Impaired tumor necrosis factor‐α secretion by CD4 T cells during respiratory syncytial virus bronchiolitis associated with recurrent wheeze

BACKGROUND: Infants with severe respiratory syncytial virus (RSV) bronchiolitis have an increased risk of recurrent wheezing and asthma. We aimed to evaluate the relationships between regulatory T cell (Treg) percentage and cytokine production of in vitro‐stimulated CD4+ T cells during acute bronchiolitis and the development of recurrent wheezing in the first 3 years of life. METHODS: We obtained peripheral blood from 166 infants hospitalized with their first episode of RSV‐confirmed bronchiolitis. Granzyme B (GZB) expression, and interleukin‐10, interferon‐γ, tumor necrosis factor‐α (TNF‐α), IL‐4, and IL‐5 production by in vitro anti‐CD3/CD28‐ and anti‐CD3/CD46‐activated CD4+ T cells, and percentage of peripheral Treg (CD4+CD25(hi)Foxp3(hi)) cells were measured by flow cytometry. Wheezing was assessed every 6 months. Recurrent wheezing was defined as three or more episodes following the initial RSV bronchiolitis. RESULTS: Sixty‐seven percent (n = 111) of children had wheezing after their initial RSV infection, with 30% having recurrent wheezing. The percentage of peripheral Treg (CD4+CD25(hi)Foxp3(hi)) cells was not significantly different between the wheezing groups. Decreased TNF‐α production from anti‐CD3/CD28− and anti‐CD3/CD46− activated CD4+ T cells was observed in the recurrent wheezers, compared with nonwheezers (p = .048 and .03, respectively). There were no significant differences in the GZB+ CD4+ T cells and production of other inflammatory cytokines between these groups. CONCLUSIONS: We demonstrated lower TNF‐α production by in vitro stimulated CD4+ T cells during severe RSV bronchiolitis in children that subsequently developed recurrent wheezing, compared with children with no subsequent wheeze. These findings support the role of CD4+ T cell immunity in the development of subsequent wheezing in these children.