Some reports have provided evidence for ceramide inducing cellular apoptosis whereas others have implicated ceramide in promoting signals for cellular growth and survival.2 Notably, CD8+ T cells from acid sphingomyelinase deficient patients as well as knock-out mice have previously been reported to display defective killing of target cells and impaired control of viral infections,3 leading the authors to generally conclude that acid sphingomyelinase is required for effective secretion of cytotoxic granule content and lymphocyte-mediated target cell killing. The gene discussed is SMPD1; the disease is viral infectious disease.