Prostaglandin H synthase 2 expression in airway cells from patients with asthma and chronic obstructive pulmonary disease

Products of the prostaglandin H synthase (PGHS) metabolic pathway are thoug ht to play a role in the pathogenesis of asthma. We determined the level of expression of the constitutive (PGHS-1) and inducible (PGHS-2) isoforms of the enzyme in induced sputum and bronchial biopsies of patients with asthm a, patients with chronic obstructive pulmonary disease (COPD), and unaffect ed control subjects by immunocyto- and immunohistochemistry. Immunoreactivi ty for PGHS-2 was significantly greater in the induced sputum of patients w ith asthma and patients with COPD compared with unaffected control subjects . The level of PGHS-2 was greater in asthma than in COPD. Immunoreactivity for PGHS-1 increased in cells in the induced sputum of patients with asthma and patients with COPD compared with that of unaffected control subjects. Immunostained cells included macrophages, eosinophils, and neutrophils. Gre ater PGHS-2 immunoreactivity was seen in the submucosal inflammatory infilt rate and in the airway epithelium of patients with asthma compared with una ffected control subjects. In summary, we demonstrate an induction of PGHS-2 in asthma, suggesting increased formation of prostanoids, which may contri bute to the inflammatory process.