title: Small number of HTLV-1-positive cells frequently remains during complete remission after allogeneic hematopoietic stem cell transplantation that are heterogeneous in origin among cases with adult T-cell leukemia/lymphoma.
abstract: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) can provide long-term remission for patients with adult T-cell leukemia/lymphoma (ATLL) caused by human retrovirus, human T-lymphocyte virus (HTLV-1). To understand how HTLV-1-positive cells including ATLL cells were suppressed by allo-HSCT, we examined HTLV-1 provirus load and residual ATLL cells in peripheral blood of transplant recipients using PCR-based tests. We found that the copy number of HTLV-1 genome, called provirus, became very small in number after allo-HSCT; however, in most cases, provirus did not disappear even among long-term survivors. Tumor-specific PCR tests demonstrated that most of HTLV-1-positive cells that remained long after transplantation were not primary ATLL cells but donor-derived HTLV-1-positive cells. We also found a case having very low amount of residual disease in peripheral blood even long after transplantation. There was only one recipient in whom we failed to show the presence of HTLV-1 genome and antibody against HTLV-1 even with an extensive search, which strongly suggested the elimination of HTLV-1 after allo-HSCT. These results demonstrated that after allo-HSCT the small amount of residual HTLV-1-positive cells were heterogeneous in origin and that long-term disease control for ATLL could be obtained without the complete elimination of HTLV-1.
authors.affiliation: Molecular Medicine Unit and Hematology, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Yamasaki
authors.forename: Y
authors.initials: Y
authors.lastname: Miyazaki
authors.forename: Y
authors.initials: Y
authors.lastname: Moriuchi
authors.forename: C
authors.initials: C
authors.lastname: Tsutsumi
authors.forename: T
authors.initials: T
authors.lastname: Fukushima
authors.forename: S
authors.initials: S
authors.lastname: Yoshida
authors.forename: J
authors.initials: J
authors.lastname: Taguchi
authors.forename: Y
authors.initials: Y
authors.lastname: Inoue
authors.forename: E
authors.initials: E
authors.lastname: Matsuo
authors.forename: Y
authors.initials: Y
authors.lastname: Imaizumi
authors.forename: D
authors.initials: D
authors.lastname: Imanishi
authors.forename: T
authors.initials: T
authors.lastname: Fujimoto
authors.forename: H
authors.initials: H
authors.lastname: Tsushima
authors.forename: S
authors.initials: S
authors.lastname: Honda
authors.forename: T
authors.initials: T
authors.lastname: Hata
authors.forename: K
authors.initials: K
authors.lastname: Tsukasaki
authors.forename: M
authors.initials: M
authors.lastname: Tomonaga
mesh_terms: D000328:Adult; D018380:Hematopoietic Stem Cell Transplantation; D015368:Human T-lymphotropic virus 1 / Q000302:isolation & purification*; D006801:Humans; D015459:Leukemia-Lymphoma, Adult T-Cell / Q000473:pathology / Q000628:therapy*; D016133:Polymerase Chain Reaction; D012074:Remission Induction; D014019:Tissue Donors; D014184:Transplantation, Homologous; D019562:Viral Load