Maintaining hyporesponsiveness and polarization potential of T cells after in vitro mixture of G-CSF mobilized peripheral blood grafts and G-CSF primed bone marrow grafts in different proportions

Haploidentical Hematopoietic Stem Cell Transplantation in Pediatric Transfusion-Dependent Thalassemia: A Systematic Review and Meta-Analysis

Haploidentical hematopoietic stem cell transplantation (haplo-HSCT) presents a promising therapeutic option for pediatric transfusion-dependent thalassemia, particularly in the scarcity of matched donors. Despite its potential, the comprehensive evaluation of this method through large-scale prospective studies remains lacking. This study aims to systematically summarize the efficacy and safety of haplo-HSCT in thalassemia, thereby providing further evidence-based insights for clinical practice. A comprehensive literature search was conducted across PubMed, Embase, and Web of Science databases through June 2024 to ensure a robust analysis of the available evidence. Data extraction was independently performed by 2 reviewers. The analysis utilized the inverse variance method with a 95% confidence interval (95% CI) to calculate the pooled proportion. To assess the heterogeneity among the studies, Cochran's Q test and Higgins' I-squared statistical methods were utilized. A random-effects model was employed to accommodate the variability between study results. Furthermore, subgroup analyses were explored differences in outcomes based on conditioning regimens and graft versus host disease (GVHD) prophylaxis. Conditioning regimens were categorized into reduced-intensity conditioning and myeloablative conditioning regimens. GVHD prophylaxis was classified into post-transplantation cyclophosphamide and non-post-transplantation cyclophosphamide. In this meta-analysis, we reviewed data from 10 studies encompassing 356 patients with thalassemia who underwent haplo-HSCT. Out of these, 328 patients survived until the follow-up date, resulting in a pooled overall survival rate of 92.4% (95% CI, 86.9-96.7; I² = 54.32%). The thalassemia-free survival was 84.5% (95% CI, 75.3-91.9; I² = 77.64%), and the graft failure rate was 8.1% (95% CI, 2.5-16.4; I² = 81.78%). The transplantation-related mortality stood at 7.4% (95% CI, 3.6-12.5; I² = 55.74%), with infections noted as the primary cause of death. The pooled proportion of acute graft versus host disease (aGVHD), grade 2-4 aGVHD, and grade 3-4 aGVHD were 29.6% (95% CI, 16.7-42.5, I² = 92.48%), 22.3% (95% CI, 10.1-42.1, I² = 80.06%), and 9.1% (95% CI, 2.8-17.7, I² = 67.92%), respectively. Subgroup analyses revealed no significant differences in these outcomes when comparing myeloablative conditioning to reduced-intensity conditioning, or post-transplantation cyclophosphamide to non-post-transplantation cyclophosphamide prophylaxis. However, variations in sample size, patient's age and geographic region among the studies suggest these factors as potential sources of heterogeneity. Haploidentical hematopoietic stem cell transplantation utilizes donors who are partially HLA-matched, typically family members, making it a viable option for transfusion-dependent thalassemia when fully matched donors are not available.

Old drug, new use: Recent advances for G-CSF

Granulocyte colony-stimulating factor (G-CSF), also known as colony-stimulating factor 3 (CSF3), is a proinflammatory cytokine that primarily stimulates the survival, proliferation, differentiation and function of neutrophil granulocyte progenitor cells and mature neutrophils. Over the past years, G-CSF has mainly been used to cure patients with neutropenia and as a part of chemotherapy to induct the remission for refractory/relapse leukemia. Recent studies showed that C-CSF can been used as condition regimens and as a part of preventive methods after allogeneic transplantation to improve the survival of patients and also has immunoregulation, and has promote or inhibit the proliferation of solid tumors. Therefore, in this review, we firstly describe the structure for G-CSF. Then its functions and mechanism were reviewed including the neutrophil mobilization, differentiation, migration, and inhibiting apoptosis of neutrophils, and its immunoregulation. Finally, the clinical applications were further discussed.

Modified Prophylactic Donor Lymphocyte Infusion (DLI) in an Adult T Cell Lymphoma/Leukemia (ATLL) Patient-Modality of Relapse Prevention

Adult T-cell Leukemia/Lymphoma (ATLL) is a rare but aggressive malignancy associated with the human T-cell lymphotropic virus type 1 (HTLV-1). ATLL is a challenging malignancy characterized by its aggressive nature and poor prognosis. Despite advancements in treatment, relapse rates remain high. Donor lymphocyte infusion (DLI) is a promising therapeutic option post-hematopoietic stem cell transplantation (HSCT) to prevent relapse. However, the prophylactic use of DLI in ATLL patients remains underexplored. We report the case of a 45-year-old female diagnosed with ATLL. Following induction chemotherapy and successful HSCT, a modified prophylactic DLI regimen was administered, consisting of gradually increasing doses of donor lymphocytes. The patient demonstrated a favorable response with no significant graft-versus-host disease (GVHD) and maintained remission over a 40-month follow-up period, suggesting a potential benefit of this approach. This case highlights the potential efficacy and safety of modified prophylactic DLI in ATLL patients, warranting further investigation. Our findings suggest that modified prophylactic DLI is a viable option for ATLL patients post-HSCT, offering a balance between efficacy and safety. Future research should focus on optimizing DLI protocols and exploring biomarkers for response prediction.

The graft versus leukemia effect: donor lymphocyte infusions and cellular therapy

Allogeneic hematopoietic stem cell transplantation (HSCT) is a potentially curative therapy for many hematologic malignancies as well as non-malignant conditions. Part of the curative basis underlying HSCT for hematologic malignancies relies upon induction of the graft versus leukemia (GVL) effect in which donor immune cells recognize and eliminate residual malignant cells within the recipient, thereby maintaining remission. GVL is a clinically evident phenomenon; however, specific cell types responsible for inducing this effect and molecular mechanisms involved remain largely undefined. One of the best examples of GVL is observed after donor lymphocyte infusions (DLI), an established therapy for relapsed disease or incipient/anticipated relapse. DLI involves infusion of peripheral blood lymphocytes from the original HSCT donor into the recipient. Sustained remission can be observed in 20-80% of patients treated with DLI depending upon the underlying disease and the intrinsic burden of targeted cells. In this review, we will discuss current knowledge about mechanisms of GVL after DLI, experimental strategies for augmenting GVL by manipulation of DLI (e.g. neoantigen vaccination, specific cell type selection/depletion) and research outlook for improving DLI and cellular immunotherapies for hematologic malignancies through better molecular definition of the GVL effect.

Haploidentical transplants with a G-CSF/ATG-based protocol: Experience from China

Haploidentical donor stem cell transplantation (haplo-SCT) has made great advances in recent decades. The granulocyte colony-stimulating factor (G-CSF)- and antithymocyte globulin (ATG)-based protocol, which is known as the Beijing Protocol, represents one of the current T-cell repletion strategies in haplo-SCT. The key elements of the Beijing Protocol for graft versus host disease (GvHD) prophylaxis include G-CSF inducing T-cell tolerance and altering graft cell components, as well as ATG administration exerting an immunoregulatory effect for intensive prophylaxis. This review will summarize the GvHD incidence, the underlying novel mechanism for GvHD prophylaxis, how to optimize GvHD prophylaxis, and the recent advances of the Beijing Protocol, mainly focusing on the issues of GvHD.

Pre-emptive and prophylactic donor lymphocyte infusion following allogeneic stem cell transplantation

Donor lymphocyte infusion (DLI) is an allogenic immunotherapy used after allogeneic hematopoietic stem cell transplantation. DLI takes advantage of the graft-versus-tumor effect induced by the infused CD3 + T cells, but may induce graft-versus-host disease. To date, DLI has been attempted to prevent hematological relapse after allogeneic hematopoietic stem cell transplantation in patients with mixed chimerism and molecular relapse (pre-emptive DLI), and as maintenance therapy in patients with high-risk hematological malignancies (prophylactic DLI). DLI response and efficacy depend on patient, disease, and DLI factors. This review discusses the efficacy and risks of DLI, with a focus on pre-emptive and prophylactic use.

Comparison of clinical outcomes between peripheral blood stem cells and peripheral blood stem cells plus bone marrow in myelodysplastic syndrome patients with haploidentical transplantation

The comparison of haploidentical G-CSF-mobilized peripheral blood and bone marrow transplantation (HBMT) for patients with myelodysplastic syndrome (MDS) and haploidentical G-CSF-primed peripheral blood stem cell transplantation (HPBSCT) remains unclear. We performed a retrospective analysis using a propensity score method on 140 MDS patients who received HPBSCT (n = 46) or HBMT (n = 94) with BU/CY as a conditioning regimen prior to transplantation at our center between June 2016 and June 2021. HBMT recipients were associated with a reduced incidence of grade III-IV acute GVHD (17.22% vs. 30.57%, p = 0.019) within 100 days, reduced 2-year transplant-related mortality (TRM) (14.29% vs. 28.94%, p = 0.045) and superior 2-year overall survival (OS) (81.6% vs. 66.0%, p = 0.027), progression-free survival (PFS) (80.9% vs. 61.2%, p = 0.015), and GVHD relapse-free survival (GRFS) (64.6% vs. 53.3%, p = 0.062) compared with HPBSCT, but 2-year relapse incidence (RI) (5.96% vs. 9.39%, p = 0.445) was not affected. Multivariate analysis revealed that a GPB/GBM mixture was the independent factor for a reduced incidence of grade III-IV acute GVHD (p = 0.018) and TRM (p = 0.048), improved OS (p = 0.029), PFS (p = 0.019) and GRFS (p = 0.072). Collectively, the use of a GPB/GBM mixture as stem cell grafts for haplo-HSCT in patients with MDS appears to be an optimal choice.

How to improve the outcomes of elderly acute myeloid leukemia patients through allogeneic hematopoietic stem cell transplantation

In recent years, with the gradual advancement of haploidentical transplantation technology, the availability of donors has increased significantly, along with the widespread use of reduced-intensity conditioning and the improvement of nursing techniques, giving more elderly acute myeloid leukemia (AML) patients the chance to receive allogeneic hematopoietic stem cell transplantation. We have summarized the classic and recently proposed pre-transplant assessment methods and assessed the various sources of donors, conditioning regimens, and post-transplant complication management based on the outcomes of large-scale clinical studies for elderly AML patients.

Optimized therapeutic strategy for patients with refractory or relapsed acute myeloid leukemia: long-term clinical outcomes and health-related quality of life assessment

BACKGROUND

Patients with refractory or relapsed acute myeloid leukemia (AML) have poor survival, necessitating the exploration of optimized therapeutic strategy. Here, we aimed to investigate clinical outcomes and health-related quality of life (HR-QoL) after total therapy, which included allogeneic hematopoietic stem cell transplantation (allo-HSCT), and prophylactic donor lymphocyte infusion (DLI) in the early phase after transplantation, followed by multiple measurable residual disease (MRD) and graft-versus-host disease (GvHD)-guided DLIs.

METHODS

Consecutive patients who had refractory or relapsed AML and had received non-T-cell-depleted allo-HSCT at Peking University Institute of Hematology were included in the study. If the patients achieved complete remission at 30 days after transplantation and had no evidence of relapse, severe infection, organ failure, and active GvHD at the time of planned DLI, prophylactic DLI was administered at 30 days after transplantation for human leukocyte antigen (HLA)-matched related HSCT or at 45-60 days after transplantation for haploidentical or unrelated HSCT. Subsequently, multiple DLIs were administered based on MRD results and whether they developed GvHD after transplantation.

RESULTS

A total of 105 patients were eligible. Eighty-seven patients received prophylactic DLI (group B), while 18 did not receive prophylactic DLI (group A). Among 105 patients, the cumulative incidence of grade 2-4 acute GvHD and chronic GvHD was 40.6% (95% confidence interval [CI] = 30.6%-50.6%) and 73.3% (95% CI = 67.4%-79.2%), respectively. The cumulative incidence of relapse (CIR), transplant-related mortality (TRM), and leukemia-free survival (LFS) at 5 years after transplantation were 31.5% (95% CI = 21.9%-41.1%), 22.1% (95% CI = 11.3%-32.9%), and 46.4% (95% CI = 36.8%-56.0%), respectively. In group B, the CIR, TRM, and LFS at 5 years after transplantation were 27.6% (95% CI = 17.6%-37.6%), 21.6% (95% CI = 11.2%-32.0%), and 50.8% (95% CI = 40.0%-61.6%), respectively. At the end of follow-up, 48 patients survived, and more than 90% of survivors had satisfactory recoveries of HR-QoL.

CONCLUSIONS

Our study indicated that total therapy is not only associated with decreased CIR, comparable TRM, and better long-term LFS, but also with satisfactory HR-QoL for refractory or relapsed AML, compared with those of standard of care therapy reported previously. Therefore, total therapy may be an optimized therapeutic strategy for refractory or relapsed AML.

Mining the multifunction of mucosal-associated invariant T cells in hematological malignancies and transplantation immunity: A promising hexagon soldier in immunomodulatory

Mucosal-associated invariant T (MAIT) cells are evolutionarily conserved innate-like T cells capable of recognizing bacterial and fungal ligands derived from vitamin B biosynthesis. Under different stimulation conditions, MAIT cells can display different immune effector phenotypes, exerting immune regulation and anti-/protumor responses. Based on basic biological characteristics, including the enrichment of mucosal tissue, the secretion of mucosal repair protective factors (interleukin-17, etc.), and the activation of riboflavin metabolites by intestinal flora, MAIT cells may play an important role in the immune regulation effect of mucosal lesions or inflammation. At the same time, activated MAIT cells secrete granzyme B, perforin, interferon γ, and other toxic cytokines, which can mediate anti-tumor effects. In addition, since a variety of hematological malignancies express the targets of MAIT cell-specific effector molecules, MAIT cells are also a potentially attractive target for cell therapy or immunotherapy for hematological malignancies. In this review, we will provide an overview of MAIT research related to blood system diseases and discuss the possible immunomodulatory or anti-tumor roles that unique biological characteristics or effector phenotypes may play in hematological diseases.

Comparison of Two Strategies for Prophylactic Donor Lymphocyte Infusion in Patients With Refractory/Relapsed Acute Leukemia

Prophylactic donor lymphocyte infusion (pDLI) could reduce relapse in patients with refractory/relapsed acute leukemia (RRAL) undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT), but optimal timing of pDLI remains uncertain. We compared the outcomes of two strategies for pDLI based on time from transplant and minimal residual disease (MRD) status in patients with RRAL. For patients without grade II–IV acute graft-versus-host disease (aGVHD) on day +60, pDLI was given on day +60 regardless of MRD in cohort 1, and was given on day +90 unless MRD was positive on day +60 in cohort 2. A total of 161 patients with RRAL were enrolled, including 83 in cohort 1 and 78 in cohort 2. The extensive chronic GVHD (cGVHD) incidence in cohort 2 was lower than that in cohort 1 (10.3% vs. 27.9%, P = 0.006) and GVHD-free/relapse-free survival (GRFS) in cohort 2 was superior to that in cohort 1 (55.1% vs. 41.0%, P = 0.042). The 2-year relapse rate, overall and leukemia-free survival were comparable between the two cohorts (29.0% vs. 28.2%, P = 0.986; 63.9% vs. 64.1%, P = 0.863; 57.8% vs. 61.5%, P = 0.666). Delaying pDLI to day +90 based on MRD for patients with RRAL undergoing allo-HSCT could lower extensive cGVHD incidence and improve GRFS without increasing incidence of leukemia relapse compared with pDLI on day +60.

Prediction, management, and prognosis of mixed chimerism after hematopoietic stem cell transplantation in transfusion-dependent pediatric thalassemia patients

BACKGROUND

Early-onset mixed chimerism (MC) with a high proportion of residual host cells is considered a signal of graft rejection in patients undergoing allogenic hematopoietic stem cell transplantation for transfusion-dependent thalassemia. In order to prevent graft rejection and minimize the risk of treatment-related graft-versus-host disease (GVHD), we established a hierarchical management system based on chimerism analysis.

METHOD

This retrospective study provides a comprehensive review of the characteristics, interventions, and outcomes of the 38 patients who developed MC after transplantation among the 144 pediatric thalassemia patients between July 2007 and January 2019 at our center.

RESULTS

A sibling donor, a blood type-matched donor, conditioning regimens without fludarabine, and transplants containing <10 × 10⁸ total nucleated cells/kg were identified to be associated with the development of MC. Among the 38 patients developing MC, only four patients rejected the grafts. The response rate to donor lymphocyte infusion (DLI, only for patients receiving sibling donor transplantation) and cytokine immunomodulation without DLI was 70.6% and 42.9%, respectively. Patients that developed GVHD after DLI or cytokine therapy had a more significant increase in donor cell chimerism (16%, range 0%-35%) than those without (8.5%, range -21% to 40%, P = .049). However, even when treatment-related GVHD was included, patients with MC had a lower cumulative incidence of total acute GVHD than patients with complete donor chimerism (29.2% vs 48.0%, P = .030).

CONCLUSIONS

Interventions based on chimerism analysis were effective in preventing graft rejection and did not increase treatment-related GVHD in thalassemia patients with MC.

Th2 polarization in target organs is involved in the alleviation of pathological damage mediated by transplanting granulocyte colony-stimulating factor-primed donor T cells

Acute graft-versus-host disease (aGVHD) is caused by allo-activated donor T cells infiltrating target organs. As a regulator of immune function, granulocyte colony-stimulating factor (G-CSF) has been demonstrated to relieve the aGVHD reaction. However, the role of G-CSF-primed donor T cells in specific target organs is still unknown. In this study, we employed a classical MHC-mismatched transplantation mouse model (C57BL/6 into BALB/c) and found that recipient mice transplanted with G-CSF-primed T cells exhibited prolonged survival compared with that of the PBS-treated group. This protective function against GVHD mediated by G-CSF-primed donor T cells was further confirmed by decreased clinical and pathological scores in this aGVHD mouse model, especially in the lung and gut. Moreover, we found that T cells polarized towards Th2 cells and regulatory T cells were increased in specific target organs. In addition, G-CSF treatment inhibited inducible co-stimulator (ICOS) expression and increased the expression of tolerance-related genes in recipient mice. Our study provides new insight into the immune regulatory effects of G-CSF on T cell-mediated aGVHD, especially for its precise regulation in GVHD target organs.

Evolution of the role of haploidentical stem cell transplantation: past, present, and future

INTRODUCTION

The accessibility to haplo-donors has led to an increase in the number of haplo-HSCT worldwide. A systematic search of the PubMed database between 2000 to present was performed.

AREAS COVERED

In this review, the authors discussed the most used approaches to perform haplo-HSCT and its results: T-cell depletion (TCD, including Perugia platform and its modifications) and T-cell repleted haplo (TCR, including the high-dose post-transplant cyclophosphamide strategy (Baltimore protocol) and the Beijing protocol). The improvements and modifications made to the different strategies have increased the indications of haplo-HSCT, including both malignant and nonmalignant disorders. Focusing on the Baltimore protocol, the authors review the results of the retrospective studies that have compared it to other donor transplants. The limitations of this strategy in terms of toxicity, graft complications, and GVHD are also discussed in detail. Finally, possible approaches to improve the outcomes of TCR haplo-HSCT are presented.

EXPERT OPINION

The recent advances in the field of haplo-HSCT have allowed a large number of patients with incurable diseases to benefit from this procedure despite not having a matched donor. With all available strategies, virtually no patient who needs an allogeneic transplant should be excluded by the absence of a donor.

Prophylactic donor lymphocyte infusion for relapse prevention: a meta-analysis

OBJECTIVE

Primary disease relapse (PDR) of malignant hematologic conditions after standard hematopoietic stem cell transplant (HSCT) is one of the most challenging diseases; therefore ongoing researches are aiming at relapse prevention and minimizing the transplant-related side effects. Prophylactic donor lymphocytes (pDLI) had been proposed as a valuable strategy for PDR prevention, but early studies had been discouraging due to the limited benefit and possible association with acute graft-versus-host disease (aGVHD). Therefore, we conducted a meta-analysis to evaluate the association between pDLI use, PDR, aGVHD and OS.

METHOD

We performed a comprehensive literature search in MEDLINE, Cochrane library and Embase database from inception to May 2019 for studies that evaluated the association between pDLI and PDR. We conducted a random effect meta-analysis of 9 studies involving a total of 748 participants (pDLI = 398, non-pDLI = 350) and reported the pooled odd ratio (OR) for association of pDLI use, PDR, aGVHD and OS.

RESULT

We found a significant decreased odd of PDR in the pDLI group (pooled OR = 0.42, 95% CI 0.30-0.58, I2 = 0%), but there was no significant increased odd of aGVHD (pooled OR of 0.98, 95% CI 0.56-1.72, I2 = 0.8%). We also found that there was an increased odd of overall survival (OS) (pooled OR 3.17, 95% CI 1.85-5.45, I2 = 50.2%).

CONCLUSION

There are significantly decreased odd of PDR and increased odd of OS in the pDLI group compared to the control group, but there is no statistically significant increased odd of aGVHD as suggested by previous studies. We concluded that pDLI is a potentially valuable method for post-transplant PDR prevention.

Clinical applications of donor lymphocyte infusion from an HLA-haploidentical donor: consensus recommendations from the Acute Leukemia Working Party of the EBMT

Donor lymphocyte infusion has been used in the management of relapsed hematologic malignancies after allogeneic hematopoietic cell transplantation. It can eradicate minimal residual disease or be used to rescue a hematologic relapse, being able to induce durable remissions in a subset of patients. With the increased use of haploidentical hematopoietic cell transplantation, there is renewed interest in the use of donor lymphocytes to either treat or prevent disease relapse post transplant. Published retrospective and small prospective studies have shown encouraging results with therapeutic donor lymphocyte infusion in different haploidentical transplantation platforms. In this consensus paper, finalized on behalf of the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation, we summarize the available evidence on the use of donor lymphocyte infusion from haploidentical donor, and provide recommendations on its therapeutic, pre-emptive and prophylactic use in clinical practice.

Therapeutic Outcomes of Haploidentical Allogeneic Hematopoietic Stem Cell Transplantation in Patients With Severe Aplastic Anemia: A Multicenter Study

BACKGROUND

Haploidentical donor (HID) allogeneic hematopoietic stem cell transplantation (HSCT) is an alternative curative treatment for patients with severe aplastic anemia (SAA) who do not have suitable matched related donors (MRD). The aim of this study was to compare the therapeutic outcomes of HID-HSCT with those of MRD-HSCT for SAA.

METHODS

A total of 235 SAA patients who underwent HID-HSCT (116) or MRD-HSCT (119) at 11 transplantation centers from January 2007 to January 2016 were included. Complications and survival outcomes were evaluated and compared between the 2 groups.

RESULTS

The HID group had a lower incidence of secondary graft failure but higher incidences of acute graft-versus-host disease (aGVHD) and chronic GVHD (cGVHD). However, the incidence of severe aGVHD (grades III-IV), poor graft function, and infections was comparable between groups. Patients in the HID group had a significantly lower survival and overall survival rates than those in the MRD group. The estimated 3-year survival rates for the MRD and HID groups were 82.82% and 75.00%, respectively. Ferritin levels, graft failure, poor graft function, severe aGVHD, and infections were the significant risk factors for survival.

CONCLUSIONS

The overall survival rate is acceptable for patients who underwent HID-HSCT, making it a feasible treatment choice for SAA patients.

G-CSF-induced macrophage polarization and mobilization may prevent acute graft-versus-host disease after allogeneic hematopoietic stem cell transplantation

Macrophages (MΦs) are an important immune cell population that are essential for tissue homeostasis and disease pathogenesis. MΦs are now classified as either M1, which produce pro-inflammatory cytokines, or M2, which produce antiinflammatory cytokines. The impact of granulocyte colony-stimulating factor (G-CSF) on MΦs in humans is unclear. Moreover, little is known about the association between MΦ subsets in allografts and the occurrence of acute graft-versus-host disease (aGVHD) in patients who undergo allogeneic hematopoietic stem cell transplantation (allo-HSCT). In the current study, we found that the M1/M2 ratio was markedly decreased in both G-CSF-treated bone marrow (post-BM) and G-CSF-treated peripheral blood from healthy donors. Post-BM MΦs exhibited reduced migration and increased phagocytosis. Moreover, post-BM MΦs reduced the percentage of Th1 and Tc1 lineages and increased the percentage of Th2, Tc2, and Treg lineages. Patients who received BM grafts with a higher M1/M2 ratio exhibited a higher incidence of grade 2-4 aGVHD. In summary, our data indicate that G-CSF decreases the M1/M2 ratio in BM grafts from healthy donors, which may contribute to preventing the occurrence of grade 2-4 aGVHD in patients after allo-HSCT.

Donor lymphocyte infusion for prevention of relapse after unmanipulated haploidentical PBSCT for very high-risk hematologic malignancies

Unmanipulated haploidentical peripheral blood stem cell transplantation (haplo-PBSCT) has been an established treatment to cure high-risk leukemia/lymphoma. Relapse is the main cause of treatment failure for patients with relapsed/refractory disease or with very high-risk gene mutations such as TP53, TET2, and DNMT3a. In this study, we aimed to establish the tolerance and efficacy of prophylactic donor lymphocyte infusion (DLI) with G-CSF-primed peripheral blood progenitors for prevention of relapse in these very high-risk patients after haplo-PBSCT. The prophylactic DLI was given at a median of 77 days after transplantation in 31 of 45 consecutive patients with very high-risk leukemia/lymphoma. The median dose of CD3+ cells for infusion was 1.8 × 107/kg. The 100-day incidences of acute graft-versus-host disease (GVHD) grades 2-4 and 3-4 after DLI were 55.3% and 10.2%. The 2-year incidences of chronic GVHD and severe chronic GVHD were 52.0% and 18.2%. The 2-year incidences of non-relapse mortality and relapse were 33.1% and 32.5%. The 2-year probabilities of overall survival and relapse-free survival were 40.1% and 31.9%. Poor-risk gene mutations (p = 0.029), disease in non-remission status prior to transplantation (p = 0.005), and donors older than 40 years of age (p = 0.043) were associated with relapse after DLI. In multivariate analysis, disease in non-remission status prior to transplantation was an independent risk factor of relapse (hazard ratio = 4.079; p = 0.035). These data showed the feasibility of the prophylactic DLI in the haplo-PBSCT setting and the anti-leukemic efficacy in very high-risk leukemia/lymphoma.

Unmanipulated Haploidentical Hematopoietic Stem Cell Transplantation Achieved Outcomes Comparable With Matched Unrelated Donor Transplantation in Young Acquired Severe Aplastic Anemia

Salvage haploidentical hematopoietic stem cell transplantation (haplo-HSCT) is considered in patients with severe aplastic anemia (SAA) if a matched unrelated donor (MUD) is unavailable. However, studies on haplo- and MUD transplantation in SAA are lacking. The present study retrospectively analyzed the outcomes of 89 young SAA patients who underwent unmanipulated alternative HSCT between September 2012 and September 2016 at our single center. Forty-one patients received haploidentical donors and forty-eight patients MUDs for HSCT. Most were heavily transfused and refractory to previous immunotherapy. The median durations for myeloid engraftment in the haplo- and MUD cohorts were 14 (range, 10 to 21) and 13 (range, 10 to 18) days, respectively. Compared with the MUD cohort, haplo-HSCT cohorts had an increased cumulative incidence of acute graft-versus-host disease (GVHD) grades II to IV (43.9% ± 7.8% versus 12.5% ± 4.8%, P = .001) and grades III to IV (21.1% ± 6.7% versus 6.6% ± 3.7%, P = .045) and similar limited chronic GVHD (47.7% ± 8.5% versus 38.5% ± 7.3%, P = .129) and extensive chronic GVHD (12.1% ± 6.8% versus 9.1% ± 4.3%, P = .198). The median follow-up time of the surviving patients was 26 months (range, 6 to 45). No significant differences were observed between haplo-HSCT and MUD HSCT cohorts in 3-year overall survival (80.3% ± 5.1% versus 89.6% ± 7.0%, P = .210), disease-free survival (76.4% ± 5.1% versus 89.4% ± 7.7%, P = .127), and GVHD-free failure-free survival (79.0% ± 8.6% versus 71.6% ± 9.3%, P = .976). Thus, haplo-HSCT, as salvage therapy, achieved similar outcomes as MUD HSCT in young SAA patients, thereby rendering it as an effective and safe option for SAA.

Effect of the in vivo application of granulocyte colony-stimulating factor on NK cells in bone marrow and peripheral blood

Granulocyte colony‐stimulating factor (G‐CSF) has been widely used in the field of allogeneic haematopoietic stem cell transplantation (allo‐HSCT) for priming donor stem cells from the bone marrow (BM) to peripheral blood (PB) to collect stem cells more conveniently. Donor‐derived natural killer (NK) cells have important antitumour functions and immune regulatory roles post‐allo‐HSCT. The aim of this study was to evaluate the effect of G‐CSF on donors' NK cells in BM and PB. The percentage of NK cells among nuclear cells and lymphocyte was significantly decreased and led to increased ratio of T and NK cells in BM and PB post‐G‐CSF in vivo application. Relative expansion of CD56^briNK cells led to a decreased ratio of CD56^dim and CD56^briNK subsets in BM and PB post‐G‐CSF in vivo application. The expression of CD62L, CD54, CD94, NKP30 and CXCR4 on NK cells was significantly increased in PB after G‐CSF treatment. G‐CSF treatment decreased the IFN‐γ‐secreting NK population (NK1) dramatically in BM and PB, but increased the IL‐13‐secreting NK (NK2), TGF‐β‐secreting NK (NK3) and IL‐10‐secreting NK (NKr) populations significantly in BM. Clinical data demonstrated that higher doses of NK1 infused into the allograft correlated with an increased incidence of chronic graft‐vs‐host disease post‐transplantation. Taken together, our results show that the in vivo application of G‐CSF can modulate NK subpopulations, leading to an increased ratio of T and NK cells and decreased ratio of CD56^dim and CD56^briNK cells as well as decreased NK1 populations in both PB and BM.

Update on current research into haploidentical hematopoietic stem cell transplantation

INTRODUCTION

Haploidentical stem cell transplantation (Haplo-SCT) is currently a suitable alternative worldwide for patients with hematological diseases, who lack human leukocyte antigen (HLA)-matched siblings or unrelated donors. Areas covered: This review summarizes the advancements in Haplo-SCT in recent years, primarily focusing on the global trends of haploidentical allograft, the comparison of outcomes between Haplo-SCT and other transplantation modalities, strategies for improving clinical outcomes, including donor selection, hematopoietic reconstitution promotion, and graft-versus-host disease, and relapse prevention/management, as well as the expanded indications of Haplo-SCT, such as severe aplastic anemia, myeloma and lymphoma. Expert commentary: Haploidentical allografts, including granulocyte colony-stimulating factor-based protocol and a post-transplant cyclophosphamide-based protocol, have been the mainstream strategy for Haplo-SCT. However, there are many unanswered questions in this field.

T-Cell Manipulation Strategies to Prevent Graft-Versus-Host Disease in Haploidentical Stem Cell Transplantation

Allogeneic haematopoietic stem cell transplantation (HSCT) from an human leukocyte antigen (HLA)-identical donor can be curative for eligible patients with non-malignant and malignant haematological disorders. HSCT from alternative donor sources, such as HLA-mismatched haploidentical donors, is increasingly considered as a viable therapeutic option for patients lacking HLA-matched donors. Initial attempts at haploidentical HSCT were associated with vigorous bidirectional alloreactivity, leading to unacceptably high rates of graft rejection and graft-versus-host disease (GVHD). More recently, new approaches for mitigating harmful T-cell alloreactivity that mediates GVHD, while preserving the function of tumour-reactive natural killer (NK) cells and γδ T cells, have led to markedly improved clinical outcomes, and are successfully being implemented in the clinic. This article will provide an update on in vitro strategies and in vivo approaches aimed at preventing GVHD by selectively manipulating key components of the adaptive immune response, such as T-cell receptor (TCR)-αβ T cells and CD45RA-expressing naive T cells.

Prophylactic Donor Lymphocyte Infusion (DLI) Followed by Minimal Residual Disease and Graft-versus-Host Disease-Guided Multiple DLIs Could Improve Outcomes after Allogeneic Hematopoietic Stem Cell Transplantation in Patients with Refractory/Relapsed Acute Leukemia

Patients with refractory/relapsed acute leukemia who have received allogeneic hematopoietic stem cell transplantation (allo-HSCT) are still at a high risk for relapse post-transplant. To investigate the impact of prophylactic donor lymphocyte infusion (DLI) followed by minimal residual disease (MRD) test and graft-versus-host disease (GVHD)-guided multiple DLIs to prevent relapse and improve survival in patients with refractory/relapsed acute leukemia who received allo-HSCT. A multicenter prospective study was designed. In total, 100 patients who achieved complete remission at 30 days post-transplant and had no uncontrolled infection, organ failure, or active GVHD were eligible First, prophylactic DLI was administered at 30 days after HLA-matched related HSCT or 45 to 60 days after HLA-matched unrelated HSCT or haploidentical HSCT. Subsequently, multiple DLIs were administered based on the results of MRD test and whether they developed GVHD. In addition to DLI, chemotherapy was also given to patients who had a positive MRD test. Three-year cumulative incidence of relapse, leukemia-free survival, and survival post-transplant were 32.4% (95% confidence interval, 22.4% to 42.4%), 50.3% (95% confidence interval, 40.3% to 60.3%), and 51.4% (95% confidence interval, 41.2% to 61.6%), respectively. In multivariate analysis, a positive MRD test (HR, 3.840; 95% confidence interval, 1.678 to 5.784; P= .001) and receiving 1 course of DLI (HR, 4.346; 95% confidence interval, 1.223 to 9.450, P= .023) were associated with an increased relapse risks. These data suggest that prophylactic DLI followed by MRD test and GVHD-guided multiple DLIs reduced relapse and increased survival post-transplant in patients with refractory/relapsed acute leukemia who received allo-HSCT. The study is registered at www.ClinicalTrials.gov as NCT01455272.

Prophylactic use of low-dose interleukin-2 and the clinical outcomes of hematopoietic stem cell transplantation: A randomized study

Leukemia relapse and chronic graft-versus-host disease (cGVHD) are still major obstacles of allogeneic hematopoietic stem cell transplantation (allo-HSCT). The numbers and activity of natural killer (NK) and T-regulatory cells can be increased post-transplantation by exposure to interleukin-2 (IL-2). We tested whether administering low-dose IL-2 would decrease leukemia relapse while reducing cGVHD after allotransplantation. This controlled, open-label randomized trial included 90 recipients of allotransplants. Subjects were randomized in a 1:1 ratio to either receive or not receive low-dose IL-2 during the early post-transplantation period. Patients in the IL-2 arm received a subcutaneous injection of low-dose IL-2 (1×10⁶ U/d) on day 60 after allo-HSCT. IL-2 was administered daily for 14 d followed by a 14-d hiatus. The primary endpoint was the cumulative incidence of leukemia relapse (CIR). Three-year CIRs for the IL-2 arm and control arm were 23% (range 16-30%) and 11% (range 6-15%; p = 0.20), respectively. Minimal residual disease-positive (MRD+) tests were more common in the IL-2 arm compared to the control arm (36% [range 29-44%] vs. 15% [range 10-20%], p = 0.03). The cumulative incidence of moderate-to-severe chronic GVHD (cGVHD) was lower in the IL-2 arm compared to the control arm (33% [range 26-39%] vs. 57% [range 49-64%), p = 0.02). Therefore, the 3-y GVHD-free and GVHD progression-free survival (GPFS) rates were significantly higher in the IL-2 arm compared to the control arm (47% [range 39-55%] vs. 31% [range 25-38%], p = 0.048). Blood Tregs, NK cells, and NK-cell cytotoxicity were increased in subjects in the IL-2 arm between 3 mo and 6 mo post-transplantation. Administration of low-dose IL-2 during the immediate post-transplantation period was associated with a higher GPFS but did not decrease the CIR.

Minimal residual disease- and graft-vs.-host disease-guided multiple consolidation chemotherapy and donor lymphocyte infusion prevent second acute leukemia relapse after allotransplant

BACKGROUND

Persons with acute leukemia relapsing after allotransplant and who respond to anti-leukemia interventions are at high risk of a second relapse. We studied the impact of minimal residual disease (MRD)- and graft-vs.-host disease (GvHD)-guided multiple consolidation chemotherapy and donor lymphocyte infusions (DLIs) to prevent second relapse in patients with acute leukemia relapsing post-transplant and who achieved complete remission after induction chemotherapy and DLI.

METHODS

Forty-seven subjects with acute leukemia relapsing after an allotransplant and who achieved complete remission after post-relapse induction chemotherapy and DLI were eligible. The use of consolidation chemotherapy and DLI was guided by the results of MRD testing and whether or not DLI caused acute and/or chronic GvHD. Outcomes were compared with those of 34 similar historical controls who did not receive consolidation chemotherapy and DLIs after induction chemotherapy and DLI.

RESULTS

One-year cumulative incidence of relapse (CIR; 22 % 95 % confidence interval (10, 35 %) vs. 56 % (39, 73 %); P < 0.0001), leukemia-free survival (LFS; 71 % (57, 84 %) vs. 35 % (19, 51 %); P < 0.0001), and survival (78 % (66, 90 %) vs. 44 % (27, 61 %); P < 0.0001) was significantly better in subjects than controls. In multivariate analyses, no chronic GvHD after therapy (hazard ratio (HR) = 3.56 (1.09, 11.58); P = 0.035) and a positive MRD test after therapy (HR = 21.04 (4.44, 94.87); P < 0.0001) were associated with an increased CIR.

CONCLUSION

These data suggest MRD- and GvHD-guided multiple consolidation chemotherapy and DLIs reduce CIR and increase LFS and survival compared with controls in persons relapsing after allotransplant for acute leukemia.

TRIAL REGISTRATION

ChiCTR-ONC-12002912 . Donor lymphocyte infusion for the treatment of leukemia relapse following allogeneic hematopoeitic stem cell transplant.

Haplo-identical transplantation for acquired severe aplastic anaemia in a multicentre prospective study

We conducted a prospective, multicentre study to confirm the feasibility of haplo-identical transplantation in treatment of severe aplastic anaemia (SAA) as salvage therapy, by analysing the outcomes of 101 patients who received haplo-identical transplantation between June 2012 and October 2015. All cases surviving for more than 28 d achieved donor myeloid engraftment. The median time for myeloid engraftment was 12 (range, 9-25) days and 15 (range, 7-101) days for platelets, with a cumulative platelet engraftment incidence of 94·1 ± 0·1%. With a median follow-up of 18·3 (3·0-43·6) months, recipients from haplo-identical transplantation had more cumulative incidence of grade II-IV acute graft-versus-host disease (aGVHD, 33·7% vs. 4·2%, P < 0·001), more chronic GVHD (22·4% vs. 6·6%, P = 0·014) at 1 year, but similar grade III-IV aGVHD (7·9% vs. 2·1%, P = 0·157), 3-year estimated overall survival (OS, 89·0% vs. 91·0%, P = 0·555) and failure-free survival (FFS, 86·8% vs. 80·3%, P = 0·659) when compared with 48 patients who received contemporaneous transplantation from matched related donors. Multivariate analysis showed no significant difference in engraftment and survival between the two cohorts. Both OS and FFS for the entire population correlated significantly with grades III-IV aGVHD. In conclusion, haplo-identical transplantation is a feasible choice for SAA with favourable outcomes.

Modern approaches to HLA-haploidentical blood or marrow transplantation

Allogeneic blood or bone-marrow transplantation (alloBMT) is a potentially curative treatment for a variety of haematological malignancies and nonmalignant diseases. Historically, human leukocyte antigen (HLA)-matched siblings have been the preferred source of donor cells owing to superior outcomes compared with alloBMT using other donors. Although only approximately one-third of patients have an HLA-matched sibling, nearly all patients have HLA-haploidentical related donors. Early studies using HLA-haploidentical alloBMT resulted in unacceptably high rates of graft rejection and graft-versus-host disease (GVHD), leading to high nonrelapse mortality and consequently poor survival. Several novel approaches to HLA-haploidentical alloBMT have yielded encouraging results with high rates of successful engraftment, effective GVHD control and favourable outcomes. In fact, outcomes of several retrospective comparative studies seem similar to those seen using other allograft sources, including those of HLA-matched-sibling alloBMT. In this Review, we provide an overview of the three most-developed approaches to HLA-haploidentical alloBMT: T-cell depletion with 'megadose' CD34(+) cells; granulocyte colony-stimulating factor-primed allografts combined with intensive pharmacological immunosuppression, including antithymocyte globulin; and high-dose, post-transplantation cyclophosphamide. We review the preclinical and biological data supporting each approach, results from major clinical studies, and completed or ongoing clinical studies comparing these approaches with other alloBMT platforms.

Haploidentical hematopoietic stem cell transplantation in adults with Philadelphia-negative acute lymphoblastic leukemia: no difference in the high- and low-risk groups

Allogeneic hematopoietic stem cell transplantation (HSCT) is the most effective post-consolidation therapy and curative option for adult patients with Philadelphia chromosome-negative (Ph-negative) acute lymphoblastic leukemia (ALL) in first complete remission (CR1). A human leukocyte antigen (HLA)-haploidentical related donor (haplo-RD) is one of the most important alternative sources for those without HLA-identical sibling donor (ISD). The present study aimed to evaluate the outcomes of haploidentical hematopoietic stem cell transplantation (haplo-HSCT) in adult Ph-negative ALL CR1 patients (n = 183). We produced an unmanipulated haplo-HSCT protocol including granulocyte colony stimulating factor (G-CSF) for all donors, intensive immune suppression, anti-thymocyte globulin, and combination of G-CSF-primed bone marrow harvest and G-CSF-mobilized peripheral blood stem cells harvest as the source of stem cell grafts. The median age for high-risk versus low-risk groups were 29 versus 23 years. Three-year incidences of relapse mortality and nonrelapse mortality for high-risk versus low-risk groups were 7.1% versus 11.1% (p = 0.498) and 18.0% versus 16.2% (p = 0.717), respectively. Three-year probabilities of disease-free survival and overall survival for high-risk versus low-risk groups were 67.6% versus 68.2% (p = 0.896) and 74.9% versus 72.7% (p = 0.981), respectively. Multivariate analysis showed that limited cGVHD and a lower pre-HSCT comorbidity burden were associated with better outcomes. In summary, comparable outcomes were observed among high- and low-risk Ph-negative ALL CR1 patients after haplo-HSCT. Haplo-RD could be considered for adults with Ph-negative ALL in CR1 as an important alternative source of donors in cases when no ISD is available.

Good outcome of haploidentical hematopoietic SCT as a salvage therapy in children and adolescents with acquired severe aplastic anemia

Haploidentical hematopoietic SCT (haplo-HSCT) is to be established in patients with acquired severe aplastic anemia (SAA) refractory to immunosuppressive therapy and lacking HLA-matched related or unrelated donors. Graft failure (GF) and GVHD have been major obstacles to HSCT. A total of 17 children and adolescents with SAA underwent haplo-HSCT in our center. The conditioning regimen consisted of BU, fludarabine, CY and anti-thymocyte globulin. All patients received cyclosporine, short-term MTX, mycophenolate mofetil and basiliximab for GVHD prophylaxis. Mesenchymal stem cells derived from unrelated umbilical cord were infused on day 1. Neutrophil engraftment was achieved in all 17 patients in a median time of 16 days (range 9-25 days). The median time of platelet engraftment was 22 days (range 9-95 days) in 16 patients. The cumulative incidence (CI) of II-IV acute GVHD (aGVHD) at day +100 was 30.53±11.12% and III-IV aGVHD occurred in only one patient. The CI of chronic GVHD was 21.25±13.31%. Secondary GF with autologous hematopoiesis recovery occurred in one patient. The OS was 71.60±17.00% at a median follow-up of 362 (36-1321) days. These limited promising data suggest that haplo-HSCT is feasible as a salvage therapy for children and adolescents with refractory SAA who lack matched donors.

Haploidentical hematopoietic stem cell transplantation following myeloablative conditioning regimens in hematologic diseases with G-CSF-mobilized peripheral blood stem cells grafts without T cell depletion: a single center report of 38 cases

Many Chinese patients with hematologic diseases, who need allogeneic hematopoietic stem cell transplantation (HSCT), lack a human leukocyte antigen-matched donor. To save these patients and to avoid collecting donor bone marrow graft, we adopted haploidentical peripheral blood HSCT with granulocyte colony stimulating factor (G-CSF) mobilized peripheral blood stem cells as the grafts without ex vivo T cell depletion. Thirty-eight patients were enrolled, and they received myeloablative preconditioning. Thirty-five patients attained a successful neutrophil and platelet recovery. The median time for the neutrophil recovery was 16 days (range of 10-23 days), and the median time for the platelet recovery was 19 days (range of 10-66 days). During the follow-up at a median time of 33.1 weeks (range of 1.1-412.6 weeks), eleven (28.9 %) patients developed aGVHD grade I-II and seven (18.4 %) patients developed aGVHD grade III-IV. The incidence of cGVHD was 27.6 %, and nine (23.7 %) patients died within the first 100 days after transplantation. The cumulative survival proportions at 1 and 2 years were 52.51 ± 8.57 % and 43.76 ± 9.11 %, respectively. These results suggested that the G-CSF-primed peripheral blood stem cell grafts, without in vitro T cell depletion, could be an appropriate stem cell source for Haplo-HSCT.

Improved outcomes using G-CSF-mobilized blood and bone marrow grafts as the source of stem cells compared with G-PB after HLA-identical sibling transplantation in patients with acute leukemia

This retrospective study compared the transplantation outcomes of 98 consecutive patients with acute leukemia. Allogeneic hematopoietic stem cell transplantation was performed using G-CSF-mobilized bone marrow and blood (G-BM&PB) or G-CSF-mobilized peripheral blood (G-PB) from HLA-identical sibling donors. The G-BM&PB and G-PB groups displayed significantly different neutrophil recovery rates (medians of 15 vs. 14 d, respectively; p = 0.009) but similar platelet recovery rates. The cumulative incidences of grades II-IV acute graft-versus-host disease (aGVHD) in the G-BM&PB and G-PB cohorts were similar (16.2 ± 4.7% vs. 21.8 ± 7.4%, respectively; p = 0.676), but the incidences of grades III-IV aGVHD were significantly different (5.5 ± 3.1% vs. 18.9 ± 7.1%, respectively; p = 0.042). The G-BM&PB and G-PB cohorts displayed similar cumulative incidences of chronic GVHD (cGVHD, 49.1 ± 5.7% vs. 42.7 ± 6.8%, respectively; p = 0.465), one-yr cumulative incidences of treatment-related mortality (16.5 ± 3.5% vs. 24.4 ± 4.1%, respectively; p = 0.220), and five-yr cumulative incidences of relapse (13.9 ± 4.8% vs. 26.8 ± 7.2%, respectively; p = 0.113). The five-yr probability of leukemia-free survival (LFS) was significantly higher in the G-BM&PB group than in the G-PB group (77.8 ± 5.2% vs. 57.6 ± 8.6%, respectively; p = 0.023). Multivariate analysis identified G-PB as an independent risk factor for grades III-IV aGVHD and LFS. Our results suggest that HLA-identical transplantation with G-BM&PB results in superior clinical outcomes compared with G-PB for patients with acute leukemia.

Chemotherapy followed by modified donor lymphocyte infusion as a treatment for relapsed acute leukemia after haploidentical hematopoietic stem cell transplantation without in vitro T-cell depletion: superior outcomes compared with chemotherapy alone and an analysis of prognostic factors

We retrospectively compared the antileukemic effects of chemotherapy alone and chemotherapy followed by modified donor lymphocyte infusion (DLI) in 82 patients with relapsed acute leukemia after haploidentical hematopoietic stem cell transplantation (HSCT) without in vitro T-cell depletion. We also investigated prognostic factors in patients receiving chemotherapy followed by modified DLI. Thirty-two patients received chemotherapy alone, and the remaining 50 patients received chemotherapy followed by modified DLI. In patients receiving chemotherapy followed by modified DLI, complete remission rate was significantly higher (64.0% vs. 12.5%, P = 0.000), the incidence of relapse was significantly lower (50.0% vs. 100.0%, P = 0.000), and disease-free survival was significantly improved (36.0% vs. 0.0%, P = 0.000) compared with patients receiving chemotherapy alone. Multivariate analysis demonstrated that patients with chronic graft-versus-host disease (GVHD) after intervention (P = 0.000) and patients receiving chemotherapy followed by modified DLI (P = 0.037) were associated with a lower relapse rate. Furthermore, in patients receiving chemotherapy followed by modified DLI, multivariate analysis demonstrated that chronic GVHD after modified DLI (P = 0.039) and duration of minimal residual disease (MRD) (-) ≥4 months after modified DLI (P = 0.001) were associated with a lower relapse rate. Our study is the first to suggest that chemotherapy followed by modified DLI is associated with stronger antileukemic effects and better survival in relapsed acute leukemia after haploidentical HSCT without in vitro T-cell depletion. Furthermore, our study suggests that lack of chronic GVHD and duration of MRD (-) <4 months after modified DLI are associated with higher relapse rates in patients receiving chemotherapy followed by modified DLI.

Long-term outcomes of unmanipulated haploidentical HSCT for paediatric patients with acute leukaemia

Allogeneic hematopoietic SCT is indicated for children whose disease demonstrates dismal prognosis with chemotherapy. This study aims to analyse the most recent outcomes of unmanipulated haploidentical (HID) HSCT for paediatric patients with acute leukaemia. Those from matched sibling donors (MSD) HSCT provided a parallel cohort to illustrate the benefits of HID. Conditioning regimen was modified BuCy2. Anti-thymoglobulin was used for HID. Mobilised marrow and blood stem cells were used as the grafts. All patients in HID achieved neutrophil recovery and 96.7% platelet recovery. In HID, the incidences of acute GVHD 3-4 and extensive chronic GVHD were 14.3 and 26.6%. Play-performance score 90-100% was recorded in 79.7% of all survivors. The 5-year leukaemia-free survival (LFS) in CR1, CR2, beyond CR2 or non-remission were 68.9%, 56.6%, 22.2% and 82.5%, 59.4%, 42.9% for ALL and AML, respectively. In MSD group, LFS for ALL and AML in CR1 were 62.5 and 71.7%. Outcomes of the HID HSCT for paediatric patients with acute leukaemia showed benefits that were similar to those of the parallel cohort of MSD HSCT.

Advancement of human leukocyte antigen-partially matched related hematopoietic stem cell transplantation

Allogeneic hematopoietic stem cell transplantation (HSCT) is one of the most effective options for hematological malignancies, and human leukocyte antigen-partially matched related donors (PMRDs) are a valuable option for HSCT. Several protocols (with or without ex vivo T-cell depletion (TCD)) have been established worldwide. TCD including CD34(+) positive selection and CD3/CD19 depletion has successfully overcome the human leukocyte antigen disparity. However, TCD is associated with prolonged immune deficiencies, increased risks of infectious complications, and high transplantation-related mortality. PMRD HSCTwithout ex vivo TCD is well developed, and numerous patients have benefitted from it. Here, we review the literature on PMRD HSCT.

Cellular mechanism for granulocyte-colony stimulating factor in the prevention of graft-versus-host disease in combined bone marrow and peripheral blood transplantation for hematological malignancies: the composition in collection

Despite improvements in transplant immunology and clinical and supportive care, acute graft-versus-host disease (aGVHD) remains a clinical challenge and a major cause of morbidity and mortality for patients after allogeneic hematopoietic stem cell transplantation (HSCT). Many ways have been used to prevent and treat aGVHD, however, long-term survival remains poor. The key to improve aGVHD outcomes may, in fact, rest upon successful initial therapy. The HLA-matched HSCT was limited by the shortage of suitable donors. Unmanipulated haploidentical/mismatched related transplantation with combined granulocyte-colony stimulating factor (G-CSF)-mobilized peripheral blood stem cells and G-CSF-mobilized bone marrow as a stronger aGVHD inhibition and graft-versus-leukemia effect, has been developed as an alternative transplantation strategy for patients with hematologic malignancies for the advantage of immediate donor availability, ability to select the best of many relatives, controlled graft composition and immediate access to donor-derived cellular therapies if required after transplantation. G-CSF is a potent hematopoietic cytokine, which is produced by fibroblasts, monocytes, and endothelial cells. G-CSF regulates production of neutrophils within the bone marrow and affects neutrophil progenitor proliferation, maturation and is also involved in mobilization of granulocytes, stem and progenitor cells, which has an important role in this transplantation. In this article, we review the possible mechanism for this combined G-CSF-mobilized HSCT in the prevention of aGVHD. Monocytes, T cells, Tregs cells, DC, adhesive molecule, NK cell/KIR ligand mismatching and mesenchymal stem cells may be involved in this transplantation.

Risk stratification–directed donor lymphocyte infusion could reduce relapse of standard-risk acute leukemia patients after allogeneic hematopoietic stem cell transplantation

We studied the impact of risk stratification–directed interventions for minimal residual disease (MRD) on relapse and disease-free survival (DFS) prospectively in 814 subjects with standard-risk acute leukemia receiving allotransplantation in first or second complete remission. A total of 709 subjects were MRD− after transplantation (Group A); 105 subjects were MRD+, 49 received low-dose IL-2 (Group B), and 56 received modified donor lymphocyte infusion (DLI) with or without low-dose IL-2 (Group C). Posttransplantation immune suppression for GVHD was also modified based on MRD state. The cumulative risk of relapse was significantly less and DFS was significantly better in subjects in Group C than in subjects in Group B (P = .001 and P = .002, respectively), but was not different from subjects in Group A (P = .269 and P = .688, respectively). Multivariate analyses confirmed that MRD state and modified DLI were significantly correlated with relapse (P = .000, odds ratio [OR] = 0.255 and P = .000, OR = 0.269) and DFS (P = .001, OR = 0.511 and P = .006, OR = 0.436, respectively). These data suggest that risk stratification–directed interventions with modified DLI in patients with standard-risk acute leukemia who are MRD+ after transplantation may improve transplantation outcomes.

Allogeneic hematopoietic stem cell transplantation in China: where we are and where to go

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an effective and sometimes the only curative therapy for patients with certain hematological diseases. Allo-HSCT has been practiced in China for approximately 30 years, and great improvements have been made within the past decade, particularly in fields such as the haploidentical HSCT system, strategies to overcome relapse and GVHD, and modified HSCT for elderly patients. This review will describe the current situation and provide a prospective of these unique aspects of Allo-HSCT in China.

The chemokine system in allogeneic stem-cell transplantation: a possible therapeutic target?

Further improvements in allogeneic stem-cell transplantation will probably depend on a better balance between immunosuppression to control graft-versus-host disease and immunological reconstitution sufficient to ensure engraftment, reduction of infection-related mortality and maintenance of post-transplant antileukemic immune reactivity. The chemokine network is an important part of the immune system, and, in addition, CXCL12/CXCR4 seem to be essential for granulocyte colony-stimulating factor-induced stem-cell mobilization. Partial ex vivo graft T-cell depletion based on the expression of specific chemokine receptors involved in T-cell recruitment to graft-versus-host disease target organs may also become a future therapeutic strategy; an alternative approach could be pharmacological inhibition (single-receptor inhibitors or dual-receptor inhibitors) in vivo of specific chemokine receptors involved in this T-cell recruitment. Future clinical studies should therefore be based on a better characterization of various immunocompetent cells, including their chemokine receptor profile, both in the allografts and during post-transplant reconstitution.

Haploidentical hematopoietic stem cell transplantation in hematologic malignancies with G-CSF mobilized bone marrow plus peripheral blood stem cells grafts without T cell depletion: a single center report of 29 cases

Haploidentical Hematopoietic stem cell transplantation (Haplo-HSCT) has provided an alternative option since virtually all patients have an immediately available donor. Here, we report the results of Haplo-HSCT with granulocyte-colony-stimulating factor (G-CSF) mobilized bone marrow grafts plus peripheral blood stem cells as the grafts without T-cell depletion. Twenty-nine patients with the mean age of 27.27 years (ranging from 15 to 51 years) were enrolled in this study, and 10 cases were in high risk status. The patients received myeloablative preconditioning with or without total body irradiation and acute graft-versus-host disease (GVHD) prophylaxis consisting of basiliximab, cyclosporine A, methotrexate, mycophenolate mofetil and a rabbit anti-thymocyte globulin. All the patients attained successful neutrophil and platelet recovery. The mean times for neutrophil and platelet recovery were 17.1 and 20.9 days, respectively. During the follow-up at a median time of 30.69 months (ranging from 3 to 76 months), nine patients developed aGVHD grade II-IV, including two developed grade III-IV GVHD after donor lymphocyte infusion. The incidence of cGVHD was 48.3%. 13 patients died within the first two years after transplantation, and the total disease-free survival rate longer than 2 years was 55.2%. These results suggest that G-CSF-primed bone marrow plus peripheral blood stem cell grafts are an appropriate stem cell source for Haplo-HSCT and large scale investigations are needed to confirm this protocol.

Prevention of relapse using granulocyte CSF-primed PBPCs following HLA-mismatched/haploidentical, T-cell-replete hematopoietic SCT in patients with advanced-stage acute leukemia: a retrospective risk-factor analysis

The role of donor lymphocyte infusion (DLI) in the prophylaxis of relapse has not been defined. We retrospectively analyzed the data from 88 patients with advanced-stage acute leukemia after HLA-mismatched/haploidentical hematopoietic SCT (HSCT) whose treatment did (n=61) or did not (n=27) include granulocyte CSF (GCSF)-primed PBPCs infusion (GPBPCI). The two groups were compared with respect to relapse and OS. Further, a detailed analysis of risk factors was performed. The 2-year cumulative incidence of relapse in patients receiving prophylactic GPBPCI and not receiving prophylactic GPBPCI were 36% and 55% (P=0.017), respectively. Estimated survival at 3 years was 31% for patients receiving prophylactic GPBPCI and 11% for patients not receiving prophylactic GPBPCI (P=0.001). The three-year probability of leukemia-free survival was also higher in patients who received prophylactic GPBPCI (22%) compared with patients who did not (11%) (P=0.003). Multivariate analysis for relapse showed that use of prophylactic GPBPCI after transplantation was an independent prognostic factor (P=0.025). Higher OS was associated with use of prophylactic GPBPCI (P=0.002), AML (P=0.027) and female sex (P=0.023). Our results suggest that use of prophylactic GPBPCI may increase survival of patients with advanced-stage acute leukemia who receive HLA-mismatched/haploidentical HSCT.

The effect of HLA disparity on clinical outcome after HLA-haploidentical blood and marrow transplantation

The relative importance of various human leukocyte antigen (HLA) loci has not been established for unmanipulated HLA-mismatched/haploidentical transplantation. To address this question, we analyzed the impact of HLA-A, HLA-B, HLA-DRB1, HLA-DRB3, HLA-DRB4, and HLA-DRB5 on the outcome of HLA-haploidentical transplantation. Four hundred and eighty-one donor-recipient pairs were fully typed before transplantation. In univariate analysis, HLA-B mismatch not only demonstrated significant adverse effects on acute graft-versus-host disease (GVHD) and transplant-related mortality but also was associated with reduced overall survival and leukemia-free survival (LFS). In multivariate analysis, HLA-B mismatch remained the independent risk factor for acute GVHD and transplant-related mortality. The high risk of disease and the female donor were found to be significant factors for reduced overall survival and LFS. Furthermore, multiple mismatch of the HLA locus was found to have no synergistic adverse effect on outcomes. Our results suggest that prospective matching of patients and donors for HLA-B antigen in the unshared HLA haplotype is warranted for HLA-mismatched/haploidentical transplantation.

The impact of graft composition on clinical outcomes in pediatric patients undergoing unmanipulated HLA-mismatched/haploidentical hematopoietic stem cell transplantation

OBJECTIVE

In pediatric patients, the association of graft composition with clinical outcomes after unmanipulated haploidentical hematopoietic stem cell transplantation has not been well defined. Therefore, the impact of graft composition on transplant outcomes was evaluated.

METHODS

We examined the absolute numbers and relative proportions of CD3+, CD4+, CD8+, CD14+, and CD34+ cells contained in allografts of 103 children who underwent unmanipulated HLA-mismatched/haploidentical hematopoietic stem cell transplantation (HSCT) without in vitro T cell depletion.

RESULTS

Multivariate analysis showed that a high CD34+ cell dose in G-CSF-primed bone marrow and peripheral blood grafts (G-PB) was related to accelerated platelet engraftment (P = 0.004). A higher CD3/CD14 ratio in G-PB (≥ 1.30) was associated with grade II-IV acute graft-versus-host disease (GVHD) (HR = 3.552; 95%CI 1.015-12.428, P = 0.047). In addition, only a heavier donor weight (HR = 5.837; 95%CI 1.841-18.513, P = 0.003) and a higher ratio of CD3/CD14 in the total graft (HR = 9.752; 95%CI 1.834-51.865, P = 0.008) were associated with worse overall survival. No aspect of graft composition affected neutrophil engraftment or disease relapse, though occurrence of chronic GVHD and a higher CD3/CD14 ratio in G-PB and total graft may reflect a lower incidence of relapse without statistical significance.

CONCLUSIONS

The dose of CD34+ cells and the CD3/CD14 ratio in allografts seem to have prognostic value for engraftment and clinical outcomes in pediatric patients undergoing unmanipulated haploidentical hematopoietic stem cell transplantation. A lower CD3/CD14 ratio in allografts demonstrated a survival benefit.

Coinfusion of mesenchymal stromal cells facilitates platelet recovery without increasing leukemia recurrence in haploidentical hematopoietic stem cell transplantation: a randomized, controlled clinical study

Previous studies have suggested that mesenchymal stromal cells (MSCs) enhance the engraftment of hematopoietic stem cells and modulate the host's immune response. However, there are no randomized studies to confirm these results. Moreover, there are some concerns about the risk of tumor recurrence because of the immunosuppressive property of MSCs. We conducted an open-label, randomized phase II clinical study to assess the outcome of MSC coinfusion (3-5 × 10(5) cells/kg) during haploidentical hematopoietic stem cell transplantation. From June 2007 to June 2008, a total of 55 patients who were diagnosed with leukemia in complete remission entered the study (27 in the treatment group and 28 in the control group). No immediate or long-term toxic side effects related to MSC infusion were noted, and the median times of white blood cell and platelet engraftment were comparable between the 2 groups. However, within 100 days, the time to a platelet concentration of >50 × 10(9) cells/L was markedly faster in the treatment group compared with the control group (22 days vs. 28 days; P = 0.036). Stromal-derived factor-1α (SDF-1α) reached a peak concentration more rapidly in the treatment group compared with the control group (8th vs. 16th day). The concentrations of SDF-1α, thrombopoietin (TPO), and interleukin-11 were also elevated in the MSC-treated group compared with the control group. The accumulative occurrence rate of acute graft-versus-host disease greater than grade 2 was 51.8% and 38.9% in the treatment and control groups (P = 0.422), respectively, whereas the occurrence rate of chronic graft-versus-host disease was 51.4% and 74.1% (P = 0.261), respectively. Through March 2010, which marked 2 years, the overall survival rate was 69.7% for the MSC-treated group and 64.3% for the control group (P = 0.737). Three patients in the treatment group and 2 patients in the control group experienced a hematological relapse and died of leukemia.

IL-17-producing T cells contribute to acute graft-versus-host disease in patients undergoing unmanipulated blood and marrow transplantation

The aim of this study was to investigate the effects of IL-17-producing T cells, including Th17 and Tc17 cells, on acute graft-versus-host disease (aGVHD) in patients who had undergone granulocyte colony-stimulating factor (G-CSF)-mobilised peripheral blood progenitor cell (PBPC) and G-CSF-primed bone marrow (G-BM) transplantation. Allografts from forty-one patients were analysed for IL-17-producing T cells with respect to aGVHD. Furthermore, ten patients with aGVHD onset were monitored for the presence of Th17 cells in the peripheral blood by flow cytometry. Patients who received a higher dose of Th17 cells in the G-BM (>8.5 × 10(4) /kg, p=0.005) or a higher dose of Tc17 cells in PBPC (>16.8 × 10(4) /kg, p=0.001) exhibited a higher incidence of aGVHD. An increased Th17 population (up to 4.99% CD4(+) T lymphocytes) was observed in patients with aGVHD onset. In contrast, the percentage of Th17 population decreased drastically in aGVHD patients following treatment to achieve partial and complete remission (p=0.013 and p=0.008, respectively). All percentages of Th17 and Tc17 cells were significantly reduced after in vivo G-CSF application. Our results suggested that IL-17-producing T cells contributed to aGVHD. The application of G-CSF in vivo aided in reducing the occurrence of aGVHD through a decrease in IL-17 secretion by T cells.