Lack of functional immunoregulatory cells in a patient with mycosis fungoides and circulating Sézary cells.

Peripheral blood lymphocytes obtained at various intervals from normal individuals and from a patient with mycosis fungoides (MF) were cultured with phytohemagglutinin (PHA) for 3 days to activate suppressor cells. After being cultured, the PHA-treated cells were irradiated, washed, and then transferred to fresh medium with PHA. The PHA responsiveness of the cells from normal individuals was suppressed approximately 90% by autologous or normal allogeneic lymphocytes activated for 3 days with PHA, whereas the cells activated for 3 days with PHA from the patient with MF lacked the capacity to inhibit the mitogenic response of autologous or allogeneic lymphocytes. These data suggest that this patient lacked suppressor T-cells that have a specificity for helper T-cells.