Type 1-like immune response is found in children with respiratory syncytial virus infection regardless of clinical severity

The immunological response of infants younger than six months to infection with respiratory syncytial virus (RSV) was studied in relation to clinical severity. IL-6 and IL-8 were found more frequently and at higher levels in the plasma samples of more severely ill patients and no significant differe nces were found in the levels of cytokines differentiating between Type 1 a nd Type 2 responses. Cellular infiltrates in nasopharyngeal washings consis ted mainly of polymorphonuclear granulocytes and monocytes. Eosinophils, ig E positive cells and tryptase positive cells were found sporadically. Analy ses of RSV stimulated T cell cultures established from peripheral blood mon onuclear cells, for intracellular and secreted cytokines showed that, irres pective of clinical severity, the responses were dominated by the productio n of IFN-gamma, and that only low levels of IL-4 and IL-10 were detectable. Collectively these data do not indicate an association between clinical se verity and a Type a-like T cell response. (C) 2000 Wiley-Liss, Inc.