Steroid-resistant Asthma Mechanism

Objective: To investigate the pathogenesis of and possibility of alternative therapy for steroid-resistant(SR) asthma.Methods: A total of 15 SR and 15 steroid-sensitive(SS) asthmatics were selected according to changes in FEV1 following a 7-day course of oral prednisone (20mg/d). (1) Numbers of glucocorticoid receptors (GR) in peripheral blood mononuclear cells (PBMCs) from SR and SS asthmatics were determined by radioligand-binding assay; (2) Serum levels of sIL-2R before and after oral prednisone therapy were measured using ELISA kit; (3) Influence of dexamethasone on the secretion of IL-4 by lymphocytes was evaluated by in vitro cell culture; (4) Inhibition of PHA-induced lymphocyte proliferation by dexamethasone, oxymatrine and tymus-derived immunosuppressor (TDIS) was investigated using lymphocyte proliferation assay.Results: (1) The average number of GR in PBMCs from SR asthmatics was significantly lower than that from SS asthmatics (P<0. 05), but there were 5 SR asthmatics whose GR numbers were in the normal range; (2) There was no difference in the baseline serum levels of sIL- 2R between SR and SS asthmatics, although they were significantly higher than that in normal controls. After oral prednisone therapy, levels of sIL-2R were significantly decreased in SS asthmatics (P<0. 001) but not in SR asthmatics(P>0.1),...