[Detection of complement-binding immune complexes by means of 51Cr-labeled indicator cells--a new radioimmunoassay (author's transl)].

A new radioimmunoassay for the detection of complement-binding immune complexes is described. The method is based on the ability of the complexes to bind added guinea pig complement (Clq-Component) so that is not available for lysis of 51Cr-labeled chicken red blood cells in a haemolytic system. Sera from 45 patients with malignant tumours, 20 patients with nonmalignant diseases were studied for the presence of circulating immune complexes. The complement-binding capacity of the sera of patients with significantly greater than that of control sera.