Cord blood gene expression in infants hospitalized with respiratory syncytial virus bronchiolitis

Background. Only a few infants develop acute bronchiolitis when exposed to respiratory syncytial virus (RSV), and host, environmental, and viral properties are probably all of importance in determining the severity of infection. Methods. Microarray analysis was used to identify differentially expressed single genes and gene sets in cord blood from 5 infants hospitalized with RSV bronchiolitis versus cord blood from 5 control infants exposed to RSV without bronchiolitis during infancy. Quantitative real-time polymerase chain reaction (QRT-PCR) was performed on single genes in both the 5 infants selected for microarray analysis and 13 more infants hospitalized with the same disease. Gene set enrichment analysis (GSEA) was performed to identify differentially expressed gene sets within the microarray experiments. Results. Microarray analysis identified 15 single genes to be significantly differentially expressed between case and control infants. Eleven of these genes were evaluated with QRT-PCR, and the genes FAM102A, TNFRSF25, and STMN3 were down-regulated in all but 1 of the 18 infants. A pathway involved in regulation of the actin cytoskeleton was found to be clearly down-regulated when analyzed with GSEA. Conclusions. FAM102A, TNFRSF25, and STMN3 and a pathway involved in regulation of the actin cytoskeleton are down-regulated in cord blood from infants hospitalized with RSV bronchiolitis.