Downregulation of IL7R, CCR7, and TLR4 in the cord blood of children with respiratory syncytial virus disease.

The association between gene expression at birth of 11 candidate genes with important innate and adaptive immune functions and later respiratory syncytial virus (RSV) disease was investigated. Cord blood was collected from 2108 newborns. Forty-seven were subsequently RSV positive. Gene expression analysis by quantitative reverse transcription-polymerase chain reaction was compared to 17 controls. There was downregulation of interleukin 7 receptor (IL7R) (P = .0001) and chemokine receptor 7 (CCR7) (P = .002), and in the severe disease subcategory, downregulation of Toll-like receptor 4 (TLR4) (P = .003). IL7R and CCR7 facilitate communication between adaptive and innate immune systems. TLR4 activates the innate immune system on RSV exposure. Delayed innate and adaptive immune activation may predispose children to more severe RSV disease.