Ibrutinib treatment of human T cells protects against activation induced cell death and reduces FAS-L mRNA expression in a dose dependent manor. T cells were isolated from healthy donors blood samples, stimulated in vitro with CD3/CD28 for 3 days, rested for 11 days, then were restimulated with CD3 for 6 hours (as in A. and B.) or 3 hours (as in C.) in the presence of IL2 to induce AICD in the presence or absence of ibrutinib.