Evidence that the bulge region is a site of relative immune privilege in human hair follicles

Abstract

Background: Recent gene profiling data suggest that, besides the anagen hair bulb, the epithelial stem cell region in the outer root sheath of hair follicles (HFs), termed the bulge, may also represent an area of relative immune privilege (IP). Objectives: To investigate whether the human HF bulge is a site of relative IP within anagen VI HFs. Methods: Anagen VI HFs from normal human scalp skin were analysed using immunohistological staining techniques, quantitative histomorphometry and statistical analysis. For functional evidence we performed full-thickness human scalp skin organ cultures to investigate whether interferon (IFN)-γ, a key inducer of IP collapse in hair bulbs, has a similar e..