Incidence of circulating immune complexes in patients with lung cancer and their effect on antibody-dependent cytotoxicity.

Circulating immune complexes were determined in patients with lung cancer by the C1q deviation test and by column chromatography on Sepharose 6 B. Immune complexes could be demonstrated by the two different methods in 50--80% of patients' sera at the time of diagnosis. Patients with extended disease had more immune complexes than patients with limited disease. Serial determinations showed a good correlation between immune complex levels and clinical course of disease. The size of the immune complexes present in patients' sera was determined by sucrose density ultracentrifugation and by column chromatography in the region between 10 S and 30 S. Furthermore in this study no inhibition of antibody-dependent cell-mediated cytotoxicity by circulating immune complexes could be seen.