Department of Pathology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.
Arch Pathol Lab Med. 2010 Jan;134(1):95-102. doi: 10.5858/2008-0699-OAR.1.
Specific differentiation of leukemia cutis (LC) from nonleukemic dermatoses is crucial to ensure proper treatment for the disease. Because of the exceptionally variable histologic features of LC and the frequent nonleukemic dermatoses in leukemia patients, identification of leukemic cells that infiltrate skin lesions is important. Here, we introduce JL1, a novel leukemia-associated surface antigen, which is not expressed in mature human tissue but in cortical thymocytes and small subpopulations of bone marrow hematopoietic precursors.
To assess the expression pattern of JL1 in LC and compare it with other commonly used markers. Also, to evaluate the expression of JL1 in other cutaneous lesions that need differential diagnoses.
Immunohistochemical staining with anti-JL1 and other commonly used markers for LC was performed on paraffin-embedded skin biopsies from 32 cases of LC with acute lymphoblastic leukemia/lymphoma and acute myelogenous leukemia. Immunohistochemical staining score was evaluated in each case according to the proportion of positive tumor cells found. JL1 staining was also done on 96 reactive or neoplastic cutaneous lesions.
JL1 was detected in 7 of 11 acute lymphoblastic leukemia/lymphoma LC (63.6%) and 7 of 21 acute myelogenous leukemia LC (33.3%), with invariably high-staining scores. None of the other cutaneous lesions or normal tissues expressed JL1. The expression pattern of JL1 was not altered in 2 patients with follow-up biopsies.
Our finding that JL1 is expressed exclusively and stably by leukemic cells suggests that it can be used as a useful adjunctive marker for initial diagnosis and follow-up biopsy of LC, particularly in cases of scarce infiltrates.
准确区分白血病皮肤浸润（LC）和非白血病性皮肤病对于确保疾病的恰当治疗至关重要。由于 LC 的组织学特征异常多变，且白血病患者中常伴有非白血病性皮肤病，因此识别浸润皮肤病变的白血病细胞非常重要。在此，我们介绍一种新型的白血病相关表面抗原 JL1，其在成熟的人体组织中不表达，但在皮质胸腺细胞和骨髓造血前体细胞的小亚群中表达。
评估 JL1 在 LC 中的表达模式，并与其他常用标志物进行比较。同时，评估 JL1 在其他需要鉴别诊断的皮肤病变中的表达情况。
对 32 例急性淋巴细胞白血病/淋巴瘤和急性髓细胞白血病 LC 的石蜡包埋皮肤活检进行抗 JL1 免疫组织化学染色和其他常用于 LC 的标志物的免疫组织化学染色。根据阳性肿瘤细胞的比例对每个病例进行免疫组织化学染色评分评估。还对 96 例反应性或肿瘤性皮肤病变进行了 JL1 染色。
在 11 例急性淋巴细胞白血病/淋巴瘤 LC 中有 7 例（63.6%）和 21 例急性髓细胞白血病 LC 中有 7 例（33.3%）检测到 JL1，其染色评分始终很高。其他皮肤病变或正常组织均未表达 JL1。在 2 例有随访活检的患者中，JL1 的表达模式没有改变。
我们发现 JL1 仅由白血病细胞稳定表达，这表明它可作为 LC 初始诊断和随访活检的有用辅助标志物，特别是在浸润程度较低的情况下。
