Increased inflammatory responses of persons of blood group O to Helicobacter pylori.

Persons of blood group O are at increased risk of peptic ulcers. Enhanced binding of Helicobacter pylori to epithelial cells of persons of blood group O has been demonstrated. Release of interleukin (IL)-6, IL-10, and tumor necrosis factor (TNF)-alpha by human leukocytes from 40 donors (10 from each ABO blood group) was measured after incubation in vitro with outer membrane protein preparations of H. pylori. Isolates DU (from a patient with a duodenal ulcer), GC (from a patient with gastric cancer), NE (from a patient with normal endoscopic findings), and NCTC 11637 bound in significantly higher numbers to group O leukocytes. Bacterial binding correlated with release of IL-6 and TNF-alpha but not of IL-10. Group O cells released significantly more IL-6 in response to DU, NE, and NCTC 11637, and the cells released more TNF-alpha in response to DU and NCTC 11637. Increased density of colonization of epithelial cells and higher inflammatory responses to H. pylori of persons of blood group O might contribute to increased susceptibility to peptic ulceration.