ABSTRACT
Adult T-cell leukemia/lymphoma (ATL) is caused by human T-lymphotrophic virus type 1 infection and is one of the most refractory malignant T-cell lymphomas. Improvement of ATL therapy options requires the establishment of appropriate ATL animal models. In this study, we successfully generated an ATL mouse model by xenotransplantation of primary peripheral blood mononuclear cells (PBMCs) isolated from ATL patients (ATL cells) into nonobese diabetic/severe combined immunodeficiency/Jak3-null mice (NOJ mice). To generate the model, the ATL S1T cell line was subcutaneously injected into mice. Primary ATL cells were then transplanted subcutaneously, intraperitoneally, or intravenously. ATL cells infiltrated multiple organs, and elevated human soluble interleukin 2 receptor (IL-2R) levels were detected in peripheral blood. Injection of one million primary ATL cells was needed for successful engraftment into host mice. Thawed cells, frozen long-term in liquid nitrogen, could also be transplanted; however, more cells were required to achieve similar results. The median mouse survival time was proportional to the number of cells injected. Successful secondary transplantation of ATL cells from one NOJ mouse into another was achieved and confirmed by T-cell receptor analysis. Finally, we examined the effects of the antioxide pyrrolidine dithiocarbamate (PDTC) as an antitumor agent in vivo. PDTC administration inhibited the increase of soluble IL-2R and improved mouse survival, suggesting that this compound has potential as an anti-ATL agent. We demonstrated that ATL cells could be stably xenotransplanted into NOJ mice using primary cells. This model will be useful in the establishment of novel therapies to treat ATL.
Subject(s)
Antioxidants/pharmacology , Human T-lymphotropic virus 1 , Leukemia-Lymphoma, Adult T-Cell/drug therapy , Pyrrolidines/pharmacology , Thiocarbamates/pharmacology , Xenograft Model Antitumor Assays/methods , Adult , Animals , Heterografts , Humans , Leukemia-Lymphoma, Adult T-Cell/metabolism , Leukemia-Lymphoma, Adult T-Cell/pathology , Mice , Mice, Mutant Strains , Neoplasm Transplantation , Tumor Cells, CulturedABSTRACT
Adult T cell leukemia/lymphoma (ATL) is an aggressive peripheral T cell neoplasm with very poor prognosis. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) has been reported as a curative treatment modality for ATL. However, there are no reports comparing chemotherapy alone with allo-HSCT in ATL. In this report, we retrospectively analyzed data for patients treated with (n = 29, median age 55 years) or without allo-HSCT (n = 37, median age 58 years) for ATL in Kagoshima University Hospital, located in one of the most endemic areas of human T cell lymphotropic leukemia virus type 1 infection. Forty patients (61%) started coordination for allo-HSCT. Ten patients (34.4%) received allo-HSCT while in complete remission (CR), whereas the others were not in CR. Twenty-five patients (86.2%) received reduced-intensity conditioning, and the others received myeloablative conditioning. With a median follow-up period for survivors of 41 months (range, 5 to 125 months), the 3-year overall survival (OS) rate from first chemotherapy for all patients (with or without allo-HSCT) was 35.2%. The 3-year OS from first chemotherapy for patients who received allo-HSCT or only chemotherapy was 44.9% and 27.7%, respectively. Univariate analyses revealed that high serum soluble IL-2 receptor (sIL-2R) levels (≥ 2000 U/mL) just before the conditioning regimen and progressive disease (PD) status at HSCT (according to Japan Clinical Oncology Group Study 0907 criteria) were significant risk factors for OS in the allo-HSCT group. Multivariate analyses revealed that PD status was a significant risk factor for OS in the allo-HSCT group. In the chemotherapy-only group, the 3-year OS rate was 61.5% (95% CI, 30.8% to 81.8%) in patients with serum sIL-2R levels < 2000 U/mL for > 3 months. In contrast, the 3-year OS rate was 5.7% (95% CI, .4% to 22.4%) in patients who did not achieve serum sIL-2R levels < 2000 U/mL for >3 months. Our single-center cohort experience indicates that chemosensitivity is the most important prognostic factor for OS in ATL patients and the use of allo-HSCT is limited in chemorefractory patients with aggressive ATL disease. In the chemosensitive patients, allo-HSCT demonstrated a tendency toward better OS. Further clinical studies are warranted to determine optimal treatments for patients who are less sensitive to conventional chemotherapy.
