Radioconglutinin-binding azssay for circulating immune complexes: a new method.

A new method for the detection of circulating immune complexes using radiolabelled conglutinin as a marker for complement-bound complexes precipitated in low concentrations (3.5%) of polyethylene glycol is described. The optimal laboratory conditions for the test have been defined and certain limitations studied. The technique is simple with good reproducibility and high degree of specificity. In a double-blind study of eighty-seven samples of sera from normals, patients with glomerulonephritis, post-renal transplantation, rheumatic diseases, breast tumours, multiple sclerosis and infections the method was compared and correlated to the Clq-binding assay and the Raji cell test. The radioconglutinin-binding assay was most discriminative for cases of glomerulonephritis, renel transplantation, breast carcinoma and multiple sclerosis and least for rheumatoid arthritis.