A STUDY OF HTLV-1-RELATED DISEASES BY MEANS OF HIGHLY SENSITIVE HISTOCHEMISTRY

本研究旨在通过高灵敏度的组织化学方法观察HTLV-1相关疾病，特别是成人T细胞白血病/淋巴瘤（ATLL）的发病机制。整合的HTLV-1前病毒DNA是通过高灵敏度组织化学检测的第一个靶标。但是，由于常规处理组织的石蜡切片中DNA链的降解，前病毒DNA不是在切片中检测的良好靶标。我们建立了HTLV-1 p40 Tax（Tax）、p27雷克斯（REx）和细胞周期G1/S转换转录因子的高灵敏度免疫组化。应用高灵敏度免疫组化方法，研究Tax和雷克斯的表达与ATLL细胞表型转化的关系，以及与细胞周期G1/S期转录因子表达的关系。ATLL细胞表达的雷克斯明显多于Tax。ATLL细胞在细胞生长和增殖的所有阶段均不表达Tax。Tax和雷克斯的高敏感性组织化学检测有助于ATLL与其他T细胞淋巴瘤的鉴别诊断。ATLL细胞表现出E2 F家族在细胞核中的过表达或不表达，而欧洲无HTLV-1感染的T细胞淋巴瘤病例表现出细胞周期蛋白E的过表达。ATLL细胞表达少量Tax，在少量细胞核中弱表达cyclin E。提示HTLV-1致ATLL的白血病作用主要是通过细胞增殖信号转导系统完成的，该信号转导系统最终在G1/S转换时将E2 F从视网膜母细胞瘤蛋白释放到细胞核。另一方面，ATLL细胞在细胞周期中表现出压倒性的检查点异常，在细胞核中表达大量的E2 F，甚至在某些情况下在细胞周期的S期。认为在ATLL细胞中弱表达的Tax诱导细胞核中细胞周期蛋白E的弱表达，尽管细胞周期蛋白E的这种表达被认为是保留的细胞功能的一部分。

This study aimed to see pathogenesis of HTLV-1-related diseases, especially adult T-cell leukemia/lymphoma (ATLL) by means of highly-sensitive histochemistry. Integrated HTLV-1 proviral DNA is the first target to be detected by means of the highly-sensitive histochemistry. But, because of degradation of DNA strands in paraffon sections of routinely processed tissue, the proviral DNA is not a good target to be detected in the sections. We established highly sensitive immunohistochemistry of HTLV-1 p40Tax (Tax), p27Rex (REx), and transcription factors in G1/S transition of cell cycle. By means of the highly-sensitive immunohistochemistry, the relation of expression of Tax and Rex and to the phenotypic transformation in ATLL cells, and to the expression of the transcription factors in G1/S transition of cell cycle. ATLL cells expressed much more Rex than Tax. ATLL cells did not expressed Tax in all phases of cell growth and proliferation. Highly-sensitive histochemical detection of Tax and Rex is useful in the differential diagnosis of ATLL from the other T-cell lymphomas. ATLL cells showed overexpression of one of E2F families in nucleus or no expression of them, whereas European cases of T-cell lymphomas without HTLV-1 infection showed overexpression of cyclin E. Expressing a small amount of Tax, ATLL cells expressed weakly cyclin E in asmall number of nuclei. Consequently, it was suggested that HTLV-1 leukemogenesis of ATLL focuses on the proliferation signal transduction system that ends to release E2F from retinoblastoma protein to nucleus in G1/S transition. On the other hand, ATLL cells suggested over-riding checkpoint abnormality in cell cycle, expressing a large amount of E2F in nuclei even in S phase of cell cycle in some cases. Tax expressed weakly expressed in ATLL cells was thought to induce weak expression of cyclin E in nucleus, although this expression of cyclin E is thought to be a part of preserved cell function.