INTERLEUKIN-8 EXPRESSION IN HELICOBACTER-PYLORI INFECTED, NORMAL, ANDNEOPLASTIC GASTRODUODENAL MUCOSA

Aims-To investigate the expression of interleukin-8 (IL-8) in Helicoba cter pylori infected normal and neoplastic gastroduodenal mucosa, and in established gastric cancer cell lines. Methods-Immunofluorescence t echniques were used to localise IL-8 in cryosections of gastric (n = 2 5) and duodenal (n = 17) endoscopic biopsy specimens and in resected g astric tumour tissue samples from 16 patients. Two gastric cancer cell lines (Kato 3 and MKN 45) were examined for IL-8 protein expression b y immunofluorescence and for the presence of IL-8 mRNA by reverse tran scription followed by the polymerase chain reaction (RT-PCR). Results- IL-8 was localised to the epithelium in histologically normal gastric mucosa, with particularly strong expression in the surface cells. IL-8 expression was also a feature of surface epithelium in the duodenal b ulb, but was much reduced in the second part of the duodenum. In chron ic H pylori-associated gastritis gastric epithelial IL-8 expression wa s increased and expression of IL-8 within the lamina propria was evide nt. By contrast, large areas of IL-8 negative epithelium were observed in the body mucosa of a subject with Menetriers disease. In gastric c arcinoma the tumour cells were positive for IL-8. IL-8 was also detect ed by immunofluorescence in unstimulated Kato 3 and MKN 45 cells, and constitutive IL-8 gene expression in these cell lines was confirmed by detection of IL-8 mRNA by RT-PCR. Conclusions-Immunoreactive IL-8, a potent neutrophil chemotactic and activating factor, is present in the epithelium of both normal and inflamed gastric mucosa with increased expression in the latter. There is site dependent variation in epithel ial IL-8 expression within the gastroduodenal mucosa. The expression o f the pro-inflammatory cytokine IL-8 in gastric carcinoma cells may in fluence peritumoural cellular infiltrates.