S100A8 and psoriasis: MKP-1−/− mice are hypersusceptible to IMQ-induced psoriasiform skin disease, which was associated with an increased expression of Il1b, Cxcl2, and S100a8. Chimeric experiments showed that MKP-1 acted on both hematopoietic and non-hematopoietic cells to regulate psoriasis pathogenesis.