Calpain-1, highly expressed in psoriasis, promotes restricted proteolysis of IL-1α to produce a 17 kDa protein.[28, 29] In our study, mature IL-1α production induced by hS100A7 can be blocked by calpain-1 inhibitor PD151746 in NHEKs (Fig 3A). Here, IL1A is linked to psoriasis.