreased caspase-3/7 activity compared with controls. Data represent mean values ± standard error of the mean.