scholarly journals Human proT-cells generated in vitro facilitate hematopoietic stem cell-derived T-lymphopoiesis in vivo and restore thymic architecture

Blood ◽  
2013 ◽  
Vol 122 (26) ◽  
pp. 4210-4219 ◽  
Author(s):  
Génève Awong ◽  
Jastaranpreet Singh ◽  
Mahmood Mohtashami ◽  
Maria Malm ◽  
Ross N. La Motte-Mohs ◽  
...  

Key Points Intrathymic T-cell regeneration is facilitated by human proT-cells generated in vitro. In vitro–generated human proT-cells home to the thymus, wherein they restore thymic structure.

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 839-839 ◽  
Author(s):  
Xiao Jun Huang

Abstract 839FN2 Many patients who require allogeneic hematopoietic stem cell transplantation (allo-HSCT) lack a human leukocyte antigen (HLA)-matched donor. Recently, we developed a new strategy named GIAC protocol for HLA-mismatched/haploidentical transplantation from family donors that combines granulocyte-colony stimulating factor (G-CSF) primed bone marrow (G-BM) and peripheral blood stem cells (PBSC) without in vitro T-cell depletion (TCD). For the past nine years, promising results for HLA-mismatched allo-HSCT without in vitro TCD have been achieved at our institute using this protocol. From May 2002 to December 2010, 820 patients, including 206 in high-risk group, underwent transplantation from haploidentical family donors. Eight-hundred and eleven patients (99%) achieved sustained, full donor chimerism. The incidence of grade 2–4 acute graft-versus-host disease (GVHD) was 42.9%, and that of grades 3 and 4 was 14.0% which was not associated with the extent of HLA disparity.Figure 1Cumulative incidence of acute GVHD grade 2–4 according to HLA disparity.Figure 1. Cumulative incidence of acute GVHD grade 2–4 according to HLA disparity.Figure 2Probability of LFS after haploidentical HSCT according to disease stage (p =.001).Figure 2. Probability of LFS after haploidentical HSCT according to disease stage (p =.001). Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 455-455
Author(s):  
Jaebok Choi ◽  
Edward Dela Ziga ◽  
Julie Ritchey ◽  
Lynne Collins ◽  
Julie Prior ◽  
...  

Abstract Abstract 455 Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is the only curative treatment for patients with relapsed/refractory leukemia, and marrow failure states such as myelodysplasia and aplastic anemia. However, allo-HSCT is complicated by allogeneic donor T cell-mediated graft-versus-host disease (GvHD) which can be life-threatening especially in recipients of unrelated or HLA-mismatched hematopoietic stem cell products. These same alloreactive donor T cells also mediate a beneficial graft-versus-leukemia (GvL) effect. Thus, the clinical goal in allo-HSCT is to minimize GvHD while maintaining GvL. Recent studies have suggested that this might be achieved by infusing regulatory T cells (Tregs) which in some preclinical models suppress GvHD-causing alloreactive donor T cells but have only limited effects on GvL-promoting alloreactive donor T cells. Unfortunately, Tregs exist in low frequency in the peripheral blood, are costly to purify and expand, and after expansion are difficult to isolate due to the lack of cell surface markers, all of which prevent their routine use in the clinic. Thus, alternative therapeutic approaches that do not require Tregs are needed. We have found that interferon gamma receptor deficient (IFNγR−/−) allogeneic donor T cells induce significantly less GvHD in both a MHC fully-mismatched (B6 (H-2b) → Balb/c (H-2d)) and a minor-mismatched (B6 (H-2b) → B6×129(H-2b)) allo-HSCT models compared to WT T cells. In addition, IFNγR−/− donor T cells maintain a beneficial GvL effect, which has been examined in both systemic leukemia and solid tumor models using luciferase-expressing A20 cells derived from Balb/c. We find that IFNγR−/− T cells migrate primarily to the spleen while WT T cells to GI tract and peripheral lymph nodes (LNs) using bioluminescence imaging (BLI), suggesting that altered T cell trafficking of IFNγR−/− T cells to GvHD target organs might be the major reason for the reduced GvHD. We further demonstrate that the IFNγR-mediated signaling in alloreactive donor T cells is required for expression of CXCR3 which has been implicated in trafficking of T cells to areas of inflammation and target organs, commonly known to be the sites of GvHD. Indeed, CXCR3−/− T cells recapitulate the reduced GvHD potential of IFNγR−/− T cells. In addition, forced overexpression of CXCR3 in IFNγR−/− T cells via retroviral transduction partially rescues the GvHD defect observed in IFNγR−/− T cells. We next examine if inhibition of IFNγR signaling using a small molecule inhibitor can recapitulate the anti-GVHD effects seen in IFNγR−/− T cells. We find that INCB018424, an inhibitor of JAK1/JAK2 which are the mediators of IFNγR signaling, blocks CXCR3 expression in vitro. Most importantly, in vivo administration of INCB018424 after allo-HSCT alters T cell trafficking and significantly reduces GvHD. Thus, the IFNγR signaling pathway represents a promising therapeutic target for future efforts to mitigate GvHD while maintaining GvL after allo-HSCT. Moreover, this pathway can be exploited in other diseases besides GvHD such as those from organ transplantation, chronic inflammatory diseases and autoimmune diseases. Disclosures: DiPersio: genzyme: Honoraria.


Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 3115-3115
Author(s):  
Scott R. Solomon ◽  
Melissa Sanacore ◽  
Xu Zhang ◽  
Katelin Connor ◽  
Melhem Solh ◽  
...  

Abstract In vivo T Cell Depletion with Thymoglobulin or Alemtuzumab Is Associated With Worse Outcome Following Allogeneic Hematopoietic Stem Cell Transplantation for Acute Myeloid Leukemia Patients Transplanted in Remission. Allogeneic hematopoietic stem cell transplantation (HSCT) reduces relapse risk in adults with acute myeloid leukemia (AML) due in large part to the potent graft-versus-leukemia effect of donor lymphocytes. However, this benefit must be balanced by the increased morbidity and mortality associated with graft-versus-host disease (GVHD). Serotherapy, in the form of thymoglobulin or alemtuzumab, has been used for in vivo T cell depletion as a strategy to reduce GVHD. We analyzed 144 consecutive AML patients transplanted in remission (CR1 - 111, CR≥2 - 33) from either a matched related (MRD, n=44), unrelated (MUD, n=62), or haploidentical (haplo, n=38) marrow of PBSC donor, in order to analyze the effect of serotherapy, in relation to other disease-, patient- and transplant-related risk factors, on post-transplant outcomes. Patients were transplanted at a single institution between 3/15/06 to 12/19/14. Baseline characteristics of the patient cohort included age >50 in 88 (61%), KPS<90 in 93 (65%), CMI ≥3 in 61 (42%) of patients. Disease risk index (DRI) was defined as low, intermediate, and high in 5 (4%), 110 (76%), and 29 (20%) patients respectively per the revised Dana Farber/CIBMTR criteria. Myeloablative chemotherapy was given in 96 (67%) patients, and PBSC was the source of stem cells in 120 (83%) patients. Serotherapy was utilized in 21 (15%) patients [thymoglobulin - 8, alemtuzumab - 13]. Serotherapy patients were more likely to be older (median age 59 vs. 52 years, p=0.013) and have a MUD (81% vs. 37%, p<0.001), but otherwise had similar baseline characteristics in regards to disease status, DRI, regimen intensity. Acute GVHD grade II-IV occurred in 38% of patients, whereas chronic GVHD was seen in 44%. Chronic GVHD occurred less often in patients receiving serotherapy (19% vs. 49%, p=0.016). Estimated one year non-relapse mortality (NRM) at 1 and 3 years was 4% and 13% respectively and was statistically similar in serotherapy and non-serotherapy patients. The estimated 3 year OS, DFS, and relapse was 58%, 51%, and 37% respectively for the whole cohort; 64%, 55%, and 33% in non-serotherapy patients vs. 29%, 27%, and 57% in serotherapy patients (figure 1). Cox analysis was performed utilizing the following variables: age, disease status, DRI, KPS, CMI, transplant type (MRD, MUD, haplo), conditioning intensity, stem cell source, use of serotherapy, year of transplant, acute and chronic GVHD. Variables were selected by a 10% threshold. Acute and chronic GVHD were modeled as time-dependent variables. In multivariate analysis, unfavorable risk factors for survival included only two variables: the use of serotherapy (HR 3.11, p<0.001) and high risk DRI (HR 1.89, p=0.038). Use of serotherapy also had a negative effect on relapse (HR 2.69, p=0.003) and DFS (HR 2.73, p<0.001), with no effect on NRM. Following allogeneic HSCT for AML patients in remission, the use of serotherapy for in vivo T cell depletion had a major negative impact on survival due to increased relapse risk. Figure 1. Figure 1. Disclosures No relevant conflicts of interest to declare.


Author(s):  
Steven Strubbe ◽  
Tom Taghon

Hematopoietic stem cells (HSCs) reside in distinct sites throughout fetal and adult life and give rise to all cells of the hematopoietic system. Because of their multipotency, HSCs are capable of curing a wide variety of blood disorders through hematopoietic stem cell transplantation (HSCT). However, due to HSC heterogeneity, site-specific ontogeny and current limitations in generating and expanding HSCs in vitro, their broad use in clinical practice remains challenging. To assess HSC multipotency, evaluation of their capacity to generate T lymphocytes has been regarded as a valid read-out. Several in vitro models of T cell development have been established which are able to induce T-lineage differentiation from different hematopoietic precursors, although with variable efficiency. Here, we review the potential of human HSCs from various sources to generate T-lineage cells using these different models in order to address the use of both HSCs and T cell precursors in the clinic.


Blood ◽  
1995 ◽  
Vol 85 (4) ◽  
pp. 952-962 ◽  
Author(s):  
JC van der Loo ◽  
WA Slieker ◽  
D Kieboom ◽  
RE Ploemacher

Monoclonal antibody ER-MP12 defines a novel antigen on murine hematopoietic stem cells. The antigen is differentially expressed by different subsets in the hematopoietic stem cell compartment and enables a physical separation of primitive long-term repopulating stem cells from more mature multilineage progenitors. When used in two-color immunofluorescence with ER-MP20 (anti-Ly-6C), six subpopulations of bone marrow (BM) cells could be identified. These subsets were isolated using magnetic and fluorescence-activated cell sorting, phenotypically analyzed, and tested in vitro for cobblestone area-forming cells (CAFC) and colony-forming units in culture (CFU-C; M/G/E/Meg/Mast). In addition, they were tested in vivo for day-12 spleen colony-forming units (CFU-S-12), and for cells with long-term repopulating ability using a recently developed alpha-thalassemic chimeric mouse model. Cells with long-term repopulation ability (LTRA) and day-12 spleen colony-forming ability appeared to be exclusively present in the two subpopulations that expressed the ER-MP12 cell surface antigen at either an intermediate or high level, but lacked the expression of Ly- 6C. The ER-MP12med20- subpopulation (comprising 30% of the BM cells, including all lymphocytes) contained 90% to 95% of the LTRA cells and immature day-28 CAFC (CAFC-28), 75% of the CFU-S-12, and very low numbers of CFU-C. In contrast, the ER-MP12hi20- population (comprising 1% to 2% of the BM cells, containing no mature cells) included 80% of the early and less primitive CAFC (CAFC-5), 25% of the CFU-S-12, and only 10% of the LTRA cells and immature CAFC-28. The ER-MP12hi cells, irrespective of the ER-MP20 antigen expression, included 80% to 90% of the CFU-C (day 4 through day 14), of which 70% were ER-MP20- and 10% to 20% ER-MP20med/hi. In addition, erythroblasts, granulocytes, lymphocytes, and monocytes could almost be fully separated on the basis of ER-MP12 and ER-MP20 antigen expression. Functionally, the presence of ER-MP12 in a long-term BM culture did not affect hematopoiesis, as was measured in the CAFC assay. Our data demonstrate that the ER-MP12 antigen is intermediately expressed on the long-term repopulating hematopoietic stem cell. Its level of expression increases on maturation towards CFU-C, to disappear from mature hematopoietic cells, except from B and T lymphocytes.


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