Haemophilus influenzae and Streptococcus pyogenes Group A Challenge Induce a Th1 Type of Cytokine Response in Cells Obtained from Tonsillar Hypertrophy and Recurrent Tonsillitis

Abstract

We have previously shown that tonsil tissue both from children with tonsillar hypertrophy and recurrent tonsillitis is colonized and invaded by Haemophilus influenzae and Streptococcus pyogenes group A. In order to evaluate if these bacteria are involved in the immunopathogenesis of these two conditions, tonsillar cells from both groups were stimulated in vitro with intact, heat-inactivated H. influenzae or S. pyogenes A. The immunoreactivity was evaluated by assessing the induction of cytokine production (IL-1α, IL-1β, TNF-α, IL-6, IL-8, IL-2, IFN-γ, IL-4, TNF-β and IL-10), which was detected at the single-cell level. All cytokines studied except IL-4 were induced in both groups after stimulation with H. influenzae or S. pyogenes A. The dominating cytokines were IL-1β, IFN-γ and TNF-β. No major differences in the cytokine pattern or number of cytokine-producing cells were noticed between the two patient cohorts after H. influenzae stimulation. Activation by S. pyogenes A bacteria gave rise to higher frequencies of IFN-γ- and TNF-β-synthesizing cells in the recurrent tonsillitis group. The incidence of CD4-, CD8-positive T cells and CD40-positive B cells was comparable between the two groups while the MAC-387-positive macrophages were significantly higher in the recurrent tonsillitis groups. In conclusion, a Th₁ type of cytokine response was found in both groups following stimulation with H. influenzae or S. pyogenes A.