Suppressor cells in healthy relatives of patients with hereditary colon cancer.

Patients with sporadic or hereditary colon cancer (cancer family syndrome) demonstrate in vitro defects of cellular immunity characterized by decreased lymphocyte responsiveness in mixed leukocyte culture, which can frequently be attributed to the influence of suppressor macrophages. Healthy relatives of affected patients with hereditary colon cancer can show the same defects of cellular immunity. Affected members with polyposis coli or healthy relatives do not show these defects, whereas individuals with Gardner's syndrome can. These defects of cellular immunity may be an important etiologic component of, or marker for, the cancer family syndrome. These defects could also serve to differentiate the colonic polyposis syndromes.