Abstract
BACKGROUND: Some bacterial and viral infections may reduce the risk of atopy, and this is based on the concept of their ability to divert the immune system towards the Th1 responses. Most of the hepatitis B virus (HBV) infections occur in the developing countries and this is where atopic disorders are least prevalent. Th1 responses are important for the viral clearance of HBV and also for antibody production. The aim of the study is to investigate whether the presence of antibodies to the hepatitis B surface antigen (anti-HBs) is inversely associated with atopy in adults. METHODS: A random sample of 358 subjects, who were without hepatitis B surface antigen, was recruited; they were aged from 18 to 79 years (105 young adults aged <40 years and 253 older adults aged > 40 years). Determinations of the anti-HBs and skin prick tests using aeroallergens were performed. Those subjects with one or more positive skin reactions (a mean wheal diameter 23 mm) were considered atopic. RESULTS: The prevalence rate of atopy (p=0.035) or the sensitization to Dermatophagoides farinae (p=0.01) was significantly lower in the subjects with anti-HBs than in those subjects without anti-HBs for the young adults, but not for the older adults. The logistic regression analysis that was done on the young adults showed that the presence of anti-HBs was associated with a significantly lower risk of atopy (the odds ratio adjusted for confounding variables = 0.40 [95% CI 0.16-0.981, p=0.046) or with the sensitization to D. farinae (0.20 [0.06-0.65], p = 0.008). CONCLUSION: The presence of anti-HBs produced by a natural HBV infection or vaccination might be inversely associated with atopy in young adults.