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Characteristics of HAM/TSP after kidney transplantation from HTLV-1 positive living donors

It has been sporadically reported that HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP) develops after living-donor kidney transplantation from HTLV-1 positive donors (D+) to negative recipients (R-). However, these details have been unknown. Thus we evaluated the incidence and clinical characteristics of HAM/TSP after living-donor kidney transplantation from D+ to R-(D+R-transplantation). Using data obtained from the Japanese Renal Transplant Registry, we analyzed 13,299 cases of living-donor kidney transplantation between 2000 and 2013 in Japan. In addition, we have collected information about 5 patients who developed HAM/TSP after D+R-transplantation. The incidence of HAM/TSP after D+R-transplantation was calculated as the ratio of “the number of recipients who developed HAM/TSP” to “the number of cases of D+R-transplantation”. The characteristics of HAM/TSP in D+R-transplant recipients such as time from transplantation to disease onset and rate of disease progression are investigated. About 70% of all 13,299 donors took a HTLV-1 antibody test and 64 cases were positive for HTLV-1 antibody. Although the remaining 4,072 donors didn't take the antibody test, we estimated the number of HTLV-1 positive donors as 36 according to the HTLV-1 prevalence in Japan. As a result, the estimated incidence of HAM/TSP after D+R-transplantation was 5%. All the 5 cases of HAM/TSP after D+R-transplantation showed an early onset after transplantation. Four out of five cases developed rapidly and had difficulty walking in one or two years. This study demonstrated that incidence rate (5%) of HAM/TSP in recipients after D+R-transplantation is extremely higher compared to the lifetime risk (0.25%) of HAM/TSP in an HTLV-1-infected person. Further, this study suggested that HAM/TSP after D+R-transplantation is characterized by rapid onset and progression. Therefore, we need to conduct nationwide survey to assess the risk of D+R-transplantation.

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Correspondence to Miyuna Kimura.

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This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.

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Kimura, M., Yamauchi, J., Taisho, H. et al. Characteristics of HAM/TSP after kidney transplantation from HTLV-1 positive living donors. Retrovirology 12 (Suppl 1), O14 (2015).

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