Resistance of lymphoma cells to Fas-induced apoptosis.

Cell suspensions prepared from a lymphomatous lymph node from NIH ALPS proband 55 were subjected to apoptosis induction either via antibody cross-linking of Fas or by 5 μg/mL staurosporine that induces apoptosis by the mitochondrial pathway. The percentages of cells dying are compared with the results with resting lymph node (RLN) cells from patient 55, with cells from a family 17 ALPS patient, with Jurkat T-lymphoma cells, with KK124B Burkitt lymphoma cells, and with normal human tonsil cells. Flow cytometry analysis showed that lymphoma cells from patient 55 were of large size and exhibited B-cell markers and that both the lymphoma cells and the smaller resting lymphocytes expressed normal levels of the Fas receptor on the cell surface.