[Immunoreactivity and the effect on it of the 3-HAA antigen in patients with gastrointestinal tumors].

3-hydroxyanthranilic acid(3-HAA)-antigen, commonly identifiable in blood serum of gastrointestinal cancer patients was shown to influence immunologic vigor in vitro. Treatment of patients' cultured lymphocytes with 3-HAA-antigen and PHA produced a statistically significant inhibition of blastogenic reaction of lymphocytes. Exposure to the said antigen gave a positive leukocyte migration inhibition test both in patients and controls. Antibodies against 3-HAA-antigen were identified in patients' serum by complement fixation test. Blood serum levels of the said antibodies and IgG were found to be in correlation with blood-3-HAA-antigen concentration. Patients' serum revealed an immunosuppressive activity inhibiting formation of antibody-producing cells to sheep erythrocytes in Jerne assay in mice.