Antibodies against Helicobacter pylori in feces and saliva before and after eradication therapy

Abstract

OBJECTIVE: To determine specific antibody levels against Helicobacter pylori antigens in stool and saliva specimens from H. pylori-infected subjects and seronegative controls. METHODS: Antibody levels against a total membrane preparation (MP) and purified flagellin from H. pylori were measured by enzyme-linked immunosorbent assays (ELISAs) in fecal extracts (FEs) and sera from 21 H. pylori-infected and 17 non-infected adult Swedish volunteers; specific antibody levels in saliva (IgG and IgA titers) were also measured in the majority of them. Follow-up specimens after successful eradication of H. pylori were collected after 5--7 weeks (all specimens) and 5 months (FEs and sera). RESULTS: Geometric mean specific IgA antibody levels, adjusted to total IgA concentration, in FEs were significantly higher (p<0.05) in the H. pylori-infected than in the control group against MPs (p<0.05) and flagelin (p<0.05). The total IgA concentrations in FEs from infected and seronegative controls were comparable and the IgA was mainly of the secretory type. Saliva specimens from H. pylori-infected subjects had higher ELISA IgA than IgG titers against MP. Anti-MP antibodies of both isotypes were higher in the infected than in the non-infected group (p<0.05 for both isotypes). The total IgA levels were also significantly (p<0.05) higher in saliva from the H. pylori-infected subjects than in saliva from the controls (geometric mean 292 mg/L and 173 mg/L, respectively). Eradication therapy resulted in a more rapid decline in antibody levels in FEs than in corresponding sera or saliva specimens. CONCLUSIONS: Specific antibodies against H. pylori MP were detected in FEs as well as in saliva from most of the infected volunteers, the mean antibody levels being significantly higher in specimens from the H. pylori-infected subjects than from seronegative controls. The results suggest that analyses of antibody levels in FEs may be used for follow-up of patients early (5--7 weeks) after onset of successful eradication therapy.