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. (C) 2000 The British Infection Society.