Human kallikrein-related peptidases (KLKs) have been emerging as important factors in pathophysiology of skin inflammatory diseases. Among trypsin-like KLKs, KLK8 is abundantly found in the stratum corneum and in sweat. KLK8 expression is increased in inflammatory skin diseases and skin tumors. However, its function in normal and disease skin remains relatively unexplored. Several previous experiments using human samples and Klk8 knockout (Klk8-/-) mice have shown that KLK8 might be associated with skin barrier integrity and inflammation in response to external stimuli and/or wounding.