[A case of rapidly progressive HTLV-I associated myelopathy that developed after a ‍living donor kidney transplantation].

Case Male in his 40s. Due to end-stage renal failure, a living donor kidney transplantation was performed in September 2019 from his mother, who was positive for anti-HTLV-1 antibodies, to this case, who was negative for anti-HTLV-1. He was admitted in September 2021 due to progressive lower limb muscle weakness since March 2021. The patient was unable to stand or walk due to spastic paraplegia. Spinal cord MRI T₂-weighted image showed continuous high signal and myelopathy from the cervical to thoracic spinal cord. Serum and spinal fluid anti-HTLV-1 antibodies were positive. The diagnosis of rapidly progressive HTLV-1-associated myelopathy (HAM) was made, which was problematic because kidney transplantation from an HTLV-1-positive donor to a negative recipient was performed in this case, even though it had already been noted that living donor-negative recipients are at high risk of developing HAM.