Fig. 4

The summarization and graphical representation of the strategy from diagnosis to treatment of ATL in renal transplant recipients according to the clinical guideline for PTLD after organ transplantation and the JSH Practical Guidelines for ATL. At present, although there is no established prevention and treatment for ATL or HAM after organ transplantation, based on the clinical guideline of PTLD after organ transplantation and the JSH Practical Guidelines for ATL, we performed the diagnosis and treatment of ATL after HTLV-1-positive organ transplantation. Thus, our experiences may be one of the crucial examples to assist ATL development in patients after renal transplantation in the future. The diagnosis of ATL is closely related to blood tests (HTLV-1 clonality by Southern blot analysis), tissue biopsy (immunohistochemical analysis), and radiological imaging (ATL staging). Regarding the treatment, the strategy of treatment is (i) to eliminate the ATL and (ii) to minimize the harm to transplanted organs. According to the clinical guidelines for PTLD after organ transplantation and the JSH Practical Guidelines for ATL, the withdrawal of immunosuppressive agents, including FK or CSP, is an essential treatment approach. Therefore, chemotherapy (a CHOP-like regimen) may be a subsequent therapeutic option. According to the response and organ dysfunction in recipient, the molecular-targeted therapy (CCR4 antibody, CD30 antibody, lenalidomide) or allo-HSCT may be treatment strategy for ATL after organ transplantation. Accumulation of ATL cases after organ transplantation is essential to establish a diagnosis and strategy for ATL after organ transplantation in the future. Regarding the prevention of HTLV-1 infection in endemic areas of HTLV-1 infection, such as our institution in Miyazaki Prefecture, we considered that suggested ways to prevent the development of ATL in renal transplant recipients may be the screening of HTLV-1 antibody. We did not perform organ transplantation from HTLV-1 carrier donors to HTLV-1- negative recipients in order to prevent HTLV-1 infection. In 2014, the Japanese Society for Clinical Renal Society and the Ministry of Health, Labour, and Welfare recommended the exclusion of HTLV-1-positive donors for renal transplantation. From the negative aspects of the view, case 3 (renal transplantation from HTLV-1-positive donor to HTLV-1-negative donor in another hospital and subsequent follow-up in our hospital case) showed the need for enlightenment regarding adherence to the guidelines in Japan. Thus, in endemic areas of HTLV-1 infection, to prevent new HTLV-1 infection, organ transplantation from HTLV-1 carrier donors to HTLV-1-negative recipients should be avoided in clinical practice