Wang Hx

Humanized anti-CD25 monoclonal antibody for prophylaxis of graft-vs-host disease (GVHD) in haploidentical bone marrow transplantation without ex vivo T-cell depletion

OBJECTIVE To investigate the effects of a novel anti-IL-2 receptor (CD25) monoclonal antibody, basiliximab, on graft-vs-host disease (GVHD) and engraftment in haploidentical bone marrow transplantation (BMT). MATERIALS AND METHODS Thirteen consecutive high-risk leukemia patients (age 9-41) underwent haploidentical BMT with G-CSF-primed marrow as stem cells without ex vivo T-cell depletion. Basiliximab, along with a combination of cyclosporine (CSA), methotrexate (MTX), and mycophenolate mofetil (MMF), was used for GVHD prophylaxis. Immunophenotyping, limited-dilution assay, and colony-forming assays were used to measure the effect of basiliximab on the subsets of lymphocytes, cytotoxic T-lymphocyte precursors (CTLp), and hematopoietic cells. RESULTS All patients established successful trilineage engraftment with full donor chimerism. No patients developed grade II-IV acute GVHD. Patients who survived more than 12 months and were free of relapse showed limited chronic skin GVHD. Ten of 13 patients are currently alive with a Karnofsky performance score of 100% at median follow-up of 17 months (range 12-24 months). Basiliximab significantly decreased alloreactive CTLp by 10-fold to 100-fold in limiting-dilution assays. It had no effect on hematopoietic stem and progenitor cells as determined by in vitro colony-forming assays. CONCLUSION The addition of basiliximab to CSA, MMF, and MTX as GVHD prophylaxis effectively reduced severe lethal GVHD in haploidentical BMT. It is possible to selectively eliminate or reduce the number of alloreactive T cells with anti-CD25 antibody, which results in prevention of or a reduction in the severity of GVHD.

HAPLOIDENTICAL HEMATOPOIETIC STEM CELL TRANSPLANTATION IN CHILD HEMATOLOGIC MALIGNANCIES WITH G-CSF-MOBILIZED MARROW GRAFTS WITHOUT T-CELL DEPLETION: A Single-Center Report of 45 Cases

In this report, the authors describe a protocol for haploidentical bone marrow transplantation in children who received G-CSF-mobilized bone marrow grafts without T-cell depletion from HLA-mismatched parents. Forty-two of 45 patients achieved complete donor hematopoietic engraftment; the medium time for neutrophil and platelet recovery was 17 and 19 days, respectively. Three died of early transplantation-associated complications; other causes of death included relapse (11 cases), fungal pneumonia (5), and acute graft-versus-host disease (2). The total disease-free survival rate longer than 2 years was 53.3%. These data suggest that haploidentical hematopoietic transplantation is an alterative strategy for children who lack immediate access to HLA-matched sources.

The epigenetically-regulated miR-34a targeting c-SRC suppresses RAF/MEK/ERK signaling pathway in K-562 cells

Previous reports show that miR-34a suppressed K-562 cell proliferation and contributed to megakaryocytic differentiation of K-562 cells. Here, we reported that miR-34a, a tumor suppressor gene, is down-regulated in the K-562 cells and chronic myeloid leukemia (CML) patients due to aberrant DNA hypermethylation. c-SRC is a target of miR-34a. Restoring miR-34a expression resulted in down-regulation of c-SRC and phosphorylated (Tyr416) c-SRC protein in K-562 cells, which consequently triggered suppression of the RAF/MEK/ERK signaling pathway to decrease cell proliferation.

The absolute number of regulatory T cells in unmanipulated peripheral blood grafts predicts the occurrence of acute graft-versus-host disease post haplo-identical hematopoietic stem cell transplantation

CD4+CD25+Foxp3+ regulatory T cells (Tregs) have been reported to play a central role in suppressing acute graft-versus-host disease (aGVHD), but whether the Treg contents of grafts correlates with the occurrence of aGVHD post haplo-identical hematopoietic stem cell transplantation (haplo-HSCT) remains unclear. In the present study, changes in Tregs in peripheral blood (PB) were followed before and after granulocyte colony-stimulating factor (G-CSF) mobilization. In addition, functional analyses of Tregs in PB grafts and bone marrow (BM) grafts were performed. To probe the prognostic value of Tregs for aGVHD, an analysis of Tregs in haplo-identical grafts was conducted in 61 patients. Moreover, univariate and multivariate analyses of both clinical variables and cellular subsets were performed. The results showed that both the percentage Tregs of CD4+ T cells and absolute numbers of Tregs per 106 total nucleated cells significantly increased after G-CSF administration. Additionally, Tregs in PB grafts exhibited a stronger inhibitory effect on antigen-specific T cell proliferation than did Tregs in BM grafts. Strikingly, patients receiving more Tregs in PB grafts had a lower cumulative incidence of aGVHD II-IV (36% versus 58%, P=0.046). Further, in a multivariate analysis, the number of Tregs in PB grafts was significantly associated with a lower occurrence of aGVHD II-IV (P=0.02). In contrast, the number of Tregs in BM grafts was not associated with the occurrence of aGVHD in the current study. Further analysis showed that the Treg content in grafts did not affect Treg reconstitution, infection rate, or incidence of chronic GVHD after haplo-HSCT. Moreover, no significant correlations between cell types in grafts and the survival end points or relapse rates were found in the present study. In conclusion, our results suggest that a high number of Tregs in PB grafts is associated with reduced risk of aGVHD in haplo-HSCT in our transplant setting.

Mesenchymal Stem Cells in Grafts Failed to Engraft in the Bone Marrow Microenvironment of a Leukemia Patient Post HLA-match and Haplo-Identical Allogeneic Hematopoietic Stem cell Transplantations

Mesenchymal stem cells (MSCs) are an important cellular component of the bone marrow microenvironment (BM-ME) [1–3]. After hematopoietic stem cell transplantation (HSCT), the normal rebuilding of the recipient’s BM-ME is vital for the reconstitution of the immune system and hematopoiesis. However, it remains controversial whether donor MSCs in grafts can aid in the rebuilding of the patient’s BM-ME [4,5]. Here, we report a unique case that the BM-MSCs from a patient who received tandem HSCTs remain host-origin. A 17-year-old male with chronic myeloid leukemia was admitted to our hospital 5 years after receiving human leukocyte antigen (HLA)matched peripheral blood stem cell (PBSC) transplantation because he was experiencing a relapse of his primary disease. The HLA-matched grafts were from his brother, and the pre-conditioning regimen was myeloablative, consisting of busulfan and cyclophosphamide. In our hospital, he was treated with a Hyper-CVMD A and B chemotherapy regimen combined with nilotinib, and the treatment resulted in complete remission. Then, he received a haplo-identical HSCT with a myeloablative pre-conditioning regimen consisting of busulfan (12 mg/kg), cyclophosphamide (110 mg/kg), and cytarabine (8 g/m2). The haplo-identical grafts included PBSCs (8 × 108/kg of nucleated cells) and BM cells (2.72 × 108 /kg of nucleated cells) from his mother. The transplantation was successful, and the chimerism was analyzed using short-tandem repeats (STR). The