Plucked hair follicles from patients with chronic discoid lupus erythematosus show a disease-specific molecular signature

When faced with clinical symptoms of scarring alopecia – the standard diagnostic pathway involves a scalp biopsy which is an invasive and expensive procedure. Furthermore, clinical activity of scarring alopecias is often difficult to assess as symptoms of permanent damage and signs of activity can overlap or be difficult to distinguish. Here we report that gene expression analysis of only a small number of hair follicles (HF) plucked from lesional areas of the scalp is sufficient to characterise chronic discoid lupus erythematosus (CDLE). Lesional and non-lesional HFs were extracted from the scalp of patients with CDLE, psoriasis and healthy controls. The expression profile from CDLE HFs coincides with published profiles of CDLE from skin biopsy and was consistent with histopathological diagnostic features of CDLE. We therefore propose that information obtained from this non-invasive approach are sufficient to diagnose scalp LE. Human hair follicles (HFs) from 4 healthy individuals (male and female aged 22-55), 7 patients with CDLE (female aged 20-75) from both lesional and non-lesional areaswere plucked out. The hair shaft was cut off and the white sheath (inner and outer root sheath) containing epidermal keratinocytes were used for this study. Plucked hair follicles were embedded longitudinally in OCT and 3-5 µm thick frozen sections were cut using a cryostat and collected in RNase free universal tubes. This was followed by the addition of lysis buffer (ReliaPrep™ RNA Cell Miniprep System, Promega, Wisconsin, USA) to the cut hair follicle sections and stored on dried ice prior to RNA extraction, which was carried out according to the manufacturer’s protocol.