IgA levels and carrier rate of Haemophilus influenzae and beta-haemolytic streptococci in children undergoing tonsillectomy.

Studies of IgG, IgA, IgM and IgE in serum and of IgG, IgA and IgM in saliva were performed in 52 children undergoing tonsillectomy. The results revealed that levels of IgA in serum and saliva in the patients were significantly reduced as compared with levels in age- and sex-related healthy controls (p less than 0.001 and less than 0.025 respectively). Recovery of beta-haemolytic streptococci and Haemophilus influenzae from the removed tonsils was also well correlated with low IgA in serum (p less than 0.01). A considerable lack of IgA fluorescing plasma cells in tonsillar tissue demonstrated in an earlier study of the same patients was consistent with carriage of beta-haemolytic streptococci and Haemophilus influenzae (p less than 0.01). The significant decrease in serum- and saliva IgA was only found among the youngest patients in this study. The hypothesis is raised that the decreased level of saliva IgA influences the increased tendency at pathogenic bacteria to adhere to and colonize on the tonsil mucosa, and furthermore, the lack of IgA plasma cells in the tonsils supports the view that IgA prevents penetration of microorganisms through the epithelial surface, secondarily establishing an acute inflammation of the tonsils.