Analysis of lymphomagenesis of NK lymphoma based on Epstein-Barr virus.

1.淋巴结T/NK细胞淋巴瘤的临床病理分析：我们对227例淋巴结T/NK细胞淋巴瘤进行了分析，并确定了细胞毒性分子阳性淋巴瘤。其中，发现细胞毒性分子（+）EBV（+）淋巴瘤病例，新归类为细胞毒性大T细胞淋巴瘤. NK/T细胞淋巴瘤衍生的细胞系HANK 1A的特征在无血清培养基中增殖的亚克隆选自NK/T细胞淋巴瘤衍生的细胞系HANK 1。这些细胞仅在高细胞浓度下增殖，在抗CD 56或抗CD 7单克隆抗体存在下死亡，而在人血浆存在下，该亚克隆对抗CD 56或抗CD 7单克隆抗体的生长抑制表现出抗性。由于胎牛血清对HANK 1的生长有不利影响，因此人血浆促生长活性与NK/T细胞淋巴瘤预后不良有关. HANK 1的DNA分型显示HLA-A（0207，2402），这在日本是流行的。我们正在选择针对HLA匹配的健康志愿者B细胞的细胞毒性T细胞克隆，B细胞是由EBV永生化的。EBV在淋巴结中的再激活机制通过分析EBV与淋巴结T/NK细胞淋巴瘤的关系，我们发现在血管免疫母细胞性淋巴结病伴异常蛋白血症（AILD）中，EBV的克隆性感染率较高。由于滤泡树突状细胞（FDC）在AILD中丰富，因此将EBV血清阳性AILD患者的淋巴结中的细胞与FDC衍生的细胞系共培养。我们获得了EBV感染的B细胞，其生长依赖于FDC衍生的细胞系。FDC在EBV再激活中的作用有待进一步研究。

1. Clinico-pathological analysis of nodal T/NK cell lymphomas.We characterized 227 cases of nodal T/NK cell lymphomas and established cytotoxic molecule positive lymphoma. Among them, we found cytotoxic molecule (+)EBV(+) lymphoma cases which were newly categorized as cytotoxic large T-cell lymphoma.2. Characterization of NK/T cell lymphoma derived cell line HANK1A sub-clone which proliferated in the serum-free media was selected from the NK/T cell lymphoma derived cell line HANK1. Those cells proliferated only in the high cell concentration, and died in the presence of anti-CD56 or anti-CD7 monoclonal antibody.However, in the presence of human plasma, this sub-clone showed the resistance to the growth inhibition of anti-CD56 or anti-CD7 monoclonal antibody. Because fetal calf serum had adverse effect on the growth of HANK1, growth promoting activity of human plasma suggested the relevance to the poor prognosis of NK/T cell lymphoma.3. Induction of cytotoxic T-cell clone against NK/T cell lymphomaThe DNA typing of HANK1 showed HLA-A (0207, 2402) which is popular in Japanese. We are selecting cytotoxic T-cell clones against HLA-matched healthyvolunteers' B-cells which are immortalized by EBV.4. Reactivation mechanism of EBV in lymph nodesFrom the analysis of the association of EBV to nodal T/NK cell lymphomas, we found high rate of clonal infection in angioimmunoblastic lymphadenopathy with dysproteinemia (AILD). As follicular dendritic cells (FDC) are abundant in AILD, cells in the lymph nodes of EBV-seropositive AILD patients were co-cultured with FDC derived cell line. We acquired EBV infected B cells whose growth was dependent on FDC derived cell line. Further studies about the roles of FDC in the reactivation of EBV are necessary.