Stem Cell Markers (Cytokeratin 15, CD34, and Nestin) in Primary Scarring and Nonscarring Alopecia

In the 2009 study by Hoang, Keady, and Mahalingam, 50 cases of scarring alopecia and 34 cases of nonscarring alopecia were examined for the presence of stem cell markers CK15, CD34, and nestin. CK15 was found in 53% of scarring alopecia cases and 100% of nonscarring cases, CD34 in 69% of scarring versus 100% of nonscarring cases, and nestin was more variably expressed, with higher presence in the infundibular region of scarring alopecia cases (39%) compared to nonscarring cases (22%). The study concluded that scarring alopecia targets not only the follicular bulge stem cells but also stem cells in the inner and outer aspects of the ORS, and that the increased expression of nestin in scarring alopecia indicates the infundibular region as a potential source of stem cells for treatment. The findings support the idea that there are distinct stem cell populations within the hair follicle, which may be involved in hair follicle development and could be targeted for alopecia therapies.