IL33 and infection: Increased release of inflammatory cytokines was also observed at 18 hours post-infection with MSD analysis revealing raised levels of MIP-1a, MIP-2, MCP-1, TNF-α, IL-1β, IL-6 and IL-33 in BAL samples from CFTR-/- mice compared to controls (Fig 2A–J p ≤ 0.05).