IL17A and sinusitis: To address this issue, we investigated whether cultured nasal polyp fibroblasts produce MIP-3α/CCL20 in response to IL-17A and tumor necrosis factor-α (TNF-α) (a proinflammatory cytokine) expressed in the sinus mucosa and nasal polyps in chronic sinusitis patients, and also examined 2 other IL-17 family members (IL-17E and IL-17F) for possible effects.