Cell death induction by several stimuli in T cells from patients with ALD, typical chonic ITP, and ALPS, as well as in age-matched normal controls. Anti-Fas MoAb and ceramide displayed decreased capacity to induce cell death in patients with ALD (n = 6) (dotted lines, ▿) and not in patients with typical chronic ITP (n = 10) (continuous lines, ▵) or in normal controls (n = 13) (dashed lines, □). Patients with ALPS (n = 3) (continuous lines, ▪) displayed decreased Fas-induced but normal ceramide-induced cell death. Cell death induced by methyl-prednisolone (PDN) was not different in patients with ALD or ITP or in normal controls. PHA-derived T cells were cultured as reported in Fig 2 for 18 or 48 hours in the presence of either anti-Fas MoAb (1 μg/mL), ceramide (50 μmol/L), or PDN (1 μmol/L). Cell death was then assessed by the trypan blue exclusion test. The stimuli were simultaneously tested in each patient. Results are expressed as means ± SD of the specific cell survival percentage.