Downward shift in serum IgM with Helicobacter pylori seropositivity

OBJECTIVE: To determine whether Helicobacter pylori infection is associated with premature immune ageing, with respect to circulating immunoglobulins. METHODS: Serum immunoglobulin classes and H. pylori anti-urease antibody were measured in 205 subjects (aged 30-89 years), obeying inclusion/exclusion criteria. RESULTS: IgM decreased (P<0.001) by 0.9 (95% C.I. 0.3, 1.4)% per year, H. pylori seropositivity having an effect equivalent to 25 years of ageing (P<0.02). IgA increased by 0.5 (0.1, 0.8)% per year (P<0.007), IgG being unaffected by age. Seropositivity had no effect on IgA or IgG. CONCLUSIONS: Increasing age and H. pylori seropositivity are each associated with a downward shift in circulating IgM. If clinical extrapolation is justified, H. pylori eradication may be important in combating susceptibility to infection in old age.