We read with great interest the article by

) on the influence of cytokine gene polymorphisms on mucosal cytokine expression, gastric inflammation, and host specific colonisation in Helicobacter pylori infection. The authors reported an association of the contrainflammatory interleukin 10 (IL-10) promoter haplotype (GCC) with higher mucosal mRNA levels and colonisation with more virulent cagA+, vacAs1+, and babA2+ strains in 207 patients with H pylori induced chronic gastritis. Rad et al identified pathogenicity genes of H pylori isolates by polymerase chain reaction based techniques from gastric biopsies.

However, the human stomach is colonised by more than one strain of H pylori, which obscures the investigation of germline mutations and host …