Increased serum soluble Fas ligand associated with recurrent B-cell non-Hodgkin's lymphoma after autologous peripheral blood stem cell transplantation

Fas-ligand (FasL) is a member of the tumor necrosis factor family and trans mits apoptotic cell death signal by binding to its receptor, Fas. Fast is e xpressed on the cell surface of activated T-cell and natural killer (NK) ce ll. It has been shown that the Fast can be released from the cell surface b y metalloproteinase. The serum soluble Fast (sFasL) is increased in some pa tients with NK cell lymphoma/large granular lymphocytic leukemia. We have r ecently seen a patient with recurrent B-cell lymphoma accompanied with an i ncreased serum sFasL level after autologous peripheral blood stem cell tran splantation. The sFasL was markedly decreased with the tumor regression ind uced by the chemotherapy. We present here the first case of an elevated ser um sFasL level associated with B-cell lineage malignancy and discuss the po ssible clinical value of sFasL.