The aim of this study was to explore whether there are any associations between the occurrence of IL-1B-31T/C, IL1RN VNTR alleles, IFNGR1-56C/T, HLA DRB1 alleles, together with blood group and life style factors on the one hand, and the occurrence of H. pylori infection, peptic ulcer and the grade of inflammation, atrophy and intestinal metaplasia (IM) of the gastric mucosa, on the other hand, in a prospective population based cohort in Sweden. The gene discussed is HLA-DRB1; the disease is peptic ulcer disease.