For example, in CF patients, TLR2, TLR4, TLR5, and TLR9 expression was increased on airway PMNs compared with circulating PMNs, and TLR5 activation enhanced the respiratory burst activity of PMNs [34], and the ROS output from PMNs of CF did not differ from that of controls [7]. The gene discussed is TLR9; the disease is cystic fibrosis.