Bronchoalveolar lavage cytokine profiles in acute asthma and acute bronchiolitis.
BACKGROUND
The pathogenetic basis for the relationship between acute bronchiolitis and asthma has not yet been completely elucidated.


OBJECTIVE
The aim of this study was to compare these 2 diseases in terms of their patterns of airway cytokine response (T(H)1 or T(H)2).


METHODS
By using a bronchoalveolar lavage (BAL) technique, this study investigated the cytokine levels of BAL fluid in children with acute asthma who had no identifiable respiratory syncytial virus (RSV) infection (n = 18) and in infants with acute bronchiolitis caused by RSV (n = 22). Comparisons were made with normal control subjects (n = 14). IFN-gamma (T(H)1) and IL-4 and IL-5 (T(H)2) levels were measured in concentrated BAL fluids by means of ELISA.


RESULTS
The IL-5 level (P <.001) and IL-5/IFN-gamma ratio (P <.001) were significantly increased in the asthmatic group with no identifiable RSV infection and in the RSV-induced bronchiolitis group compared with values in the control group. When infants in the bronchiolitis group were divided into eosinophil-positive and eosinophil-negative subgroups, the eosinophil-positive subgroup had significantly increased IL-5 levels (P <.001) and IL-5/IFN-gamma ratios (P <.01) compared with those in the control group, but similar cytokine responses were not induced in the eosinophil-negative subgroup. The percentage of BAL eosinophils correlated significantly with levels of BAL IL-5 in both the asthma group (r = 0.80, P =.000) and the bronchiolitis group (r = 0.82, P =.000).


CONCLUSIONS
These findings suggest that a subgroup of the RSV-induced bronchiolitis group results in a T(H)2-type response, and this could provide a valuable framework to explain the link between RSV-induced bronchiolitis and asthma.
Kim
Chang Keun
CK
Department of Pediatrics, Inje University Sanggye Paik Hospital, Seoul, Korea.
Kim
Sang Woo
SW
Park
Choon Sik
CS
Kim
Beyong Il
BI
Kang
Hee
H
Koh
Young Yull
YY
D000208:Acute Disease; D001249:Asthma / Q000276:immunology*; D001988:Bronchiolitis / Q000276:immunology*; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology / Q000276:immunology*; D001999:Bronchoscopy / Q000009:adverse effects; D002648:Child; D002675:Child, Preschool; D016207:Cytokines / Q000032:analysis* / Q000235:genetics; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000032:analysis; D015847:Interleukin-4 / Q000032:analysis; D015848:Interleukin-5 / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D018357:Respiratory Syncytial Virus Infections / Q000276:immunology; D018418:Th2 Cells / Q000276:immunology
D016207:Cytokines; D015848:Interleukin-5; D012333:RNA, Messenger; D015847:Interleukin-4; D007371:Interferon-gamma