Effects of suplatast tosilate on allergic eosinophilic airway inflammation in patients with mild asthma

Abstract

Background: Bronchial asthma is a chronic inflammatory disease characterized mainly by infiltration of the airway mucosa by various inflammatory cells, notably eosinophils. TH2-type cytokines are suggested to be deeply involved in the pathogenesis of asthma. Objective: We sought to determine the suppressive effects of suplatast tosilate, an inhibitor of TH2-type cytokines, on eosinophilic inflammation of the bronchial mucosa in patients with mild asthma. Methods: Airway hyperresponsiveness tests, pulmonary function tests, eosinophil measurements in induced sputum, and bronchial mucosa biopsies were performed before and after treatment with suplatast tosilate for 6 weeks in 15 patients with mild asthma and in 13 control patients with mild asthma not receiving suplatast tosilate. This study was performed as a case-controlled open study. Results: In the treatment group a significant improvement in the provocation concentration of histamine was observed (P < .05). Improvements in peak expiratory flow (P < .01) and in symptom score (P < .05) were also noted in the suplatast tosilate–treated group. Moreover, the average number of infiltrating eosinophils and EG2+ cells significantly decreased (both P < .05), as did the ratios of eosinophils and EG2+ cells in sputum (both P < .01). The average number of CD4+ and CD25+ T lymphocytes also decreased (both P < .05). Conclusion: Suplatast tosilate appears to inhibit allergic airway inflammation mediated by TH2-type cytokine and to improve clinical symptoms in patients with mild asthma.