This study conducted to evaluate the serum CXCL10 levels in H. pylori-infected PU patients [including patients duodenal ulcers (DU) or with gastric ulcer (GU)], H. pylori-infected asymptomatic carriers and to compare the levels of CXCL10 between subjects who infected with CagA+ or CagA- strains to clarify possible association. The gene discussed is S100A8; the disease is duodenal ulcer.