Effect of sera of patients with genitourinary tract cancers on transformation of lymphocytes stimulated with anti-thymocyte globulin.

Serum from patients with genitourinary cancer was tested for ability to support transformation of autologous or normal lymphocytes stimulated with ATG. Selected for specificity for T-lymphocytes, ATG at times gave a more sensitive indication of a serum defect than did PHA. Although poor transformability in the presence of patient serum suggests an inhibitor, this test cannot rule out the possibility of a limitation of an essential nutrient usually supplied by serum. Presence of inhibitor(s) was more strongly indicated by contrasting transformation of normal lymphocytes with patient serum against a panel of normal sera. The presence of circulating inhibitor(s) was confirmed by demonstrating depression of transformation of normal lymphocytes in complete medium by chromatographic fractions from patient serum that did not support transformation. In several instances, patient serum was more inhibitory of autologous than normal lymphocytes, which suggested an additional way of examining host immune competence.