Fc gamma and Fc mu receptors in B cell neoplasms. Correlation to the developmental stages.

Membrane receptors for the Fc portions of IgG (Fc gamma receptor) and IgM (Fc mu receptor) on leukemic cells in B cell neoplasms in various developmental stages were studied. In 6 out of 7 patients with B-CLL, leukemic cells had both receptors. In macroglobulinemia, leukemic cells had one or the other of Fc gamma and Fc mu receptors. In plasma cell leukemia and plasmacytoma, malignant cells had neither Fc gamma or Fc mu receptors. The disappearance of Fc receptors appears to be associated with B cell differentiation.