[Time trends of Th1 and th2 cytokines in induced sputum of asthmatic subjects during acute upper respiratory viral infections].
OBJECTIVE
Many asthma exacerbations are caused by respiratory viral infections that induce the interplay between Th1 and Th2 immune responses. However, the time trends for Th1 and Th2 immune responses during these phenomena have not been well studied.


OBJECTIVE
To identify possible mechanisms underlying the link between respiratory viral infections and asthma exacerbations.


METHODS
We recruited 40 adults aged 21-58 years for 4 groups. A. Healthy, B. Healthy with viral infection, C. Mild to moderate asthma and D. Same as C, but with viral infection. Th1 and Th2 cytokines in induced sputum samples during the course of acute upper respiratory viral infections in otherwise healthy and asthmatic subjects were monitored. IL-4, IL-5 and IFN-gamma were assayed by ELISA. Viral infection symptoms and asthma severity scores were monitored. Time trends were analyzed using linear mixed models.


RESULTS
IL-4 and IL-5 levels in groups C and D were higher than in groups A and B. IFN-gamma levels and viral infection symptoms scores in group B spiked by day 2 and rapidly declined by day 7, while in group D, IFN-gamma and symptoms scores for viral infection and asthma peaked much later (days 3-5) and slowly declined. The ratios of IL-4 and IL-5 to IFN-gamma in group D were significantly higher than in group C.


CONCLUSIONS
Infection-induced asthma exacerbations may be due to impaired anti-viral Th1-immune responses. There appears to be a critical window of 3-5 days for therapeutic intervention.
Zhang
Ding
D
Department of Respiratory Disease, Huashan Hospital, Fudan University, Shanghai, China.
Xia
Jingwen
J
Chen
Xiaodong
X
D000208:Acute Disease; D000328:Adult; D001249:Asthma / Q000276:immunology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012141:Respiratory Tract Infections / Q000276:immunology* / Q000821:virology*; D013183:Sputum / Q000276:immunology*; D058408:Th1-Th2 Balance; D013997:Time Factors; D055815:Young Adult