VIRAL-INFECTIONS, CYTOKINES AND ASTHMA AT TACKS IN CHILDREN

Respiratory viral infections, particularly rhinoviruses, are very impo rtant triggers of asthma exacerbation. The precise mechanisms of virus -induced exacerbations remain poorly understood, although human and an imal studies suggest that local production of cytokines (IL-6, IL-8, I L-11, Rantes, MIP1 alpha...) and the increased expression of intercell ular adhesion molecule 1 (ICAM1) in asthmatic individuals, play an imp ortant role in recruitment and activation of inflammatory cells in the airways. One hypothesis, that remains to be demonstrated, would be th at, in the presence of Th2 predominance, as occurs in asthma, an exces s of IL4 could inhibit the development of cytotoxic CD8, NK and Th1 ac tivity, thereby resulting in decreased IFN production, more severe all ergic inflammation and less efficient viral clearance.