Analysis on respiratory syncytial virus infection in infants and young children and the relationship with interleukin-4

Objective To analyze respiratory syncytial virus infection in infants and young children during 2014 and explore the relationship of infection status with the level of interleukin-4 in serum samples. Methods Totally 150 children with ARI were recruited in this study, and collected throat swabs from them. RSV was identified and differentiated into subgroups A and B by real-time RT-PCR. The total of IL-4 concentration in serum samples was measured by ELISA. Results Out of the 150 samples, 32(21.33%)were positive for RSV. Subtyping for A and B showed that 25 cases were subgroup A and 7 cases were subgroup B. Comparing between RSV infection group and normal control group, the former had higher serum IL-4 level [(328.67±52.96)ng/L vs.(217.34±51.21)ng/L, P<0.01], additionally B subgroup presented higher concentration than A subgroup[(371.09±61.96)ng/L vs.(316.80±44.63)ng/L, P<0.05]. Analysis of clinical data indicated that infection of B subgroup probable caused more serious wheeze symptoms than that by subgroup A. Conclusions Infection of RSV subtype A was predominant in Oct. 2014 to Mar. 2015. Level of serum IL-4 was increased statistical significantly after RSV infection. Furthermore, infection of subtype B might cause more severe illness. Key words: Respiratory syncytial virus; Acute respiratory infection; Interleukin-4