TLR4 and respiratory syncytial virus bronchiolitis: Similarly, BAL fluid neutrophil mRNA expression for TLR4 was greater for preterm infants with RSV bronchiolitis (4.38 (0.122)) than for term infants with RSV bronchiolitis (2.46 (0.129), p = 0.037) and for controls (1.12 (0.577), p = 0.034).