[Eosinophil count in induced sputum samples as a marker of airway inflammation and adequacy of corticosteroid inhalation treatment in asthmatic patients].
We tried to use eosinophil counts in induced sputum samples as a marker of airway inflammation, and as a guide for reducing inhaled corticosteroids in patients with well-controlled persistent asthma. The eosinophil count in induced sputum smears was defined as follows: Eos%; eosinophil percentage of 200-400 leukocytes in properly cell-separated fields, TEC; total eosinophil counts in the 5 most eosinophil-dense high power view fields (x 400). First, the eosinophil count in induced sputum samples was compared between 29 asthmatic subjects treated with inhaled corticosteroid and 15 age- and sex-matched healthy controls. Second, inhaled corticosteroid was reduced by 50% in 20 patients with green-zone asthma (morning PEF > 80% of patient's best PEF). PEF measurements were followed prospectively for 12 weeks thereafter. Once PEF decreased below 70% of their best PEF, subjects were considered as treatment "failures". Both Eos% and TEC were significantly higher than in the controls, even in well-controlled (morning PEF > 80% of their best) asthmatic patients (p = 0.001, 0.03). The chance of treatment "failure" was significantly higher in those having more eosinophils (Eos% > 10%, TEC > 100) in their initial induced sputum sample (p = 0.03, 0.001). Airway inflammation still persists in many well-controlled chronic asthmatic patients, and induced sputum eosinophilia predicts an early decrease of PEF after reduction of inhaled corticosteroids.
Tomii
K
K
Department of Respiratory Medicine, Tenri Hospital, Nara, Japan.
Matsumura
Y
Y
Taguchi
Y
Y
Oida
K
K
Kobash
Y
Y
D000280:Administration, Inhalation; D000328:Adult; D000368:Aged; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage*; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage*; D001249:Asthma / Q000175:diagnosis / Q000188:drug therapy*; D001507:Beclomethasone / Q000008:administration & dosage*; D015415:Biomarkers; D001991:Bronchitis / Q000175:diagnosis*; D004804:Eosinophils; D005260:Female; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D010366:Peak Expiratory Flow Rate; D013183:Sputum / Q000166:cytology*
D018927:Anti-Asthmatic Agents; D000893:Anti-Inflammatory Agents; D015415:Biomarkers; D001507:Beclomethasone