Natural killer cell activity in patients with neuroendocrine tumours of the gastrointestinal tract; Relation with circulating gastrointestinal hormones

Abstract

We have evaluated the peripheral blood natural killer (NK) cell activity and the in vitro effect of recombinant gamma-interferon (rγ-IFN) on NK cell activity in 23 patients with a neuroendocrine tumour of the pancreas, small intestine or liver, and 23 healthy controls. Patients with a gastrinoma showed a NK cell activity which was not different from that of the control group, whereas patients with another type of neuroendocrine tumour had a decreased NK cell activity compared to the controls (p < 0.05) and the gastrinoma patients (p < 0.02). The impaired NK cell activity in these patients was as such not related to the presence of liver metastasis or performance status of the patients. rγ-IFN significantly stimulated the NK cell activity in patients and controls. However, the cytotoxic response of the patients with a hormone production other than gastrin remained lower than in the two other groups. Follow-up studies in 8 patients showed NK cell activities not to vary with stable disease, to decrease with progressive disease, and to increase with regression of disease. In conclusion, NK cell activity is suppressed in patients with neuroendocrine tumours that produce hormones other than gastrin. This impairment is not related to the presence of metastasis but seems to be related to the course of the disease.