S100A9 and chronic rhinosinusitis: Interestingly, several antimicrobial proteins differentially expressed in nasal mucosa from patients with chronic rhinosinusitis (e.g. BPIFA1, BPIFB1, BPIFB2, LTF, LYZ, S100A8, S100A9)46 were upregulated in amniotic fluid with increasing gestational age.