Normal human sweat contains interleukin-8.

Sweating in humans is induced by physical or emotional stress, which raises the possibility that sweating may relate to host defense. We therefore asked whether human eccrine sweat attracts leukocytes and found that it is chemotactic for human neutrophils. This activity was due to several chemoattractants, one of which was interleukin-8 (IL-8). Using immunohistochemistry and in situ hybridization IL-8 and its mRNA have been detected in sweat gland epithelium, indicating that IL-8 is produced in situ. This establishes a pattern of physiological IL-8 secretion by exocrine glands and suggests that, in addition to its role as a major inflammatory mediator, IL-8 also has physiological homeostatic functions.