The role of Haemophilus influenzae in the pathogenesis of tonsillar hypertrophy in children

Abstract

The role of specific bacteria in the pathogenesis of tonsillar hypertrophy in children in unknown. To determine the effect of specific bacteria on the presence and nature of tonsillar hypertrophy (measured both clinically and by tonsil weight), quantitative aerobic bacteriology was performed on 54 tonsil-core specimens from 54 children undergoing tonsillectomy for chronic tonsillitis and/or tonsillar hypertrophy. Twelve tonsil-core biopsies from 12 children with no history of tonsil disease served as controls. Haemophilus influenzae (HI), Streptococcus pyogenes (SP), Streptococcus pneumoniae (SPn), and Staphylococcus aureus (SA) were the most common microorganisms cultured from diseased tonsils. Few bacteria were cultured from the cores of controls. HI was cultured as the dominant aerobic bacteria in 15 of 54 tonsils (27%). For HI alone, the number of bacteria/gram tonsil showed a significant positive correlation to tonsil weight (p less than 0.05). Fourteen of 15 (94%) tonsils with HI were found in patients with clinical tonsillar hypertrophy, while only 6 of 10 patients (60%) with SP and SPn had tonsillar hypertrophy. Of the 38 tonsils removed for obstructive symptoms (clinical hypertrophy), 14 of 38 (37%) cultured HI as the dominant microorganisms, whereas only 6 of 38 (16%) cultured SP. Neither the type of HI (b vs. non-b) nor the presence of beta-lactamase production had a significant correlation to tonsil weight, bacterial load or the number of B- or T-cell subsets. The number of T-helper (Th), T-suppressor (Ts) and B-cells (per gram/tonsil) was markedly greater in all diseased tonsils than in controls. For both HI and SP the total number of bacteria/gram tonsil correlated positively to the number of Ts cells (p less than 0.003 and p less than 0.007, respectively). In patients with HI type b (HI-b), the tonsil weight correlated to an increase in Ts and B-cells (p less than 0.004 and p less than 0.007, respectively). An increased presence of the Ts and B-cells in the HI-b tonsils (and not in tonsils with HI non-b) suggests a differential response by the tonsil to these distinct but related bacteria. The above data strongly support an etiological role for HI in the pathogenesis of tonsillar hypertrophy in children. Alterations in the relationship between Th and Ts cells may affect normal B-cell function and be implicated in this phenomenon. Clinical implications for pathogenesis, antimicrobial therapy, and future directions for research are discussed.