Fc and C3 Receptors as Membrane Differentiation Markers of Acute Myelogenous Leukaemia Cells

Abstract

Acute myelogenous leukemia cells (AML) and cells of chronic myelogenous leukemia blast crisis (CGL-CB) [from humans] were examined for the presence of receptors for Fc IgG fragment (FcR), receptors for the complement components (CR1 and CR2) and surface Ig including the L K and .lambda. type chains. The leukemia blasts were poor in receptors and poorly differentiated. As a rule, they contained very small amounts of detectable FcR, CR2 and CR1. Analysis of AML cell populations separated on the discontinuous density gradient revealed that the appearance of FcR was followed by CR2 and CR1. The CGL-CB cells were more differentiated immunologically since, in comparison with the AML cells, in greater percentage they expressed the FcR and the receptors for complement. Assays for surface Ig indicated that they were not an active product of the leukemic blasts but rather exogenous in origin.