TLR4 and respiratory syncytial virus bronchiolitis: In the BAL fluid, total neutrophil TLR4 was significantly less in term infants with RSV bronchiolitis than in preterm infants with RSV bronchiolitis (0.70 (0.02) vs 0.92 (0.02), p = 0.03), and both were less than in control infants (1.70 (0.028), p = 0.001; fig 3A, C).