Hair follicles

Abstract

The hair follicle (HF) is a skin appendage providing physical barrier to protect mammals from external stimuli. HF has been attracting great interest as an object of developmental and stem cell research, however, little attention has been paid to HF in the light of immunology. Previous observations supported that HF might enjoy immune privilege by suppressing immune-related antigen expression and producing immunosuppressive molecules, indicating HF possesses intrinsic machinery to escape from unwanted immune response. The recent discovery that HF segments differentially express chemokines, both chemoattractive and possibly suppressive, suggested that HF is not merely an innocent bystander but may play previously unrecognized roles in the regulation of immune reactions in skin. In this chapter, basic knowledge of hair follicle morphology and physiology is summarized. The similarities and differences between mouse pelage and human scalp hair follicles is presented, which is crucial for translational research. Finally, immunological features of hair follicle segments is discussed.