Lichen Planopilaris Is Characterized By Immune Privilege Collapse Of The Hair Follicle's Epithelial Stem Cell Niche

The study on lichen planopilaris (LPP) involved 42 adult patients and demonstrated that the disease was characterized by the collapse of immune privilege in the hair follicle's epithelial stem cell niche, specifically in the bulge area. This collapse was marked by increased expression of MHC class I and II molecules and a reduction in TGFβ2 and CD200 expression, leading to a Th1-biased cytotoxic T cell response. The findings suggested that interferon-γ (IFNγ) played a significant role in this process, indicating that LPP might be an autoimmune disease. The study proposed that protecting or restoring immune privilege in the bulge could be a therapeutic strategy for managing this form of cicatricial alopecia.