Norris A, Todd C, Graham A, Quinn A G, Thody A J
Department of Dermatology, University of Newcastle upon Tyne, U.K.
Br J Dermatol. 1996 Feb;134(2):299-306.
The proto-oncogene c-kit encodes the transmembrane tyrosine kinase receptor that has a role in the growth regulation of various cell types including melanocytes. In the present study we have examined the expression of the c-kit protein in the skin of seven patients with vitiligo. Melanocytes positive for c-kit protein were observed in the basal layer in non-lesional skin and the mean number of 25.8 +/- 5.2 (per 200 basal cells) compared with that of 21.8 +/- 3.5 from six control subjects. In perilesional skin there was a reduction in the numbers of c-kit positive melanocytes (6.7 +/- 2.6) and this was especially noticeable in six of the seven patients. Such a reduction was less obvious following staining with MEL-5 and in only two subjects were the numbers of melanocytes below the normal range. This suggests that the reduction in c-kit staining was the result of decreased expression of the protein rather than a loss of melanocytes. No melanocytes, positive for c-kit protein, or after staining with MEL-5, were identified in lesional skin although isolated tyrosinase-positive melanocytes were seen in one subject. There was no apparent change in the numbers of mast cells expressing c-kit protein and the intensity of staining in the dermis even in lesional skin was similar to that in the controls. These results demonstrate that c-kit protein is present on melanocytes in adult human skin and that in perilesional skin of some vitiligo patients there is a reduction in the numbers of melanocytes expressing this receptor. Whether this may contribute to the defective melanocyte growth and/or survival that occurs in vitiligo or whether it is a consequence of melanocyte damage remains to be seen.
原癌基因c-kit编码跨膜酪氨酸激酶受体，该受体在包括黑素细胞在内的多种细胞类型的生长调节中发挥作用。在本研究中，我们检测了7例白癜风患者皮肤中c-kit蛋白的表达情况。在非皮损区皮肤的基底层观察到c-kit蛋白阳性的黑素细胞，其平均数量为25.8±5.2（每200个基底细胞），而6名对照受试者的平均数量为21.8±3.5。在皮损周边皮肤中，c-kit阳性黑素细胞数量减少（6.7±2.6），这在7例患者中的6例中尤为明显。用MEL-5染色后这种减少不太明显，只有2名受试者的黑素细胞数量低于正常范围。这表明c-kit染色减少是蛋白表达降低的结果，而非黑素细胞丢失。在皮损区皮肤中未发现c-kit蛋白阳性的黑素细胞，用MEL-5染色后也未发现，尽管在1名受试者中可见孤立的酪氨酸酶阳性黑素细胞。表达c-kit蛋白的肥大细胞数量没有明显变化，即使在皮损区皮肤中真皮的染色强度也与对照组相似。这些结果表明，c-kit蛋白存在于成人皮肤的黑素细胞上，并且在一些白癜风患者的皮损周边皮肤中，表达该受体的黑素细胞数量减少。这是否可能导致白癜风中黑素细胞生长和/或存活缺陷，或者它是否是黑素细胞损伤的结果，还有待观察。
