To determine if the increased expression of TLR4 mRNA in the blood compared with the BAL fluid was also observed for the other TLRs, the mean mRNA expression of TLRs 2, 7, 8 and 9 in blood neutrophils for the two groups with RSV bronchiolitis and the control group was measured (fig 4C). This evidence concerns the gene TLR4 and respiratory syncytial virus bronchiolitis.