Serial immunological testing in patients with gastric cancer

Standard immunological parameters measuring non-specific cellular immune reactivity were determined in 175 patients with different stages of gastric cancer prior to surgery and during follow-up. Several tests measuring monocyte activity were also employed. The total number of T cells and their subpopulations Ta and T29° was unchanged except depression of T29° in stage IV. The blastogenic response of lymphocytes to PHA as assessed by stimulation of protein synthesis was only depressed in stage IV. In contrast the PHA-induced lymphokine production was increased in all patients but the differences were significant for stage III and IV. Monocyte Fc receptor expression was increased in stages II-IV, while nitro blue tetrazolium reduction and antibody dependent cellular cytotoxicity of monocytes was elevated in stage IV. The number of extractable monocytes was not increased. Longitudinal studies suggested that most of the parameters normalized during follow-up. No major long-term impact of chemoimmunotherapy (5-FU+BCG) on the immune parameters was observed except a transient increase in PPD reactivity approximately 1 year after commencement of treatment. In patients with stage III gastric cancer the increased occurrence of suppressor cells (mostly monocytes) and elevated cytostatic activity of monocytes was associated with a longer survival while the increased lymphokine production and Fc receptor expression were seen in the group of patients succumbing earlier. We concluded that most of the changes in immune parameters were seen only in advanced disease and paradoxically disappeared in the course of disease. The determination of monocyte activity seems to be a sensitive indicator of immune system dearrangements in earlier stages of cancer and a useful prognostic factor in gastric cancer.