DEFB4A and psoriasis: IL-17 responsive transcripts that are upregulated in psoriasis were analyzed in keratinocytes and included NFKBIZ, DEFB4, IL36G, and CCL20. To evaluate the contribution of the polarizing Th17 cytokines present in the Th17-derived supernatants keratinocyte cultures were incubated with CD3/CD28-specific antibodies together with IL-6, IL-1β, TGF-β, and IL-23 at the same concentrations used in the Th17 polarization assays.