Chemokines, cytokines, and inflammatory cells in respiratory syncytial virus infection: Similarities to allergic responses

Aberrant immune responses at the time of respiratory syncytial virus (RSV) infection may explain many of the unique features of the illness caused by this virus. Immunologic hyperresponsiveness to viral antigens may explain the enhanced severity of illness in some individuals, the unfortunate experience with formalin-inactivated vaccines against RSV, and even the association of bronchiolitis with childhood asthma. In this review, we describe how RSV infection stimulates many of the same activation factors (NFκB, NF IL-6), chemokines (MIP-1α, eotaxin, RANTES), and inflammatory cells (eosinophils) that are involved in the pathogenesis of asthma. Important differences include the predominance of the Th1-like cytokine interferon gamma in RSV bronchiolitis. The potential importance of these findings in the pathogenesis of bronchiolitis and post-bronchiolitic wheezing is discussed.