NOS2 and primary ciliary dyskinesia: We were particularly interested in the possibility that Hb could be expressed in ciliated epithelium because it could modify chemistry downstream of NOS activity, as it does in the vasculature, nitrogen oxide signaling has been difficult to understand in a number of airways diseases including asthma6, cystic fibrosis (CF)3, sickle cell anemia7, and primary ciliary dyskinesia (PCD)8.