T and B cells and cell-mediated immunity in mycosis fungoides.

T anb B cells in peripheral blood were evaluated in 13 patients with mycosis fungoides (MF) and in two patients with Sézary's syndrome. T cells were identified by their capacity to bind sheep red blood cells to their surfaces and the B cells were identified by the presence of surface immunoglobulins in immunofluorescence assay. Seven patients with MF and two with Sézary's syndrome were shown to have T-cell values below normal and elevated levels of null cells, i.e., cells with markers for neither T nor B cells. Low T-cell values and elevated Null-cell values were found predominantly in patients with advanced mycosis fungoides (stages III-IV). Furthermore, these patients had impaired cell-mediated immunity, as shown by in vivo skin testing with recall antigens and attempts at sensitization to dinitrochlorobenzene.