Transmission of Human T-Lymphotropic Virus Type I to Donor-Origin T Cells During Allogeneic Hematopoietic Stem Cell Transplantation

Human T-lymphotropic virus type I (HTLV-I) is a retrovirus that causes adult T-cell leukemia/lymphoma (ATLL), an aggressive CD4-positive mature T-cell malignancy with a dismal prognosis [1, 2]. In addition, the virus is associated with chronic inflammatory diseases such as HTLV-I-associated myuveitis, dermatitis, and bronchioloalveolar disorders. It is estimated that HTLV-I infects 5 - 20 million individuals worldwide [3, 4]. HTLV-I is transmitted via breast feeding, sexual intercourse, needle sharing, and blood products containing cells. Organ transplantation has also been considered a rare route of HTLV-I transmission [5]. Here, we describe a case of HTLV-I transmission to T cells of an HTLV-I-negative donor through allogeneic hematopoietic stem cell transplantation (allo-HSCT). A 56-year-old man with a history of ATLL was referred to our hospital for dyspnea. Two years before the presentation, he underwent allogeneic peripheral blood stem cell transplantation (allo-PBSCT) from an HTLV-I-negative female donor with a reduced in