A COMPARISON OF EPIDEMIOLOGIC, HISTOLOGIC, AND VIROLOGICAL STUDIES ONHODGKINS-DISEASE IN WESTERN KENYA AND NAGASAKT, JAPAN

Rapid progress in molecular technologies has enabled the detection of several oncogenic viruses in various types of tumors. The pathogenesis of Hodgkin's disease is suggested to have a strong association with E pstein-Barr virus (EBV). However, Hodgkin's disease related to EBV sho ws a wide geographic variation in epidemiology. These variations among different populations suggest an interaction of environmental factors and a direct role of EBV infection. Therefore, we performed a compara tive study on epidemiologic, histologic, and virologic features of Hod gkin's disease among those in the western part of Kenya and in Nagasak i, Japan. The age distribution of Hodgkin's disease showed a distinct peak in the 0-9-year-old age group in Kenya, and a higher and lower pe ak in the 60-69- and 30-39-year-old age groups, respectively, in Japan . The most common subtype of Hodgkin's disease in both countries was m ixed cellularity, followed by nodular sclerosis, lymphocyte depletion, and lymphocyte predominance. Mixed cellularity showed a significantly high prevalence among Kenyan children nine years of age or younger. U sing the in situ hybridization method, EBV-encoded RNA (EBER-1) was de tected in 79% of the Kenyan cases and 59% of the Japanese cases, with the mixed cellularity subtype showing a strong correlation with EBER-1 . There was 100% positivity in both countries in those less than nine years old. These results suggest that EBV plays a more direct role in the pathogenesis of Hodgkin's diseases in Kenya, especially in cases a mong young children and also in Japanese children. Environmental and/o r genetic factors may have a role, in addition to EBV, in the pathogen esis of Hodgkin's disease, especially in Nagasaki, Japan.