IL10 and bronchiolitis: Neutrophils predominate in bronchoalveolar lavage (BAL) from infants with hRSV bronchiolitis [14], [15], and respiratory secretions contain high levels of proinflammatory cytokines (e.g. tumour necrosis factor-α (TNFα), interleukin-6 (IL-6), IL-1α), CXC/CC chemokines (e.g. IL-8, MIP-1α, MCP-1 and RANTES) [16], and interferon (IFN)γ, IL-4, IL-5, IL-10, IL-9 and IL-17 [17], [18].