The Role of Kallikrein-Related Peptidases in Atopic Dermatitis.

Excessive protease activity is a characteristic abnormality that affects the epidermal barrier in patients with atopic dermatitis (AD). Kallikrein-related peptidases (KLKs) are excessively expressed in AD lesions, and it is suggested that the abnormal action of KLKs is involved in the skin barrier dysfunction in AD. In other words, overexpressed KLKs disrupt the normal barrier function, and due to that breakdown, external substances that can become antigens of AD easily invade the epidermis, resulting in dermatitis, coupled with the induction of Th2 cytokines. Further investigations are required to elucidate the role of KLKs in AD; this knowledge could contribute to the design of new therapeutic and prophylactic drugs for AD.