Alopecia Areata: A Review of Disease Pathogenesis

F. Rajabi; L.A. Drake; M.M. Senna; N. Rezaei


The British Journal of Dermatology. 2018;179(5):1033-1048. 

In This Article

What Is Immune Privilege?

Some of the vital organs in the body have limited regenerative ability, and the slightest inflammation within them may have devastating outcomes. A revolutionary adaptation called IP protects such organs from the potential harm of immune recognition by creating an anergic state that could even tolerate a foreign graft within the tissue. The central nervous system, testes, placenta and eyes are among the well-known IP sites.

It has been proposed that HFs are also immune privileged sites (precisely, the bulge throughout the hair cycle and the bulb in the anagen phase). Evidence for this notion comes from two studies demonstrating the ability of melanocytes of a black guinea pig to survive in HFs grafted into albino guinea pig recipients, and the survival of human dermal sheath tissues within a sex-mismatch transplantation.[21–23]