Time dependent change of inflammatory cells in the sputum of patients with asthma on acute exacerbation

Lee, June Hyuk; Han, Sang Hoon; Cha, Kun Young; Park, Sung Woo; Uh, Soo Taek; Kim, Yong Hoon; Park, Choon Sik

Abstract

BACKGROUND AND OBJECTIVES: Infiltration of eosinophils into the airway is a characteristic finding of chronic persistent asthma regardless of the subtype. However, neutrophils are increased in the bronchial tree of a certain group of patients with acute exacerbation. The findings from the crosssectional studies of chronic persistent asthma and exacerbated asthma suggest that the infiltration of eosinophils in stable asthma is replaced with neutrophils in exacerbation of asthma. There has been, however, no observation of whether the pattern of inflammatory cells in airway is similar between those at stable state and on exacerbation in the same patients. The aim of this study is to evaluate the relation of cellular patterns in airway of asthmatics between those at stable state and on exacerbation.
METHODS
Forty-two asthmatics with acute exacerbation were enrolled in this study. The exacerbation was defined when daily diurnal variation of PEFR was more than 30%, PEFR was reduced more than 20% compared with the individual's best value and asthma symptoms were aggravated. The pattern of cellular infiltration at the presentation of exacerbation was divided into three groups according to the proportion of eosinophils and neutrophils. Neutrophil and eosinophil patterns were defined when the percentage of neutrophils and eosinophils in sputum exceeded 70% and 25%, respectively. A mixed pattern was defined when the percentages of neutrophils and eosinophils were out of range of either neutrophil or eosinophil pattern. Ten patients with asthma had experienced 2 or more attacks of acute exacerbation.
RESULTS
Age, smoking, allergic skin test, and pulmonary function test showed no difference among the three groups. When compared at stable state and on exacerbation, the number of neutrophil-pattern and the eosinophil-pattern were increased from 8 and 9 patients to 18 and 13, respectively, while the number of mixed pattern was reduced from 25 to 11 patients. The agreement of cellular pattern between those at stable state and on exacerbation state was 27.8% (5/18) in the neutrophil pattern, 16.7% (3/18) in the eosinophil pattern and 55.6% (10/18) in the mixed group. The overall rate of agreement was 42.9% (18/42). When the cellular patterns of repeated exacerbation were compared, 70% (7/10) of patients showed the same patterns of two or more exacerbation states, and 60% (2/3) showed the same patterns of three or more exacerbation states.
CONCLUSION
The cellular compositions of sputum at stable state are not closely related with those of exacerbation state, but the pattern of airway inflammation tended to be similar between repeated attacks of exacerbation.