进行性斑状色素减少症的临床及实验研究

目的 探讨进行性斑状色素减少症（PMH）的临床特点和诊断要点。方法 用Wood灯及活体共聚焦激光扫描显微镜（皮肤CT）观察皮损特点、致病菌培养、黑素细胞培养,并应用S-100和TRP-1免疫组化分析皮损区黑素细胞数量、电镜观察其超微结构特征。结果 Wood灯检查示皮损区可见点状红色荧光,皮肤CT观察示皮损区色素环完整,但与周围正常皮肤相比其内所含的黑素颗粒含量减少。致病菌培养可见产红色荧光的革兰阳性棒状杆菌,经鉴定为痤疮丙酸杆菌。S-100染色示皮损区阳性细胞数（8.25 ± 0.96）与周围正常皮肤（8.75 ± 1.71）相比无统计学意义（P > 0.05）。TRP-1染色示皮损区阳性细胞数（4.25 ± 0.96）与周围正常皮肤（4.50 ± 1.29）相比也无统计学意义（P > 0.05）。电镜观察发现,皮损区Ⅳ期黑素小体的数量明显下降,并观察到较多的膜结合体,内含成簇状分布的多个体积较小的Ⅱ ～ Ⅳ期黑素小体。成功培养出黑素细胞,其形态与正常细胞相比未见明显异常。结论 初步提出进行性斑状色素减少症的诊断要点。     

葛根素促进黑素细胞黑素合成及其机制的初步探讨

目的 探讨葛根素对正常人黑素细胞黑素合成的影响和可能机制。 方法 用噻唑蓝（MTT）法、NaOH裂解法观察葛根素对黑素细胞增殖及黑素合成作用,RT-PCR及Western印迹法检测葛根素对黑素细胞小眼畸形相关转录因子（MITF）、酪氨酸酶（TYR）、酪氨酸酶相关蛋白1（TRP-1）基因转录和蛋白表达水平的影响。 结果 1 ~ 40 μmol/L浓度范围内葛根素对体外培养的黑素细胞增殖影响与正常对照组相比,差异无统计学意义（P > 0.05）。与正常对照组相比,40 μmol/L葛根素可显著促进黑素细胞的黑素合成（P < 0.05）,并可显著增加MITF、TYR、TRP-1 mRNA及蛋白的表达（P < 0.05）。40 μmol/L葛根素使MITF、TYR、TRP-1的蛋白表达量分别比正常对照组增加8.69%,10.28%和10.58%（P < 0.05）;并使MITF、TYR、TRP-1的mRNA表达量分别比正常对照组增加2.48倍,1.91倍和1.63倍（P < 0.05）。 结论 葛根素能增加MITF、TYR、TRP-1 mRNA及蛋白的表达水平,促进黑素合成。     

白癜风复色区黑素细胞特异性抗原表达的研究

目的：研究白癜风复色区黑素细胞分布及gp100、酪氨酸酶（TYR）等抗原的表达。方法：对白癜风患者复色区皮肤活检的组织标本以免疫组化染色识别gp100、TYR、酪氨酸酶相关蛋白（TRP）-1和TRP-2,以HPIAS-1000彩色病理图文报告系统定量分析阳性表达的强弱。结果：色素脱失斑处未见活性黑素细胞,复色区黑素细胞数目与正常人皮肤比较差异无统计学意义（P〉0．05）。色素脱失斑内岛状复色区皮肤,近毛囊部位黑素细胞数目较多,远离毛囊部位数目较少;色素脱失斑边缘复色区内,黑素细胞在表皮及毛囊的基底层中分布较均匀。复色区黑素细胞树突短粗、数目变少。复色区阳性细胞gp100和TRP-2图像灰度值与正常皮肤比较差异无统计学意义（P〉0．05）,TYR低于正常皮肤（P〈0．05）,而TRP-1明显低于正常皮肤（P〈0．01）。结论：色素脱失斑处有功能黑素细胞缺失。复色区内可见黑素细胞,其结构、功能皆完整,数目与正常人无明显差别。复色区黑素细胞可能来源于毛囊组织．亦可能来源于色素脱失斑边缘正常黑素细胞。TRP-1的高表达可能导致复色区黑素细胞的形态异常。     

表没食子儿茶素没食子酸酯对人表皮黑素细胞黑素合成的影响及机制

目的：观察表没食子儿茶素没食子酸酯（EGCG）对体外培养的人表皮黑素细胞的黑素合成和酪氨酸酶（TYR）活性以及TYR、酪氨酸酶相关蛋白（TRP）-1、TRP-2mRNA表达的影响,探讨EGCG对黑素合成的影响及其作用机制。方法：选择5．0、10．0、12．5、15．0、20．0μg／mL5个浓度的EGCG作用于体外培养的人表皮黑素细胞72h,分别测定细胞增殖活性、TYR活性、黑素含量;采用逆转录（RT）-PCR半定量检测EGCG对黑素细胞中TYR、TRP-1、TRP-2 mRNA表达的影响。结果：EGCG显著抑制黑素合成和TYR活性,且呈浓度依赖性;EGCG可明显抑制黑素细胞中TYR mRNA和TRP-1 mRNA的表达,但对TRP-2mRNA的表达无明显影响。结论：EGCG可抑制黑素合成和TYR活性,这种作用可能与EGCG下调TYR和TRP-1的表达有关。     

倍他米松对毛囊外毛根鞘无色素黑素细胞激活的试验研究

目的：研究倍他米松（betamethasone，BT）对毛囊无色素黑素细胞（amelanotic melanocytes，AMMC）的激活作用。方法：以高、中、低3种不同浓度的BT作用于培养的人毛囊外毛根鞘AMMC，测定药物作用前后酪氨酸酶（tyrosinase，TYR）活性和黑素生成的变化。通过间接免疫荧光法结合激光共聚焦显微镜半定量分析药物作用前、后AMMC TYR、酪氨酸酶相关蛋白（tyrosinase related protein，TRP）-1和TRP-2表达的变化，透射电镜分析黑素小体在药物作用前后的变化。结果：BT促进了AMMC表达TYR和TRP-1，并且以剂量依赖方式促进TYR活性，诱导黑素生成。AMMC主要含有Ⅰ、Ⅱ和Ⅲ期黑素小体，但是BT作用后AMMC含有大量Ⅲ或Ⅳ期黑素小体，并且以Ⅳ期黑素小体为主。结论：BT能够激活AMMC，这可能部分解释了糖皮质激素治疗白癜风的机制。     

体外培养节段型白癜风样无色素痣皮损黑素细胞及其临床意义

【摘要】 目的 评价负压吸疱表皮黑素细胞培养对节段型白癜风样无色素痣的辅助诊断价值。方法 收集2019年6月至2020年3月于杭州市第三人民医院皮肤科依据Coupe标准临床诊断的8例节段型白癜风样无色素痣患者,进行伍德灯、反射式共聚焦显微镜（RCM）检查,308 nm准分子激光试验,负压吸疱获取表皮黑素细胞并培养,记录结果。结果 8例患者中,6例皮损伍德灯下可见荧光,4例RCM下可见色素环完整性缺失,5例经308 nm准分子激光照射试验后未见复色反应。8例患者体外培养的皮损黑素细胞硫酸亚铁染色均阳性,经消化离心后沉淀呈黄白色,电镜下黑素细胞胞质内可见Ⅰ~ Ⅲ期黑素小体;皮损对侧同一解剖部位正常皮肤黑素细胞沉淀则呈黑色,电镜下黑素细胞胞质内可见Ⅰ~ Ⅳ期黑素小体。结论 负压吸疱表皮黑素细胞培养有助于诊断节段型白癜风样无色素痣。     

人毛囊无色素黑素细胞培养方法的改良及色素生成相关酶表达的研究

目的进一步改良人毛囊无色素黑素细胞（amelanotic melanocytes，AMMC）培养的方法，并研究了AMMC内黑素生成相关酶的表达：酪氨酸酶（tyrosinase,TYR）、酪氨酸酶相关蛋白-1（tyrosinase related protein-1，TRP—1）和酪氨酸酶相关蛋白-2（tyrosinase related protein-1，TRP-2）。方法采用1％分离酶（dispase）消化分离毛囊，选用含干细胞因子（stem cell factor，SCF）、内皮素-3（endothelin-3，ET-3）、碱性成纤维细胞生长因子（basic fibroblast grow factor，bFGF）和霍乱毒素（cholera toxin，CT）的成黑素细胞培养基培养AMMC，同时培养表皮黑素细胞（melanocytes，MC）作为对照，采用免疫组化、多巴染色和透射电镜对细胞进行鉴定，蛋白印记法分析TYR、TRP-1和TRP-2的表达。结果1％分离酶消化24h可以容易获得游离的毛囊，结合我们所用的培养基完全排除了成纤维细胞的污染。所用成黑素细胞培养基促AMMC增殖明显，细胞可传5代以上。免疫组化结果显示，AMMC表达gp100、酪氨酸酶（tyrosinase，TYR）、酪氨酸酶相关蛋白-1（tyrosinase related proteifl-1，TRP-1）和酪氨酸酶相关蛋白-2（tyrosinase related protein-1，TRP-2），证明培养的细胞为黑素细胞。AMMC的多巴染色呈阴性，并且透射电镜发现AMMC胞质中仅含大量的Ⅰ期、Ⅱ期黑素小体，未见Ⅲ、Ⅳ期黑素小体，因此说明AMMC处于未分化状态。TYR和TRP-1在MC中的表达明显强于AMMC。TRP-2的表达在两种细胞间没有明显差别，进一步说明AMMC与MC具有异质性。结论我们成功培养了完全纯化、快速增殖的AMMC，并且培养的细胞不能生成黑素，生物学性状更接近活体中的状态，其与表皮黑素细胞具有异质性。     

毛乳头细胞对毛囊前体黑素细胞作用的评价

目的：确定毛乳头细胞（DPC）对毛囊前体黑素细胞（MP）的激活和趋化作用。方法：采用三维分离式共培养体系,将MP与毛囊外毛根鞘角质形成细胞（KC）以1：10比例于6孔培养板中接触式共培养,DPC以1×10^6个／孔分离培养于Transwell inserts。检测DPC对MP的趋化作用。MP内黑素小体、酪氨酸酶（TYR）、酪氨酸酶相关蛋白1（TRP-1）和酪氨酸酶相关蛋白2（TRP-2）的表达。结果：MP与KC共培养后MP内出现Ⅲ期黑素小体,当三种细胞共培养后MP内主要为Ⅲ和Ⅳ期黑素小体。DPC可促进MP中TYR和TRP-1的表达,但对TRP-2的表达无明显影响,对MP具有明显趋化作用。结论：构建了MP、KC和DPC的三维培养体系,发现DPC对MP具有明显激活和趋化移行作用。     

淫羊藿苷抑制正常黑素细胞黑素合成的研究

目的:观察中药单体淫羊藿苷对体外培养的正常黑素细胞黑素合成和酪氨酸酶活性的影响。方法:选择高、中、低3个浓度的中药单体作用于体外培养的黑素细胞,测定细胞酪氨酸酶活性、黑素含量和细胞增殖率。采用间接免疫荧光染色法对药物作用的黑素细胞和对照的酪氨酸酶(tyrosinase熏TYR)、酪氨酸酶相关蛋白-1(tyrosinaserelatedprotein-1熏TRP-1)、TRP-2进行标记,然后采用激光共聚焦显微镜半定量分析淫羊藿苷作用后细胞内3种成分表达量的变化。结果:淫羊藿苷明显抑制酪氨酸酶活性和黑素的生成(P<0.01),且呈浓度依赖性,但淫羊藿苷抑制黑素生成的作用较氢醌弱(P<0.01);淫羊藿苷以浓度依赖的方式促进细胞的增殖,氢醌则抑制了细胞的增殖;淫羊藿苷对黑素细胞内TYR和TRP-2的表达没有明显影响,但是对TRP-1的表达却明显增加了。结论:淫羊藿苷能够抑制黑素合成和酪氨酸酶活性,这种抑制可能主要通过抑制酪氨酸酶活性起作用。     

1,25二羟基维生素D3对毛囊外毛根鞘无色素黑素细胞激活的实验研究

目的研究1,25二羟基维生素D3(1,25-Dihydroxyvitamin D3,VID)对毛囊外毛根鞘无色素黑素细胞(amelanotic melanocytes,AMMC)的激活作用。方法以高、中、低3种不同浓度的1,25(OH)2D3作用于培养的人毛囊外毛根鞘AMMC,倒置显微镜观察细胞形态的变化,然后收集细胞,测定细胞酪氨酸酶活性和黑素含量,透射电镜观察药物作用前后AMMC内黑素小体的变化,最后通过Western blot方法半定量分析药物作用前后AMMC内酪氨酸酶(tyrosinase,TYR)、酪氨酸酶相关蛋白1(tyrosinase related protein-1,TRP-1)和酪氨酸酶相关蛋白2(tyrosinase relatedprotein-2,TRP-2)表达的变化。结果 VID能增加AMMC内酪氨酸酶活性,促进AMMC生成黑素,电镜结果显示药物作用后的AMMC内出现大量Ⅲ、Ⅳ期黑素小体。Western blot结果显示VID可以促进AMMC中TYR和TRP-1的表达,但对TRP-2的表达无明显影响。结论 VID通过促进黑素生成相关酶TYR和TRP-1的表达激活了AMMC。     

Histopathologic features in vitiligo

Nevus depigmentosus is a congenital disorder characterized by a nonprogressive hypopigmented lesion, which may not be apparent at birth. Thus, it is sometimes difficult to differentiate vitiligo from nevus depigmentosus only by clinical features. We postulated that the histologic changes in lesional and perilesional skin might be different in the 2 conditions. We took biopsies from both lesional and perilesional skin of 100 cases of vitiligo to assess the number of melanocytes, the amount of melanin, dermal inflammatory infiltrate, and other changes. We compared them with 30 cases of nevus depigmentosus. Histologically, lesions of vitiligo showed more basal hypopigmentation and dermal inflammation than perilesional normal skin. With Fontana-Masson staining, 16% of cases of vitiligo showed the presence of melanin. The ratio of pigmented area to epidermal area was 0.06% in vitiligo, whereas 17% in perilesional normal skin and 8.9% in nevus depigmentosus. In NKI/beteb staining, 12% of vitiligo showed the presence of melanocytes, and their average number was 7.68 per square millimeter. The number of melanocytes was also decreased in nevus depigmentosus but not as much as in vitiligo. We also confirmed the presence of melanocytes in 1 of 3 cases of vitiligo by electron microscopy. In conclusion, there are a few melanocytes and melanin in some cases of vitiligo. Therefore, the diagnosis of vitiligo should be made considering these points.     

白癜风皮损边缘黑素细胞线粒体超微结构的电镜观察

【摘要】 目的 探讨白癜风患者皮损边缘黑素细胞线粒体结构的变化。方法 在透射电镜下观察健康对照、进展期白癜风及稳定期白癜风患者皮损边缘黑素细胞形态,体视学方法测量线粒体体密度（Vv）、表面积密度（Sv）、数密度（Nv）等参数。结果 健康对照组黑素细胞可见大量黑素小体（28.57 ± 3.21）,以Ⅲ、Ⅳ期为主,线粒体规则分布在细胞内,结构正常、嵴密集,部分细胞胞质内可见自噬小体。进展期和稳定期白癜风黑素细胞内黑素小体数量减少,单位细胞内黑素小体数量分别为22 ± 6.16和17.43 ± 6.24,其中,Ⅲ期黑素小体显著减少,线粒体大小不一、形态多样,大部分线粒体明显肿胀,嵴模糊、排列紊乱甚至断裂,呈空泡状改变,未见线粒体自噬现象。线粒体形态结构定量研究显示,健康对照组Nv、Vv、Sv分别为（7.194 ± 1.434） μm－3、（4.8 ± 1.2）%、（2.42 ± 0.86） μm－1;进展期白癜风组Nv、Vv、Sv分别为（4.055 ± 0.906） μm－3、（7.4 ± 2.1）%、（3.58 ± 1.15） μm－1;稳定期白癜风组Nv、Vv、Sv分别为（5.311 ± 0.873） μm－3、（6.5 ± 1.4）%和（2.82 ± 0.94） μm－1,组间差异有统计学意义（P ＜ 0.05）。结论 白癜风皮损边缘黑素细胞线粒体受损,且进展期损伤程度大于稳定期。 【关键词】 白癜风; 黑素细胞; 线粒体; 显微镜检查,电子,透射     

白癜风表皮黑素细胞超微结构及小眼畸形相关转录因子转录调控研究

目的 研究白癜风黑素细胞超微结构和小眼畸形相关转录因子 （MITF）及其转录调控的酪氨酸酶相关蛋白（TRP）与白癜风临床类型与病程的相关性。方法 选择不同病程的寻常型白癜风（VV）12例和节段型白癜风（SV）8例,分别取白斑区、白斑边缘正常肤色区和远离白斑正常肤色区的表皮片,经组织学确定其表皮的完整性。透射电镜观察10例患者（VV 6例,SV 4例）不同区表皮黑素细胞的超微结构特点。对所有20例远离白斑正常肤色区的表皮片黑素细胞进行培养,应用免疫印迹方法检测 MITF及其转录调控的酪氨酸酶（TYR）、酪氨酸酶相关蛋白1（TYRP1）和酪氨酸酶相关蛋白2（TYRP2）的表达水平。结果 白癜风表皮黑素细胞超微结构病理改变：10例中7例白斑区表皮内未见黑素细胞,1例短病程和2例长病程VV分别可见少量黑素体显著减少或缺失的黑素细胞;白斑边缘正常肤色区,6例VV中,3例病程小于15个月者可见黑素细胞超微结构异常,而4例SV中仅1例异常;远离白斑正常肤色区,10例黑素细胞超微结构均正常。白癜风表皮黑素细胞MITF及其转录调控TRP的表达：VV的MITF表达下调与TYR、TYRP1、TYRP2的表达下调一致;SV存在MITF显著表达下调,而TYR、TYRP1、TYRP2几均正常表达。结论 VV和SV可能存在不同的表皮黑素细胞超微结构病理改变和MITF转录调控机制。     

Possible mechanisms of hypopigmentation in lichen sclerosus

Lichen sclerosus (LS) shares with vitiligo a milky-white appearance. By biopsy, pathognomonic dermal sclerosis readily distinguishes LS from vitiligo and other causes of leukoderma. To determine what the mechanism of hypopigmentation is in LS, we examined samples from LS cases for alterations in melanin content (Fontana-Masson stain) and melanocyte number (HMB-45 [PMEL-17/gp100], Mel-5 [TRP-1], Mart-1 [Melan A]) and compared these findings with those in controls of normal skin, acute scars, vitiligo, and lichen planus (LP; a common inflammatory cause of hyperpigmentation). The degree and extent of melanization found in LS overlapped with that in acute scars showing predominantly hypomelanized keratinocytes, with that in LP containing regions with numerous melanophages, and with that in vitiligo exhibiting focal regions of keratinocytes devoid of melanin pigment. By hematoxylin-eosin staining and immunocytochemistry for Mel-5 and Mart-1, LS had a lower mean count of melanocytes than acute scars, LP, and normal skin per 200 basal keratinocytes. In addition, a few LS cases had a significant loss of melanocytes comparable to that of vitiligo. Surprisingly, Mart-1 identified rare melanocytes in 67% of vitiligo cases and a significantly larger pool of melanocytes in LS and controls other than those labeled by Mel-5. Furthermore, LP and evolving lesions of LS contained the highest Mart-1 counts. HMB-45-immunoreactive melanocytes were found in the majority of acute scars and in LP and late-stage LS lesions at significantly lower levels than Mel-5- and Mart-1- labeled melanocytes, but they were not found in vitiligo or normal skin. We propose that several mechanisms may play a role in the production of leucoderma in LS: 1) decreased melanin production; 2) block in transfer of melanosomes to keratinocytes; and 3) melanocyte loss. The latter finding may be the pathogenic connection (lichenoid dermatitis of LS triggering an autoimmune reaction to melanocytes) that underlies the documented association of LS with vitiligo.     

Hypopigmented keratosis: is it a hyperkeratotic variant of idiopathic guttate hypomelanosis?

We have occasionally seen patients with acquired well‐demarcated, scattered hypopigmented papules. In this study, we investigated the clinical and histopathological characteristics of such lesions. Biopsies were taken from the lesional and perilesional normal skin from 10 of 13 patients, which were compared with 10 idiopathic guttate hypomelanosis (IGH) samples. The lesions were scattered, well‐circumscribed, flat‐topped, hypopigmented papules. There was no age or gender predilection. Marked hyperkeratosis was present, with clear‐cut margins distinguishable from the adjacent normal epidermis. The melanin content was decreased in the lesional epidermis, which was associated with a decrease in expression of melanogenesis‐associated markers such as tyrosinase and NKI/beteb (marker of gp100) and reduction in the number of melanocytes. These histological findings were similar to those of IGH except for the additional finding of a thicker stratum corneum in this case seem to represent a ‘hyperkeratotic’ variant of IGH.     

Study of CCN3 (NOV) and DDR1 in normal melanocytes and vitiligo skin

We have hypothesised that melanocytes disappear in vitiligo because they are weakly attached to the epidermal basal membrane (melanocytorrhagy). In the epidermis, attachment of melanocytes to collagen IV is mediated through DDR1, which is under the control of CCN3. DDR1 genetic variants have been associated with vitiligo in patients of different ethnic origin. In vitro studies have shown that inhibition of CCN3 induces the detachment of melanocytes. We have studied in parallel the expression of CCN3 and DDR1 in lesional and perilesional skin of patients with vitiligo and the impact of the silencing of CCN3 and DDR1 in normal human melanocytes on their behaviour in epidermal reconstructs. Our in vivo study provides evidence of a dysregulation of the DDR1-CCN3 interaction in vitiligo skin as melanocytes remaining in perilesional skin did not express CCN3. Expression of DDR1 was decreased in lesional versus perilesional vitiligo skin in the majority of patients, and the expression of collagen IV was found decreased in all patients. Silencing of CCN3 in melanocytes induced a significant inhibition of cell adhesion to collagen IV whereas melanocytes transduced with shDDR1 still adhered well on collagen IV and did not increase melanocyte loss in epidermal reconstructs as compared with normal melanocytes. Melanocyte detachment was observed but not in all reconstructs using CCN3 silenced melanocytes. Overall, our study confirms that a downregulation of CCN3 is implicated in melanocyte adhesion in part through DDR1. In vitiligo skin, the interaction of CCN3 with other molecules, such as TGFβ and CCN2, needs to be addressed.     

Confetti‐like lesions with hyperkeratosis: a novel ultraviolet‐induced hypomelanotic disorder?

Confetti leucoderma can occur in a variety of unrelated skin disorders and is often a diagnostic challenge. We describe a 33-year-old man with a history of mycosis fungoides and vitiligo. He developed disseminated 1-2-mm round-shaped leucodermic lesions 6 months after psoralen photochemotherapy and 12 months after systemic therapy with interferon. The skin lesions had a discrete hyperkeratotic scale. Multiple skin biopsies and immunohistochemical studies showed lamellar orthohyperkeratosis, papillomatosis, hypomelanotic keratinocytes but a normal number of melanocytes. Langerhans cells, in contrast, were reduced in lesional skin. Electron microscopy disclosed only a few type I and II melanosomes in lesional melanocytes, while keratinocytes were largely devoid of any melanosomes. This constellation of clinical, immunohistochemical and ultrastructural findings has not been reported before and distinguishes our case from leucoderma punctatum, idiopathic guttate hypomelanosis and disseminated hypopigmented keratoses. We suggest that the skin lesions observed in our patient represent an unusual response to ultraviolet damage to melanocytes followed by reactive epidermal hyperkeratosis.     

Clinical and histopathologic characteristics of trichrome vitiligo

BACKGROUND: The term trichrome vitiligo describes lesions that have a tan zone of varying width between normal and totally depigmented skin, which exhibits an intermediate hue. However, the pathogenesis and the histopathologic characteristics of trichrome vitiligo are unknown. OBJECTIVE: Our purpose was to investigate the clinical and histopathologic characteristics and the pathogenesis of trichrome vitiligo. METHODS: Four punch biopsy specimens were taken from 21 patients with trichrome vitiligo; they were from vitiliginous skin, light brown skin, perilesional normal skin, and normal skin as far as 5 cm from the nearest vitiligo spot. The sections were stained with hematoxylin-eosin; in selected cases, we performed immunohistochemical staining with S-100 protein and CD1a. RESULTS: Trichrome vitiligo occurred most frequently on the trunk in active vitiligo vulgaris. Focal vacuolar degeneration of the basal cell layer and mild inflammatory cell infiltration of the epidermis and dermis were more prominent in light brown skin and perilesional normal skin than in vitiliginous skin and normal skin. The number of melanocytes was decreased in light brown skin compared with perilesional normal skin (P <.05) and in vitiliginous skin compared with light brown skin (P <.05); a few melanocytes were observed even in skin affected by trichrome vitiligo. The number of Langerhans cells was increased in the epidermis of light brown skin and perilesional normal skin compared with vitiliginous and normal skin (P <.05). PUVA therapy yielded excellent repigmentation. CONCLUSION: Trichrome vitiligo is a variant of active vitiligo. The changes of melanocytes, keratinocytes, and Langerhans cells may be involved in the pathogenesis of depigmentation in trichrome vitiligo.