Helicobacter pylori in the palatine tonsils of patients with IgA nephropathy compared with those of patients with recurrent pharyngotonsillitis.

Helicobacter pylori infection is acquired by oral ingestion. However, the morphology and microscopic localization of H pylori in the human oral cavity and pharynx are unknown. In the present study, we performed immunohistochemistry, immunoelectron microscopy, in situ hybridization, and polymerase chain reaction to identify H pylori in the palatine tonsils of 32 patients with immunoglobulin A nephropathy (IgAN) and 141 patients with recurrent pharyngotonsillitis (RPT). H pylori in coccoid form was present in bacterial colonies and horny layers of the stratified squamous epithelium in tonsillar crypts. We described for the first time the morphology of H pylori in palatine tonsils. Most bacterial colonies were sulfur granules with Actinomyces israelii (A israelii), and A israelii showed significant coexistence with H pylori (P=.011). The prevalence of H pylori in palatine tonsils of the RPT group increased steeply with age, but one fourth of the patients were found not to have tonsillar H pylori in adulthood. All patients with IgAN had H pylori in palatine tonsils. The prevalence of H pylori was greater in the IgAN group than in the RPT group, and the difference was statistically significant (P<.001). In contrast, A israelii was unrelated to age and clinical diagnosis (P=.722). In conclusion, our results demonstrate that H pylori in coccoid form is present in palatine tonsils and may indicate that H pylori in palatine tonsils is among the antigens causative of IgAN.