Elevated transglutaminase‐2 expression in the epidermis of psoriatic skin and its role in the skin lesion development

Psoriasis, an inflammatory skin disease triggered by the immune system, presents keratinocyte hyperproliferation, differentiation and angiogenesis. The role of transglutaminase‐2 ( TG 2) in psoriasis has not been fully established yet. In this retrospective, non‐randomized and non‐blinded study, skin biopsies were collected from 37 psoriatic patients and immunohistochemical staining was performed. TG 2 staining was positive in all 37 samples, among which 32 were strong and five weak. The localization of TG 2 staining was present in the epidermis and spreading from basal layer to stratum granulosum in decreasing staining intensity. However, TG 2 was also expressed in the basal layer in the non‐lesional site of psoriasis and the skin of healthy people. The presence of TG 2 was not associated with disease duration, stage of disease and subtype of psoriasis. Overexpression of TG 2 seems to be an important role in psoriatic development.