Expression of Extracellular Matrix in Hair Follicle Mesenchyme in Alopecia Areata

The study investigated the expression of extracellular matrix constituents in scalp biopsies from 14 patients with alopecia areata. It found that while non-lesional scalp follicles and miniature anagen follicles from bald patches showed normal expression of basement membrane proteins and proteoglycans, some large anagen follicles from lesional sites exhibited a loss of normal staining for chondroitin-6-sulphate in the dermal papilla. Additionally, lesional catagen follicles displayed marked convolution and thickening of the glassy membranes, which stained strongly for laminin and type IV collagen but weakly for interstitial collagens. This suggested a disturbance in mesenchymal function in alopecia areata.