Lympho-epithelial Kazal-type-related inhibitor (LEKTI) also known as serine protease inhibitor Kazal-type 5 (SPINK5) is a protein that in humans is encoded by the SPINK5 gene.

This gene encodes a multidomain serine protease inhibitor that contains 15 potential inhibitory domains. The inhibitor may play a role in skin and hair morphogenesis and anti-inflammatory and/or antimicrobial protection of mucous epithelia. Mutations may result in Netherton syndrome, a disorder characterized by ichthyosis, defective cornification, and atopy. Multiple transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008].
Function: Serine protease inhibitor, probably important for the anti-inflammatory and/or antimicrobial protection of mucous epithelia. Contribute to the integrity and protective barrier function of the skin by regulating the activity of defense-activating and desquamation-involved proteases. Inhibits KLK5, it's major target, in a pH-dependent manner. Inhibits KLK7, KLK14 CASP14, and trypsin.