IL4 and asthma: Cytokines measured in the lung digest showed increased levels of Th2 cytokines (IL-4, 5, 13) (p = 0.0022), the Th17 cytokine IL-17 (p = 0.0022) and TNF-α (p = 0.0022), a pro-inflammatory cytokine implicated in airway pathology of asthma and potentially an important cytokine found in refractory asthma [25–27].