APO-1/Fas expression on cells can be induced by cytokines like IFN-γ and TNF-α.[31] Increased expression of mFas has been reported in SLE,[32] MS,[33] chronic adult t-cell leukemia,[34] sarcoidosis,[35] hepatitis B[36] and hepatitis C[37] infections. The gene discussed is FAS; the disease is hepatitis C virus infection.