Since Helicobacter pylori persist for decades in the human stomach, the aim of this study was to examine the long-term course in H. pylori-specific serum IgG responses with respect to subclass and antigenic target. We studied paired serum samples obtained in 1973 and in 1994 in Vammala, Finland from 64 healthy H. pylori-positive adults and from other healthy controls. H. pylori serum IgA, IgG, and IgG subclass responses were determined by antigen-specific ELISAs. H. pylori-specific IgG1 and IgG4 subtype responses from 47 subjects were similar in 1973 and 1994, but not when compared to unrelated persons. H. pylori-specific IgG1/IgG4 ratios amongst the participants varied > 1000-fold; however, 89.4% had an IgG1/IgG4 ratio >1.0, consistent with a predominant IgG1 (Th1) response. Furthermore, ratios in individual hosts were stable over the 21-year period (r=0.56, p< 0.001). The immune response to heat shock protein HspA was unchanged in 49 (77%) of the 64 subjects tested; of the 15 who changed serostatus, all seroconverted and were significantly younger than those who did not change status. These findings indicate that H. pylori-specific antibody responses are host-specific with IgG1/IgG4 ratios stable over 21 years, IgG1 responses predominating, and HspA seroconversion with aging.

No abstract