An antimicrobial protein, lactoferrin exists in the sweat: proteomic analysis of sweat.

The main function of the eccrine gland has been considered to be thermoregulation. Recently, it has been reported that antimicrobial peptides including cathelicidin and dermcidin exist in the sweat. Lactoferrin is found in body fluids such as milk tears and saliva. It is known as a component of host defense against infection and inflammation. In this study, we explored whether lactoferrin is produced by eccrine glands, thereby establishing its potential role in the skin defense. By immunohistochemistry, lactoferrin was detected in eccrine glands of normal human skin. In Western blot analysis, lactoferrin was found in sweat and skin surface substances obtained from healthy volunteers. By proteomic analysis, lactoferrin and other antimicrobial peptides were detected in sweat. In addition, we measured the concentration of lactoferrin in sweat by enzyme-linked immunosorbent assay. These findings suggest that lactoferrin may contribute to skin defense against infection through its secretion in sweat.