OBJECTIVETo investigate the therapeutic mechanism of three-step sequential method (TSSM) on patients with corticosteroid-dependent asthma (SDA).

METHODSForty patients with SDA were randomly assigned according to the randomizing number table to two groups equally, the treated group treated with three-step sequential recipes plus inhalation of Pulmicort Turbuhaler 200 microg, twice a day, and the control group treated with Pulmicort Turbuhaler alone. The therapeutic course for both groups was 12 - 14 weeks. Changes of the symptom score of asthma, the corticosteroid dosage used and the lung function were observed and the positive expression rate of IFN-gamma and IL-4 in peripheral CD4+ T cells were determined by flow cytometry before and after treatment.

RESULTSThere was significant difference in the asthma symptom score, the oral corticosteroid dosage and the lung function between the treated group and the control group after treatment (P < 0.01). The expression rate of Th2 reduced, the ratio of Th1/Th2 increased significantly after treatment in both groups (P < 0.01, P < 0.05), but the changes were more remarkable in the treated group than those in the control group, showing significant difference between them (P < 0.01), while the expression rate of Th1 had no obvious change after treatment with no significant difference shown between the two groups (P > 0.05).

CONCLUSIONTSSM can regulate imbalance of Th1/Th2, inhibit generation of inflammatory cytokines, decrease airway hyper-response, and therefore improve the pulmonary function, alleviate the asthmatic symptoms and reduce the patients' dependence on corticosteroid.