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

We have evaluated the peripheral blood natural killer (NK) cell activity and the in vitro effect of recombinant gamma-interferon (r gamma-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 less than 0.05) and the gastrinoma patients (p less than 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. r gamma-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.

Influence of sulphasalazine and mesalazine on cellular and biochemical oxygen metabolite production. Effect of in vivo administration and an in vitro analysis.

Oxidative damage has been implicated in the pathogenesis of inflammatory bowel disease. In the present study sulphasalazine and mesalazine (5-aminosalicylic acid) in vitro were shown to possess scavenging activity and to attenuate the production of oxygen metabolites by neutrophils. In a double-blind randomized crossover study, with five patients with inflammatory bowel disease in remission and four healthy controls, we evaluated the influence of in vivo administration of sulphasalazine and mesalazine on the neutrophil oxygen metabolite production in vitro. Apart from a small but significant increase in the neutrophil H2O2 and O2 production by sulphasalazine, in particular in controls, in vivo administration of both drugs hardly affected the oxygen metabolite-producing capacity of the cells. This observation was confirmed by in vitro preincubation of neutrophils with the drugs and subsequent oxygen metabolite production analysis. It is concluded that sulphasalazine and mesalazine do not influence the oxidative capacity of neutrophils, but scavenge and attenuate the production of oxygen metabolites when present in the immediate surroundings of the cells. Thus, protection against oxidative damage is definitely one of the modes of action of these drugs.

Modulatory effects of VIP and related peptides from the gastrointestinal tract on cell mediated cytotoxicity against tumour cells in vitro.

In the present study the effect of vasoactive intestinal peptide (VIP), peptide histidine-methionine (PHM), and secretin on spontaneous cell mediated cytotoxicity of peripheral blood mononuclear cells against tumour target cells was evaluated. VIP stimulated cytotoxicity against CaCo-2 human colon cancer cells, whereas less effect was seen against K-562 erythroleukemia cells. Depletion of CD16+ natural killer cells almost completely abolished cytotoxicity and subsequent VIP incubation did not change residual activity. In contrast to PHM, which hardly influenced cytotoxicity, secretin was found to be more effective especially against K-562 target cells. These observations suggest a modulating role for the neuropeptide VIP in the cellular immune response against tumour cells, especially from the colon, resulting in increased activity of CD16+ natural killer cells. Secretin, seems to be less potent in modulating cellular cytotoxicity. These findings support the concept that gastrointestinal peptides can play a role in the regulation of cellular cytotoxicity against tumor cells.

Natural killer cell activity in patients with adenocarcinoma in the upper gastrointestinal tract.

Natural killer (NK) cell activity and the in vitro effect of recombinant gamma interferon (r gamma-IFN) were evaluated in 12 patients with esophageal adenocarcinoma, 14 patients with gastric adenocarcinoma, 12 patients with pancreatic adenocarcinoma, and 19 healthy controls against the erythroleukemia cell line K-562. Patients with upper gastrointestinal tract carcinomas had a similar spontaneous NK cell activity as the control group. After stimulation with r gamma-IFN, however, the NK cell activity of patients with esophageal or pancreatic adenocarcinoma was significantly lower than that of patients with gastric carcinoma and that of the controls (p less than 0.05). When all patients with adenocarcinomas were classified according to the advancement of the disease, a marked impairment of NK cell activity was found in patients with advanced disease (p less than 0.01) compared to the patients with localized disease or to the controls. Although r gamma-IFN stimulated the NK cell activity of both patients and controls significantly, 62% of the patients with carcinoma and advanced disease remained below the normal spontaneous NK cell activity level even after r gamma-IFN stimulation. In conclusion, an impaired NK cell activity was found in patients with esophageal or pancreatic cancer. Patients with advanced disease were more likely to have an impaired NK cell activity than those with localized disease. The decreased NK cell activity, in particular of patients with esophageal or pancreatic carcinoma, may be related to the unfavourable prognosis of these patients.

Inhibition of cell mediated cytotoxicity by sulphasalazine: effect of in vivo treatment with 5-aminosalicylic acid and sulphasalazine on in vitro natural killer cell activity.

Decreased cell mediated cytotoxicity occurs frequently in inflammatory bowel disease, particularly in patients with active disease. It is not clear, however, whether this decrease is caused by the disease or is a consequence of the medical treatment. In this study we evaluated the effect of in vivo treatment with 5-aminosalicylic acid and sulphasalazine on the in vitro natural killer cell activity in five patients with inflammatory bowel disease in remission and in four healthy control subjects in a double blind randomised crossover trial preceded and separated by four weeks of treatment with placebo. The natural killer cell activity was significantly impaired in 67% (six of nine subjects) after four weeks' sulphasalazine treatment and tended to be related to subjects with a slow acetylator phenotype. In contrast, 5-aminosalicylic acid treatment caused only a marginal reaction in the natural killer cell activity in 22% (two of nine subjects). The inhibitory effects were found to be reversible since the decreased natural killer cell activity was completely restored after placebo treatment in all subjects. In conclusion, in vivo treatment with sulphasalazine inhibits the in vitro natural killer cell activity and this seems to be mediated by the sulphapyridine moiety. This phenomenon may contribute to the low natural killer cell activity found in patients with active inflammatory bowel disease.

Decreased natural killer cell activity in late-onset hypogammaglobulinaemia.

1. Natural killer cell activity and monocyte cytotoxicity was evaluated in three subgroups of patients with primary hypogammaglobulinaemia (ten patients with late-onset, eight with X-linked and five with early-onset disease) and in two patients with secondary late-onset hypogammaglobulinaemia against the K-562 erythroleukaemia, the CaCo-2 colon carcinoma and the HGT-1 gastric carcinoma cell lines and compared with the results found in healthy control subjects. 2. The natural killer cell activity, both spontaneous and after stimulation with recombinant gamma-interferon, was found to be decreased in patients with late-onset hypogammaglobulinaemia. The natural killer cell activity in this subgroup was found to be impaired in 60% of the patients (P less than 0.05). Within the other forms of primary hypogammaglobulinaemia a decreased natural killer cell activity was found to be less frequent (33%). 3. The lectin-mediated cytotoxicity by phytohaemagglutinin resulted in a similar maximal cytotoxicity in patients and control subjects. 4. The cytotoxicity of monocytes, spontaneous and after recombinant gamma-interferon stimulation, was found to be normal in all patients with hypogammaglobulinaemia. 5. The impaired natural killer cell activity which was found in patients with late-onset hypogammaglobulinaemia may contribute to the increased susceptibility to infections and to the increased incidence of malignancies in this subgroup of patients with primary hypogammaglobulinaemia.

In vitro cellular cytotoxicity in Crohn's disease and ulcerative colitis: relation with disease activity and treatment, and the effect of recombinant gamma-interferon.

In a previous study using total mononuclear cells and lymphocytes, enriched by elutriation centrifugation, of patients with Crohn's disease and ulcerative colitis were found to have a decreased NK cell activity. In the present study the relation with disease activity and treatment, and the effect of recombinant gamma-interferon (gamma-IFN) on NK cell and monocyte cytotoxicity has been studied in 19 patients with Crohn's disease, 11 with ulcerative colitis, two with indeterminate colitis and 12 healthy controls. Patients with active Crohn's disease and active ulcerative colitis were shown to have an impaired NK cell activity compared to the control group. However, no difference was found in the percentage of CD16 (Leu 11+) cells, as determined by fluorocytometry, between patients with active or inactive disease. Moreover, the NK cell impairment was not related to corticosteroid treatment. Recombinant gamma-interferon (gamma-IFN) stimulated significantly the cytotoxic activity of the total mononuclear cells and the monocyte-enriched fraction against all target cell lines, both in patients and controls. No relation was found between the increase in cytotoxicity by gamma-IFN and disease activity in the patients. Stimulation with gamma-IFN demonstrated that the monocyte cytotoxic response of inflammatory bowel disease patients is normal. The present study reveals that the impairment in NK cell activity in patients with inflammatory bowel disease is related to disease activity and therefore suggests to be secondary to the inflammatory process.

Natural, lectin- and phorbol ester-induced cellular cytotoxicity in Crohn's disease and ulcerative colitis.

Cellular cytotoxicity of peripheral blood cells was studied in patients with Crohn's disease or ulcerative colitis and healthy controls. The spontaneous cytotoxicity or natural killer (NK) cell activity, evaluated against the erythroleukemia K-562 and the colon cancer CaCo-2 and HT-29 cell lines, of total mononuclear cells and enriched lymphocytes was depressed in Crohn's disease and ulcerative colitis patients compared to the controls. Phytohaemagglutinin (PHA) increased the cytotoxicity in the patients, to a similar maximal level as the stimulated controls. In contrast, the phorbol ester, phorbol-myristate-acetate (PMA), enhanced the cytotoxicity in patients and in controls, but in the patients not to the levels of the controls. No cytotoxicity was observed in the monocyte-enriched fraction both in patients and controls using the same assay system. A similar small but significant stimulation of monocyte cytotoxicity was obtained by PHA and PMA in patients and in controls. In conclusion, inflammatory bowel disease is associated with a depressed NK cell activity in peripheral blood which is not target specific. PHA but not PMA could restore the deficient NK cell activity. Monocytes seem not to be involved in the decreased NK cell activity in patients with inflammatory bowel disease.