Hair follicle immune privilege in autoimmune and immune-mediated alopecias: paths toward reestablishing immune tolerance - PubMed
4 hours ago
- #alopecia
- #hair follicle
- #immune privilege
- Autoimmune and immune-mediated alopecias result from site-specific failures of hair follicle immune privilege, leading to reversible or irreversible hair loss.
- Alopecia areata (AA) involves cytotoxic injury at the anagen bulb but spares stem cells, allowing regrowth after immune suppression.
- Lichen planopilaris (LPP) and frontal fibrosing alopecia (FFA) feature chronic interface dermatitis that destroys the stem cell niche, causing permanent fibrosis.
- Discoid lupus erythematosus (DLE) of the scalp is driven by immune-complex-mediated complement injury to the upper follicle.
- Central centrifugal cicatricial alopecia (CCCA) is a fibroblast-dominant process linked to chronic stress and stromal remodeling.
- These conditions are categorized into four follicular immune network archetypes based on immune privilege collapse, effector programs, and stromal changes.
- A NEST framework organizes these archetypes into a taxonomy of intrinsic follicular privilege, local tolerogenic repertoires, and stromal checkpoint circuits.
- AA targets the anagen bulb, DLE affects the upper follicle and interfollicular epidermis, LPP/FFA focuses on the bulge stem cell niche, and CCCA converges on the upper follicle-interfollicular epidermis unit.
- AA and DLE show resolved clonotypic effector modules with pathogenic T or B cells, while LPP/FFA and CCCA involve polyclonal networks with failures in tolerogenic programs or stress signaling.