The role of adenoids in nasopharyngeal colonization with nontypeable Haemophilus influenzae.

Nasopharyngeal colonization with nontypeable Haemophilus influenzae (NTHi) and immune responses in the adenoid were studied in 18 patients with otitis media with effusion (OME) who underwent adenoidectomy. NTHi in excised adenoid tissue and in nasopharyngeal secretions was examined by quantitative culture assay. NTHi was detected in 13 adenoid samples and 12 nasopharyngeal secretions. In 11 cases, NTHi was cultured from both samples of nasopharyngeal secretion and adenoids, and the concentration of NTRi in nasopharyngeal secretions was significantly correlated with that in adenoids. A significant negative correlation was observed between anti-NTHi IgA antibody titers and the number of NTHi in nasopharyngeal secretions. The number of NTRi in nasopharyngeal secretions and adenoids was decreased in the cases having a large number of NTHi-specific IgA and IgG antibody-producing cells in their adenoids. The results suggest that mucosal immunity in the nasopharynx is responsible for reducing the colonization of NTHi, and that the adenoid plays an important role in regulating the immune responses.