Rosette-formation with mouse erythrocytes: VI. T, B, and third population lymphoid cells in mycosis fungoides and effect of leukopheresis.

Peripheral blood from 16 patients with mycosis fungoides and two patients with Sézary syndrome was examined for T, B, and third-population (K) cells, using a battery of surface markers. T lymphocytes as determined by spontaneous rosette formation with sheep erythrocytes and third-population cells as determined by the Ripley rosette test were present in normal proportions. Surprisingly, B lymphocytes, as determined by surface immunoglobulin and receptors for mouse erythrocytes, were either lacking or were present in low proportions in some patients. Normal proportions were present in others. Repeat studies of two of three patients lacking B lymphocytes, following treatment, revealed normal or low proportions of B cells. Two patients with mycosis fungoides had increased proportions of "null" cells. Study of lymphoid cell subpopulations before and after leukopheresis in a single patient demonstrated a decrease in T cell proportions associated with a concomitant increase in the proportions of "null" cells following this therapy.