Significance of tumour mass on T-lymphocyte levels in patients with gastrointestinal cancer.

The relationship between tumour load and immunity in gastrointestinal cancer has been studied by sequential comparison in patients whose tumour has been removed and those whose tumour was found to be inoperable. Total lymphocyte count, absolute and percentage T- and B-lymphocyte counts, effect of papain on E-rosetting cell levels, and inhibitory effect of cancer sera on E-rosette formation by normal lymphocytes have been studied in 30 patients with stomach or colorectal cancer, and 10 control patients with benign gastrointestinal disease. The examination was done on each patient before and at regular intervals after operation up to 24 weeks. Operable cases, with removal of tumour load, showed a temporary fall in total lymphocyte count and T cell counts, which returned to normal by four weeks postoperatively. Inoperable cases (15 patients) showed a progressive fall in total lymphocyte count and a relatively greater depression of T cell counts, in parallel with increasing tumour mass. E-receptor blocking factor was demonstrated in the sera of cancer patients. This factor was related to tumour mass and presumably was of tumour origin, as it persisted in the inoperable group but disappeared by 12 weeks after tumour removal. The factor explained the excess depresion of T cells over total lymphocytes, but does not explain the continuing depression of total lymphocyte count in the cancer patients.