Abstract:Objective To investigate the changes of serum IL-4, IL-8 and lymphocyte subsets in infants with acute bronchiolitis caused by respiratory syncytial virus. Methods Totally 142 children with acute bronchiolitis caused by respiratory syncytial virus were recruited from March 2014 to June 2018 in Nanxishan Hospital of Guangxi Zhuang Autonomous region. They were divided into mild, moderate and severe groups according to the severity. Each group was subdivided into ≤6 months subgroup and > 6 months subgroup. A control group was set, which contained Healthy infants (11 cases) and in-hospital preparation infants (26 cases) excluding infection. Serum level of IL-4 and IL-8 and proportion of lymphocyte subsets were measured in each group. Results The levels of IL-4 and IL-8 were the highest in the severe group, and the difference was statistically significant compared with other groups (P?0.05). The ratio of CD3+ CD4+ T lymphocyte in severe group was higher than that in other groups, and the ratio of CD3+ CD8+ and CD3+ CD56+ T lymphocyte in severe group was lower than that in other groups, and the ratio of CD3+ CD4+ T lymphocyte in severe group was the lowest (P?0.05). Conclusions Patients in different age and disease severity with bronchiolitis caused by respiratory syncytial virus have influence on serum IL-4, IL-8 levels and lymphocyte subsets.