Changes of glucocorticoid receptor expression in the nasal polyps of patients with chronic sinusitis following treatment with glucocorticoid

Glucocorticoids (GCs) bind to the cellular glucocorticoid receptors (GRs) to exert anti-inflammatory and immunosuppressive actions. We investigated the changes in the expressions of the two GR isoforms, GR-alpha and GR-beta, in nasal polyps treated with GC. Immunofluorescent staining revealed prominent expression of GR-alpha in the inflammatory cell infiltrate in the polyps obtained from patients with chronic sinusitis and bronchial asthma. Furthermore, while the expression of GR-alpha was significantly reduced following GC treatment, that of GR-beta remained unchanged. The results of real-time PCR also revealed that the prominent expression of GR-alpha mRNA in the polyps decreased following GC treatment, while the expression of GR-beta mRNA remained unchanged. The observations indicate that GR-alpha may play the major role in the inflammation associated with nasal polyps and the ratio of the expression level of GR-beta to that of GR-alpha may serve as a useful index of the clinical efficacy of GC treatment.