Furthermore, high serum levels of TNFα and IL-6 are observed in psoriasis patients compared with healthy controls [80], and IL-1α, which is primarily produced by skin keratinocytes, regulates proliferation and differentiation and dictates immune function [81], via priming IL-23-induced modulation of IL-17A production by T cells [82,83,84,85]. This evidence concerns the gene IL1A and psoriasis.