In response to the TLR4 ligand LPS, PBMCs from PCD patients secreted significant higher levels of TNF-α (p < 0.01) (Fig. 6a), IL-1β (p < 0.05) (Fig. 6b), CCL3 (p < 0.001) (Fig. 7a) and CCL18 (p < 0.0001) (Fig. 7c). This evidence concerns the gene TLR4 and primary ciliary dyskinesia.