382 Environmental pathobiology of frontal fibrosing alopecia (FFA): Does linalool promote FFA development and progression by inducing epithelial hair follicle stem cell damage and MICA expression in the bulge?

Frontal fibrosing alopecia (FFA) is the most common cicatricial alopecia, whose prevalence has greatly increased, mainly in post-menopausal women, results from irreversible epithelial hair follicle (HF) stem cell (eHFSC) damage. Exposure to ingredients commonly found personal care products might trigger FFA-related immune responses. In fact, 76.2% of patients with FFA and/or LPP show type IV sensitization allergens these products. Since terpene fragrant, linalool, one identified patients, we have probed hypothesis that linalool may promote bulge HF privilege (IP) collapse eHFSC damage, i.e. core elements pathogenesis. Here report preliminary evidence exposing healthy human scalp HFs 1% organ culture decreased number K15+ eHFSCs and their K15 expression, although MHC class Ia expression was not upregulated. Importantly, increased “distress” signal, MICA, which can activate pathogenic MICA-NKG2D interactions IFNg secretion by FFA-pathogenic CD8+ T cells. Linalool also perifollicular CD68+ macrophages ex vivo, while transcription chemokine, CXCL9, lesional compared non-lesional biopsies (RNAseq). When were exposed this up-regulated significantly reduced eHFSCs, induced co-expression vimentin, indicating promotes pathological EMT eHFSCs. Thus, selected product indeed pathobiology events are thus best avoided.