Mei Guo

Infusion of HLA-mismatched peripheral blood stem cells improves the outcome of chemotherapy for acute myeloid leukemia in elderly patients

Treatment outcome of acute myeloid leukemia (AML) in elderly patients remains unsatisfactory. It has been shown that the infusion of granulocyte colony-stimulating factor-mobilized donor peripheral blood stem cells (G-PBSCs) can enhance graft-versus-leukemia effects and speed hematopoietic recovery. Fifty-eight AML patients aged 60-88 years were randomly assigned to receive induction chemotherapy with cytarabine and mitoxantrone (control group; n = 28) or it plus human leukocyte antigen-mismatched G-PBSCs (G-PBSC group; n = 30). Patients who achieved complete remission received another 2 cycles of postremission therapy with intermediate-dose cytarabine or it plus G-PBSCs. The complete remission rate was significantly higher in the G-PBSC group than in the control group (80.0% vs 42.8%; P = .006). The median recovery times of neutrophils and platelets were 11 days and 14.5 days, respectively, in the G-PBSC group and 16 days and 20 days, respectively, in the control group after chemotherapy. The 2-year probability of disease-free survival was significantly higher in the G-PBSC group than in the control group (38.9% vs 10.0%; P = .01). No graft-versus-host disease was observed in any patient. Persistent donor microchimerism was successfully detected in all of the 4 female patients. These results indicate that G-PBSCs in combination with conventional chemotherapy may provide a promising treatment method for AML in elderly patients.

A Modified Haploidentical Nonmyeloablative Transplantation without T Cell Depletion for High-Risk Acute Leukemia: Successful Engraftment and Mild GVHD

Severe graft-versus-host disease (GVHD) and graft rejection still remain major complications of haploidentical nonmyeloablative (NMA) stem cell transplantation. Recent studies have shown that bone marrow-derived mesenchymal stem cells (MSCs) possess immunomodulatory capacity and may promote hematopoietic engraftment. The purpose of this study was to observe if the new strategy, which included a haploidentical peripheral blood stem cell transplantation (PBSCT) combined with MSCs, modified NMA conditioning, and GVHD prophylaxis would improve donor engraftment and prevent severe GVHD. The modified conditioning approach consisted of fludarabine (Flu), low-dose total body irradiation (TBI), cyclophosphamide (Cy), cytarabine, and anti-Tcell-lymphocyte globulin, whereas the GVHD prophylaxis consisted of cyclosporin A (CsA), mycophenolate mofetil (MMF), anti-CD25 antibody and intrabone marrow injection of MSCs. Thirty-three patients with high-risk acute leukemia underwent transplantation with PBSC from HLA-haploidentical donors without T cell depletion. All of the patients achieved full donor chimerisms, including 6 who switched to full donor chimerisms from mixed chimerisms in 1 to 2 months after the transplantations. Rapid hematological engraftment was observed with neutrophils >0.5 x 10(9)/L at day 11 and platelets >20 x 10(9)/L at day 14. Fifteen patients (45.5%) developed grade I-IV acute GVHD (aGVHD) and only 2 (6.1%) developed grade III to IV aGVHD. Nine (31%) of 29 evaluable patients experienced chronic GVHD (cGVHD). Upon follow-up for 1.5 to 60 months, 20 (60.6%) patients were alive and well and 6 (18.2%) had relapsed leukemia in the 33 patients. The probability of 3-year survival was 57.2%. The results indicate that this new strategy is effective in improving donor engraftment and preventing severe GVHD, which will provide a feasible option for the therapy of high-risk acute leukemia.

HLA-Mismatched Stem-Cell Microtransplantation As Postremission Therapy for Acute Myeloid Leukemia: Long-Term Follow-Up

PURPOSE Despite best current therapies, approximately half of patients with acute myeloid leukemia in first complete remission (AML-CR1) with no HLA-identical donors experience relapse. Whether HLA-mismatched stem-cell microtransplantation as a novel postremission therapy in these patients will improve survival and avoid graft-versus-host disease (GVHD) is still unknown. PATIENTS AND METHODS One hundred one patients with AML-CR1 (9 to 65 years old) from four treatment centers received programmed infusions of G-CSF-mobilized HLA-mismatched donor peripheral-blood stem cells after each of three cycles of high-dose cytarabine conditioning without GVHD prophylaxis. Donor chimerism and microchimerism and WT1+CD8+ T cells were analyzed. RESULTS The 6-year leukemia-free survival (LFS) and overall survival (OS) rates were 84.4% and 89.5%, respectively, in the low-risk group, which were similar to the rates in the intermediate-risk group (59.2% and 65.2%, respectively; P=.272 and P=.308). The 6-year LFS and OS were 76.4% and 82.1%, respectively, in patients who received a high dose of donor CD3+ T cells (≥1.1×10(8)/kg) in each infusion, which were significantly higher than the LFS and OS in patients who received a lower dose (<1.1×10(8)/kg) of donor CD3+ T cells (49.5% and 55.3%, respectively; P=.091 and P=.041). No GVHD was observed in any of the patients. Donor microchimerism (2 to 1,020 days) was detected in 20 of the 23 female patients who were available for Y chromosome analysis. A significant increase in WT1+CD8+ T cells (from 0.2% to 4.56%) was observed in 33 of 39 patients with positive HLA-A*02:01 antigen by a pentamer analysis. CONCLUSION Microtransplantation as a postremission therapy may improve outcomes and avoid GVHD in patients with AML-CR1.

Co-infusion of haplo-identical CD19-chimeric antigen receptor T cells and stem cells achieved full donor engraftment in refractory acute lymphoblastic leukemia

BackgroundElderly patients with relapsed and refractory acute lymphoblastic leukemia (ALL) have poor prognosis. Autologous CD19 chimeric antigen receptor-modified T (CAR-T) cells have potentials to cure patients with B cell ALL; however, safety and efficacy of allogeneic CD19 CAR-T cells are still undetermined.Case presentationWe treated a 71-year-old female with relapsed and refractory ALL who received co-infusion of haplo-identical donor-derived CD19-directed CAR-T cells and mobilized peripheral blood stem cells (PBSC) following induction chemotherapy. Undetectable minimal residual disease by flow cytometry was achieved, and full donor cell engraftment was established. The transient release of cytokines and mild fever were detected. Significantly elevated serum lactate dehydrogenase, alanine transaminase, bilirubin and glutamic-oxalacetic transaminase were observed from days 14 to 18, all of which were reversible after immunosuppressive therapy.ConclusionsOur preliminary results suggest that co-infusion of haplo-identical donor-derived CAR-T cells and mobilized PBSCs may induce full donor engraftment in relapsed and refractory ALL including elderly patients, but complications related to donor cell infusions should still be cautioned.Trial registrationAllogeneic CART-19 for Elderly Relapsed/Refractory CD19+ ALL. NCT02799550

Estimation of the biological dose received by five victims of a radiation accident using three different cytogenetic tools

The present study aims to estimate the biological doses received by five victims (A, B, C, D and E) of the Shanxi Taiyuan radiation accident in China of 2008 and to investigate the value of the cytokinesis-block micronuclei (CBMN) and premature chromosome condensation (PCC) assays in the estimation of biological doses received by the victims of a radiation accident. Conventional chromosome aberration analysis and the CBMN assay, as well as a drug-induced PCC assay recently established by our group, were performed on peripheral blood and bone marrow samples from five victims after the accident. The biological doses were estimated by scoring dicentrics plus centric rings, micronuclei and PCC rings. A high dose-effect curve and the nuclear division index (NDI) we previously established were used to estimate the dose received by victim A, the most highly affected victim of the five. The doses for the five victims (A, B, C, D and E) were 12.4, 3.4, 2.5, 2.1 and 2.2Gy, respectively, estimated by scoring dicentrics plus rings in peripheral blood lymphocytes. Similar results were obtained by combining the CBMN and NDI (CBMN+NDI) assays and the PCC assay. The doses estimated by the three methods were in accordance with the clinical symptoms observed. The specific dicentric assay with a low background level may be a better indicator for biological dose evaluation than the CBMN and PCC assays. The high dose curve we established is reliable and could become a suitable supplement to traditional biodosimetry for dose estimation. The CBMN and drug-induced PCC assays are simple, rapid and accurate. The two methods reinforce and verify the results observed with chromosome aberration analysis.

Severe acute radiation syndrome: treatment of a lethally 60Co-source irradiated accident victim in China with HLA-mismatched peripheral blood stem cell transplantation and mesenchymal stem cells.

This is a case report of a 32-year-old man exposed to a total body dose of 14.5 Gy γ-radiation in a lethal 60Co-source irradiation accident in 2008 in China. Frequent nausea, vomiting and marked neutropenia and lymphopenia were observed from 30 min to 45 h after exposure. HLA-mismatched peripheral blood stem cell transplantation combined with infusion of mesenchymal stem cells was used at Day 7. Rapid hematopoietic recovery, stable donor engraftment and healing of radioactive skin ulceration were achieved during Days 18–36. The patient finally developed intestinal obstruction and died of multi-organ failure on Day 62, although intestinal obstruction was successfully released by emergency bowel resection.

HLA-Mismatched Microtransplant in Older Patients Newly Diagnosed With Acute Myeloid Leukemia: Results From the Microtransplantation Interest Group

Importance The outcome of older patients with acute myeloid leukemia (AML) remains unsatisfactory. Recent studies have shown that HLA-mismatched microtransplant could improve outcomes in such patients. Objective To evaluate outcomes in different age groups among older patients with newly diagnosed AML who receive HLA-mismatched microtransplant. Design, Setting, and Participants This multicenter clinical study included 185 patients with de novo AML at 12 centers in China, the United States, and Spain in the Microtransplantation Interest Group. Patients were divided into the following 4 age groups: 60 to 64 years, 65 to 69 years, 70 to 74 years, and 75 to 85 years. The study period was May 1, 2006, to July 31, 2015. Exposures Induction chemotherapy and postremission therapy with cytarabine hydrochloride with or without anthracycline, followed by highly HLA-mismatched related or fully mismatched unrelated donor cell infusion. No graft-vs-host disease prophylaxis was used. Main Outcomes and Measures The primary end point of the study was to evaluate the complete remission rates, leukemia-free survival, and overall survival in different age groups. Additional end points of the study included hematopoietic recovery, graft-vs-host disease, relapse rate, nonrelapse mortality, and other treatment-related toxicities. Results Among 185 patients, the median age was 67 years (range, 60-85 years), and 75 (40.5%) were female. The denominators in adjusted percentages in overall survival, leukemia-free survival, relapse, and nonrelapse mortality are not the sample proportions of observations. The overall complete remission rate was not significantly different among the 4 age groups (75.4% [52 of 69], 70.2% [33 of 47], 79.1% [34 of 43], and 73.1% [19 of 26). The 1-year overall survival rates were 87.7%, 85.8%, and 77.8% in the first 3 age groups, which were much higher than the rate in the fourth age group (51.7%) (P = .004, P = .008, and P = .04, respectively). The 2-year overall survival rates were 63.7% and 66.8% in the first 2 age groups, which were higher than the rates in the last 2 age groups (34.2% and 14.8%) (P = .02, P = .03, P < .001, and P < .001, respectively). The 1-year cumulative incidences of nonrelapse mortality were 10.2%, 0%, 3.4%, and 26.0% in the 4 age groups and 8.1% in all patients. The median times to neutrophil and platelet recovery were 12 days and 14 days after induction chemotherapy, respectively. Five patients had full or mixed donor engraftment, and 30.8% (8 of 26) of patients demonstrated donor microchimerism. Two patients (1.1%) developed severe acute graft-vs-host disease. Conclusions and Relevance Microtransplant achieved a high complete remission rate in AML patients aged 60 to 85 years and higher 1-year overall survival in those aged 60 to 74 years.

A Study of Human Leukocyte Antigen Mismatched Cellular Therapy (Stem Cell Microtransplantation) in High-Risk Myelodysplastic Syndrome or Transformed Acute Myelogenous Leukemia

The treatment outcomes of myelodysplastic syndrome (MDS) and transformed acute myelogenous leukemia (tAML) remain very unsatisfactory. We designed a combination of human leukocyte antigen (HLA)‐mismatched hematopoietic stem cell microtransplantation (MST) with chemotherapy for patients with MDS and tAML and evaluated its effects and toxicity. Patients were between 13 and 79 years old. Patients with MDS (n = 21) were given HLA‐mismatched MST combined with decitabine and cytarabine; patients with tAML (n = 22) were given HLA‐mismatched MST combined with decitabine and cytarabine, and also mitoxantrone. Patients in complete remission (CR) also received MST plus decitabine and medium‐dose cytarabine chemotherapy without graft‐versus‐host disease (GVHD) prophylaxis. The overall response rate of the patients with MDS was significantly higher than that of those with tAML (81% vs. 50%; p = .03). The CR rates were 52.4% and 36.4% in the two groups, respectively. There was no difference in the cytogenetic CR rate between the MDS and tAML groups (85.7% vs. 70%, respectively; p = .7). The 24‐month overall survival of the patients with MDS was significantly higher than that of the patients with tAML (84.7% and 34.1%, respectively; p = .003). The median recovery times of neutrophils and platelets were, respectively, 14 and 17 days in the patients with MDS, and 16 and 19 days in those with tAML. The treatment‐related mortality rates were 4.8% and 18.2%, respectively, in the MDS and tAML groups (p = .34). No GVHD was observed in any patient. Microtransplantation combined with decitabine and chemotherapy may provide a novel, effective, and safe treatment for high‐risk MDS and tAML.

Effects of recombinant human granulocyte colony-stimulating factor on central and peripheral T lymphocyte reconstitution after sublethal irradiation in mice

Granulocyte colony-stimulating factor (G-CSF) is one of the most critical cytokines used for the treatment of acute radiation syndrome (ARS). In addition to the hematopoietic effects of G-CSF on the differentiation and proliferation of myeloid progenitor cells, G-CSF is also known to have immunomodulatory effects. The aim of the present study was to investigate whether G-CSF could accelerate central and peripheral T lymphocyte recovery after a sublethal dose of irradiation. Female BALB/c mice were subjected to 6 Gy of total body irradiation and then were treated with either 100 μg/kg G-CSF or an equal volume of PBS once daily for 14 days. Percentages of thymocyte subpopulations including CD4 − CD8 − , CD4 + CD8 + , CD4 + CD8− and CD4 − CD8+ T cells, peripheral CD3 + , CD4+ and CD8+ cells were analyzed by flow cytometry. Recent thymic emigrants (RTEs) were assessed by real-time polymerase chain reaction (PCR) using primers specific to the 257-bp T cell receptor rearrangement excision circles (sjTRECs). The proliferative capacity of splenic mononuclear cells upon exposure to ConA was measured by using the Cell Count Kit-8 (CCK-8). G-CSF treatment promoted thymocyte regeneration, accelerated the recovery of CD4 + CD8+ cells and increased the frequency of thymocyte sjTRECs. These effects were more prominent at early time points (Day 28) after irradiation. G-CSF also increased the rate of recovery of peripheral CD3 + , CD4+ and CD8+ cells and shortened the period of severe lymphopenia following irradiation. G-CSF also increased the splenic mononuclear cell mitotic responsiveness to ConA more than control-treated cells. Our results show that G-CSF accelerates T cell recovery through both thymic-dependent and thymic-independent pathways, which could be used to increase the rate of immune reconstitution after sublethal irradiation.

The existence and role of microchimerism after microtransplantion

AIM To study microchimerisms role and function after microtransplantation and identify novel genetic markers for microchimerism detection. METHODS Analyzing microchimerisms from patients microtransplanted to determine the presence of GSTT1, GSTM1, SRY and other genetic markers by real-time PCR. RESULTS Microchimerism could be detected for a short time after microtransplantation simultaneously with hematopoietic recovery. In conclusion, microchimerism might accelerate hematopoietic recovery and GSTT1 and GSTM1 genes could be used as genetic markers to differentiate donor cells. DISCUSSION Microchimerism could exist for a short time after microtransplantation and appears to function in hematopoietic recovery. According to published reports, cytokines secreted from microchimerisms could be detected in recipients and exhibit some function on the host. Therefore, cytokines secreted from donor cells are hypothesized to accelerate hematopoietic recovery. The evidence to prove a longer existence for microchimerism is insufficient and needs supports by additional experiments; however, we cannot deny its existence just because of the limited sensitivity of methods.