PTGIS and asthma: Pretreatment of ASMCs from patients with nonsevere asthma with dexamethasone inhibited this increase in expression in all mRNAs, apart from NAV2. In ASMCs from patients with severe asthma, dexamethasone caused a further increase in NAV2 and PTGIS expression (P < .01); in all other instances dexamethasone only slightly inhibited the FCS-induced mRNA expression to levels that were not comparable with ASMCs from patients with nonsevere asthma.