[Study of in vitro OK432-induced IFN-gamma production in patients with gastric and esophageal cancers: comparison with in vitro skin tests].

In the present study, we measured in vitro production of IFN-gamma induced by OK432 in peripheral mononuclear cells (PMC) and investigated the relationship between the skin reaction to Su-Ps, an extract of Streptococcus Pyogenes, and purified protein derivative (PPD) and the productibility of IFN-gamma in patients with gastric and esophageal cancers. PMC isolated with the Ficoll-conray centrifugation technique were adjusted to 10(6) cells/ml in RPMI-1640 medium supplemented with 10% fetal calf serum and incubated over 7 days at 37 degrees C in the presence of OK432 at 0.17 KE/ml in microculture plates. IFN-gamma secreted in the supernatants was measured consecutively during the observation period with radioimmunoassay. The results are summarized as follows. 1. The production of IFN-gamma in PMC from patients with negative skin reaction to Su-Ps and PPD was significantly decreased as compared with the value obtained from patients who were positive in these skin tests (p less than 0.001). 2. In vitro production of IFN-gamma induced by OK432 was significantly correlated with the degree of skin tests to Su-Ps and PPD as well (r = 0.48, r = 0.41, p less than 0.01, respectively). Thus, it is concluded that the assay of IFN-gamma produced in PMC cultures is useful to evaluate the immunological status of patients with cancer.