A study published in Science Translational Medicine suggests that a combination of factors, including a potential genetic susceptibility, may explain why some children are prone to recurrent tonsillitis caused by group A Streptococcus. The researchers wrote that this information may be useful in developing a vaccine against the bacteria.
“It has remained a longstanding mystery why some children get recurrent strep infection and others do not,” Shane Crotty, PhD, a professor in the division of vaccine discovery at La Jolla Institute for Immunology, told Infectious Diseases in Children. “Understanding the immunologic mechanisms may allow us to better define which children are at risk and potential vaccine targets to prevent disease.”
Crotty and colleagues wrote that recurrent tonsillitis places a significant burden on the health of children. The condition is associated with hundreds of thousands of school absences every year and more than 750,000 tonsillectomies in the United States.
The researchers conducted phenotypic, genotypic and functional studies on tonsils collected from children with recurrent and nonrecurrent tonsillitis caused by group A Streptococcus (GAS).
Children with recurrent tonsillitis had fewer germinal center T follicular helper cells in their tonsils compared with children without recurrent tonsillitis.
Source: J.M. Dan, et al. Science Translational Medicine (2018).
Upon examination, tonsils removed from children with recurrent tonsillitis had smaller germinal centers — the space in which B and T cells interact — and they had fewer GAS-specific CD4+ germinal center T follicular helper cells, which orchestrate the immune response to GAS infection, the researchers said.
Because children with recurrent tonsillitis were significantly more likely to have a family history of tonsillectomy, the researchers suggested that a genetic predisposition may exist for recurrent tonsillitis. In their analysis, Crotty and colleagues identified two variations in genes that were associated with recurrent tonsillitis.
In addition, children with recurrent tonsillitis had a reduced antibody response to streptococcal pyrogenic exotoxin A, which Crotty said was an important target for vaccine development.
“We identified a role for GAS virulence factor and its ability to disrupt the immune system,” he said. “We find this virulence factor converts a helper cell of the immune system into a killer cell that attacks the immune system and damages the ability to make antibodies against GAS. The bacteria short-circuits the immune system by having it kill immune system cells. A vaccine against this virulence factor may prove useful against recurrent tonsillitis and strep throat more generally.” – by Katherine Bortz
Disclosures: The authors report no relevant financial disclosures.