Department of Pathology, Hacettepe University, Ankara, Turkey.
Am J Dermatopathol. 2020 Apr;42(4):261-264. doi: 10.1097/DAD.0000000000001473.
Leukonychia, or whitening of the nail plate, is a common disease that was first described in 1919. Leukonychia is classified as acquired or congenital and may be due to abnormality of the nail bed (pseudoleukonychia) or nail plate (true leukonychia). The distal whitened area of the nail plate was clipped from a 31-year-old woman with striated leukonychia and a 32-year-old man and 34-year-old woman with punctate leukonychia. Routine hematoxylin and eosin staining of all clipped samples was performed. A piece of nail with leukonychia and a normal nail from case 2 were sent to the Mayo Clinic for mass spectrometric analysis. On hematoxylin and eosin examination, all leukonychia samples showed odd-appearing eosinophilic linear parakeratinization in the mid-segment of the nail plate. Mass spectrometric analysis of case 2 revealed serum proteins (albumin, serotransferrin IgG, gamma chain, IgG lambda chain, and haptoglobulin) and hair proteins that were not found in the keratin content of the normal nail (keratin type Ha1 and cuticular keratin Ha4). This is the first description of odd-appearing linear parakeratosis and the first proteomic analysis showing abnormal protein content in acquired leukonychia.
甲白，即指甲板变白，是一种常见疾病，于 1919 年首次被描述。甲白分为获得性和先天性，可能是由于甲床（伪甲白）或甲板（真甲白）异常所致。从一位患有条纹状甲白的 31 岁女性、一位患有点状甲白的 32 岁男性和一位 34 岁女性的指甲远端发白区域剪下指甲样本。对所有剪下的样本进行常规苏木精-伊红染色。将来自病例 2 的一片甲白和一片正常指甲送到梅奥诊所进行质谱分析。苏木精-伊红检查显示，所有甲白样本的甲板中段均出现外观异常的嗜酸性线状不全角化。对病例 2 的质谱分析显示血清蛋白（白蛋白、转铁蛋白 IgG、γ 链、IgG λ 链和触珠蛋白）和头发蛋白在正常指甲的角蛋白含量中未发现（角蛋白类型 Ha1 和表皮角蛋白 Ha4）。这是首次描述外观异常的线状不全角化，也是首次进行蛋白质组学分析显示获得性甲白中存在异常蛋白含量。
