Persistence of Nontypeable Haemophilus influenzae in Adenoid Macrophages: A Putative Colonization Mechanism

Abstract
Forsgren J, Samuebon S, Borrelli S, Christensson B, Jonasson J, Lindberg AA. Persistence of nontypeable Haemophilus influenzae in adenoid macrophages: a putatitive colonization mechanism. Acta Otolaryngol (Stockh) 1996; 116: 766-773. That nontypeable H. influenzae (NTHI) can reside intracellular in human adenoid tissue has been suggested by use of in situ hybridization of a fluorescein labelled 16S rRNA-targeted oligonucleotide probe (FISH). Adenoid tissues from 43 children operated on in a clinically infection-free interval were investigated. FISH revealed H. influenzae in macrophage-like cells, located subepithelially in the crypts in all 43 adenoids. Furthermore, H. influenzae was detected in 22/22 adenoids using immunohistochemistry with the monoclonal antibody MAHI-3 recognizing a conserved H. influenzae LPS inner-core region. FISH- and staining with monoclonal antibodies against immunophenotypic markers were performed simultaneously in order to characterize the cellular interrelations in this microenvironment. the findings of widespread presence of H. influenzae in cells of which some strongly expressed the CD 14 marker of the monocyte/macrophage lineage may correspond to an important aspect of the colonization mechanisms whereby NTHI persists in the nasopharynx of children.