Ji-Hye Park1, Dong-Youn Lee1, Kee-Taek Jang2, Sang-Yun Ha2, Ghee Young Kwon2, Kyung-Hoon Lee3, Jong Sup Shim4, Eun Ji Kwon5. 1. Department of Dermatology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Gangnam-gu, South Korea. 2. Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Gangnam-gu, South Korea. 3. Department of Anatomy, Samsung Medical Center, Sungkyunkwan University School of Medicine, Gangnam-gu, South Korea. 4. Department of Orthopedic Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Gangnam-gu, South Korea. 5. Dermpath Diagnostics, Port Chester, New York.
Abstract
BACKGROUND: We previously demonstrated the presence of onychodermis, a specialized mesenchymal cell population beneath the nail matrix and proximal nail bed demonstrating CD10 expression. We hypothesize that the onychodermis could be the nail analog of the follicular dermal papilla, which is known to express CD13. We compare CD13 expression patterns between specialized mesenchymes of nail and hair, and compare these findings with CD10 expression patterns. METHODS: CD10 and CD13 immunohistochemistry was performed on polydactyly and adult cadaveric nail units, and on hair follicles in scalp nevus sebaceus excision specimens. RESULTS: CD10 and CD13 were expressed in the mesenchyme below the nail matrix and nail bed. Stronger CD13 expression was observed in the mesenchyme containing onychofibroblasts below the nail matrix compared with that below the nail bed. CD10 was expressed in the dermal sheath of terminal hair follicles, but it was expressed in the dermal sheath and follicular dermal papilla of primitive hair follicles within nevus sebaceus lesions. CD13 was expressed in the dermal sheath and dermal papilla of terminal and primitive hair follicles. CONCLUSION: CD13 may be a marker for onychofibroblasts within nail matrix onychodermis. We demonstrate CD13 expression in the specialized mesenchymes of both nail and hair.
BACKGROUND: We previously demonstrated the presence of onychodermis, a specialized mesenchymal cell population beneath the nail matrix and proximal nail bed demonstrating CD10 expression. We hypothesize that the onychodermis could be the nail analog of the follicular dermal papilla, which is known to express CD13. We compare CD13 expression patterns between specialized mesenchymes of nail and hair, and compare these findings with CD10 expression patterns. METHODS:CD10 and CD13 immunohistochemistry was performed on polydactyly and adult cadaveric nail units, and on hair follicles in scalp nevus sebaceus excision specimens. RESULTS:CD10 and CD13 were expressed in the mesenchyme below the nail matrix and nail bed. Stronger CD13 expression was observed in the mesenchyme containing onychofibroblasts below the nail matrix compared with that below the nail bed. CD10 was expressed in the dermal sheath of terminal hair follicles, but it was expressed in the dermal sheath and follicular dermal papilla of primitive hair follicles within nevus sebaceus lesions. CD13 was expressed in the dermal sheath and dermal papilla of terminal and primitive hair follicles. CONCLUSION:CD13 may be a marker for onychofibroblasts within nail matrix onychodermis. We demonstrate CD13 expression in the specialized mesenchymes of both nail and hair.