Korean J Asthma Allergy Clin Immunol.  2008 Mar;28(1):20-25.

Clinical Characteristics of Bronchial Asthmatics Who Showed Negative Conversion of Airway Hyperreactivity in the Methacholine Provocation Test

Abstract

BACKGROUND: Clinical characteristics of asthmatics undergoing negative conversion of bronchial hyperreactivity in the methacholine bronchial provocation test (M-test) were not completely evaluated yet. We investigated clinical characteristics of negative conversion of bronchial hyperreactivity in asthmatics. METHOD: We enrolled 57 patients who were treated more than 1 year at our clinic. We compared parameters of clinical data and the PC20 results of the pulmonary function test and M-test between the negative conversion group (NCG) of bronchial hyperreactivity and the control group with persistent bronchial hyperreactivity (CG). RESULT: Thirty of the 57 asthmatics showed negative conversion of bronchial hyperreactivity in the M-tests and included in NCG. The remaining 27 patients were included in the CG. There were no significant differences in sex, age, smoking history, atopic sensitization and the initial severity of asthma between the NCG and CG. The initial PC20 of the CG (1.31+/-2.03 mg/mL) was not significantly different from that of NCG (2.34+/-4.36 mg/mL) either. The mean treatment duration until negative conversion of bronchial hyperreactivity was 5.46+/-4.28 years. The initial TEC of the NCG (399.29+/-250.66 /mcL) was lower than that of the CG (608.92+/-371.74 /mcL)(P=0.018). Eosinophils in induced sputum (%) of the NCG (22.23+/-21.63%) was also lower than that of the CG (40.85+/-32.07%)(P=0.021). The initial FEV1 was higher in the NCG (86.06+/-15.96%) than in the CG (72.37+/-18.40%)(p=0.004). FEV1/FVC was also higher in the NCG (76.54+/-9.59%) than in the CG (65.43+/-11.14)(P<0.001). QOL scores were not significantly different between both groups.
CONCLUSION
The negative conversion group of bronchial hyperreactivity may show better pulmonary functions and milder eosinophilic inflammation.

MeSH Terms

Asthma
Bronchial Hyperreactivity
Bronchial Provocation Tests
Eosinophils
Humans
Inflammation
Methacholine Chloride
Respiratory Function Tests
Smoke
Smoking
Sputum
Methacholine Chloride
Smoke