Incidence of autoantibodies in cancer patients.

A review of the incidence of autoantibodies to normal tissue constituents in 250 patients with malignant disease has shown positive tests in 15% compared with 24% in patients with general non-neoplastic disorders and 8% in normal blood donors. In patients with lymphoma or leukaemia, the incidence of anti-smooth muscle antibodies was 15% compared with 4% in the control population; there was no increase in the incidence of anti-smooth muscle antibodies in patients with other malignant conditions. The incidence of anti-smooth muscle antibody in 4000 sera submitted for the investigation of possible autoimmune disorders is also reviewed. In our hands, autoantibodies to normal tissue components in patients with malignant tumours have not been a significant source of error in laboratory assessment of anti-tumour immunoreactivity.