Sananez I, et al. - Given that IL-2 is critical for regulatory T cells (Tregs) growth, survival and activity, IL-2 production and function were analyzed in respiratory syncytial virus (RSV)-infected infants. In RSV-infected infants, CD4+ T cells produced lower amounts of IL-2 and displayed a reduced proliferative response compared with healthy infants. Findings suggested that disease severity was negatively correlated with both, the production of IL-2 by CD4+ T cells and the ability of exogenous IL-2 to restore the pool of FOXP3+CD4+ T cells.