To evaluate the role of cellular immunity in the pathogenesis of advanced gastric cancer (AGC), the immunologic characteristics of tumor-associated lymphocytes in AGC were compared with those of lymphocytes in tuberculous pleurisy. The immune
parameters
of 57 metastatic gastric cancer patients were compared with those of 20 tuberculous pleurisy patients.
1) Natural killer(NK) activity in malignant ascites lymphocytes was lower than that in autologous peripheral blood lymphocytes(A-PBL) for advanced gastric carcinoma patients(p<0.01). In tuberculous patients, however, there was no difference
between NK
activity in pleural effusion and the activity in A-PBL.
2) Phenotypic analysis showed no significant difference in the proportion of A-PBL lymphocytes between and ascites lymphocytes in AGC patients. In tuberculous patients, however, the proportion of lymphocytes expressing NK markers(CD16, CD56, and
CD57)
was significantly lower in the pleural effusion than in the A-PBL.
3) In gastric cancer median survival was longer for patients with NK activity of PBL>5 lytic units(LU) than those with NK activity<50 LU(11 wks vs. 4 wks; p<0.01).
This data suggests that the decreased NK activity in tumor-associated lymphocytes is not due to a blockage in migration of NK cells to the tumor site but is probably associated with the malfunction of NK cells under the influence of the tumor.
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