Our initial study showed that the naturally processed ligand triggers PI3K and Ca2+ signaling pathways in activated T cells, which then accumulate in the inflamed organs of SLE patients (36); this raises the question of whether all T cells, or only certain Th subsets, respond to s-CD95L and contribute to SLE pathology by accumulating in inflamed organs. The gene discussed is FASLG; the disease is systemic lupus erythematosus.