Recurrent tonsillitis disease (RT) is a common indication for pediatric tonsillectomy, the most frequent childhood surgery. It is unknown why some children develop RT. The present disclosure demonstrates that RT tonsils exhibit significantly smaller germinal centers than non-RT tonsils, concomitant with a bias against Group A Streptococcus (GAS)-specific germinal center follicular helper CD4+ T cells (GC Tfh), and significantly reduced antibodies to the GAS virulence factor SpeA. The present disclosure also shows a significant immunogenetic component to this disease, with the identification of ‘；at risk’； and ‘；protective’； HLA alleles for RT. Finally, the present disclosure identifies a new cell type, granzyme B+GC Tfh cells, which are activated by SpeA, are significantly more abundant in RT GC Tfh cells, and have the capacity to kill B cells, thus, providing a window into the immunology and genetics of a classic childhood disease and identifies a new type of pathogenic T cell.
