EFFECTS OF INTERLEUKINS, COLONY-STIMULATING FACTOR AND TUMOR-NECROSIS-FACTOR ON HUMAN HAIR FOLLICLE GROWTH IN-VITRO - A POSSIBLE ROLE FOR INTERLEUKIN-1 AND TUMOR-NECROSIS-FACTOR-ALPHA IN ALOPECIA-AREATA

The immune system may be involved in the regulation of normal hair fol licle growth as well as in the pathogenesis of some hair diseases. Imm unomodulatory cytokines not only act as mediators of immunity and infl ammation but also regulate cell proliferation and differentiation and, as such, may play an important part. in regulating hair growth. We ha ve investigated the effects of a number of interleukins (IL), colony s timulating factors and tumour necrosis factors (TNF) on hair follicle growth in vitro. Dose-response studies showed that IL-1 alpha, IL-1 be ta and TNF-alpha were potent inhibitors of hair follicle growth. The h istology of hair follicles maintained with inhibitory doses of IL-1 al pha, IL-1 beta and TNF-alpha showed similar changes in hair follicle m orphology, resulting in the formation of dystrophic anagen hair follic les. These changes in histology were characterized by the condensation and distortion of the dermal papilla, marked vacuolation of the hair follicle matrix, abnormal keratinization of the follicle bulb and inne r root sheath, disruption of follicular melanocytes and the presence o f melanin granules within the dermal papilla. Moreover, these changes in hair follicle morphology are similar to those reported in alopecia areata and suggest that IL-1 alpha, IL-1 beta and TNF-alpha may play a n important part in the pathophysiology of inflammatory hair disease.