Pathological study on nasal T-cell lymphoma in East Asia

鼻t细胞淋巴瘤（NTL）是临床上表现为致死性中线肉芽肿的疾病之一。在组织学上，NTL表现为细胞增殖的多态模式，因此也被称为多态网状病（PR）。我们之前的研究显示，日本除冲绳外每10万名就诊耳鼻喉门诊患者的NTL发病率为8.0，冲绳为27.4，韩国首尔为40.8，中国上海为9.8，均高于英国。最近的研究表明eb病毒（EBV）在NTL发病中的病原学作用。本研究探讨了NTL发病率与增殖细胞中EBV阳性频率的相关性。为此，我们选择冲绳（20例）和大阪（32例）的鼻腔淋巴瘤进行组织学和免疫组织化学研究。采用PCR和原位法检测EBV的存在。免疫组化结果：B细胞型27例（大阪20例，冲绳7例），T细胞型20例（大阪9例，冲绳11例），未知5例。大阪地区鼻腔B细胞淋巴瘤15例中有6例（40%）和5例中有4例（80%）检测到EBV基因组，冲绳地区7例中有3例（43%）和7例中有7例（100%）检测到EBV基因组。这些发现提示EBV可能在日本的鼻鼻淋巴瘤中不仅是T细胞型，而且是B细胞型的致病因素。同时，冲绳的NTL发病率高于大阪，不能用肿瘤中EBV的阳性比例不同来解释。其他因素，如环境或生活方式对NTL的发展可能很重要。

Nasal T-cell lymphoma (NTL) is one of diseases clinically showing lethal midline granuloma. Histologically NTL shows polymorphous pattern of cellular proliferation, thus also having been called as polymorphic reticulosis (PR). Our previous study showed the incidence rate of NTL per 100, 000 patients visiting Ear-Nose-Throat Clinic was 8.0 in Japan other than Okinawa, 27.4 in Okinawa, 40.8 in Seoul (Korea), and 9.8 in Shanghai (China), which were higher than that in England. Recent study suggested the etiological role of Epstein-Barr virus (EBV) for development of NTL.In the current study, correlation between the incidence rate of NTL and frequency of EBV positivity in the proliferating cells was examined. For this purpose, nasal lymphoma in Okinawa (20 cases) and Osaka (32 cases) were selected for histologic and immunohistochemical studies. Presence of EBV was examined by the PCR and in situ methods.Immunohistochemically, 27 cases were B cell type (20 Osaka, 7 Okinawa), 20 were T cell type (9 Osaka, 11 Okinawa), and 5 were undefined. EBV genome was found in 6 of 15 cases (40%) and 4 of 5 cases (80%) of nasal B and T cell lymphomas in Osaka and 3 of 7 cases (43%) and 7 of 7 cases (100%) in Okinawa, showing the different frequencies of positivity by immunophenotype but not by district. These findings suggest that EBV might be a causative factor in sino-nasal lymphoma of not only T cell but also B cell type in Japan. Meanwhile the higher incidence of NTL in Okinawa than in Osaka could not be explained by the different positivity ratio of EBV in the tumors. Other factors such as environmetal or life style on the development of NTL might be important.