Fc and C3 receptors as membrane differentiation markers of acute myelogenous leukaemia cells.

Acute myelogenous leukaemia cells (AML) and cells of chronic myelogenous leukaemia blast crisis (CGL-CB) were examined for the presence of receptors for Fc IgG fragment (FcR), receptors for the complement components (CR1 and CR2), and the surface immunoglobulins including the light kappa and lambda type chains. The leukaemia blasts were found to be the cells poor in receptors and poorly differentiated. As a rule, they contained very small amount 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 immunoglobulins indicated that they were not an active product of the leukaemic blasts, but rather exogenous in origin.