HLA-matched sibling transplantation with BM and CD34(+)-purified PBSCs in adult patients with high-risk severe aplastic anemia to overcome graft rejection without an increase in GVHD

Diagnosis and management of acquired aplastic anemia in childhood. Guidelines from the Marrow Failure Study Group of the Pediatric Haemato-Oncology Italian Association (AIEOP)

Acquired aplastic anemia (AA) is a rare heterogeneous disorder characterized by pancytopenia and hypoplastic bone marrow. The incidence is 2-3 per million population per year in the Western world, but 3 times higher in East Asia. Survival in severe aplastic anemia (SAA) has improved significantly due to advances in hematopoietic stem cell transplantation (HSCT), immunosuppressive therapy, biologic agents, and supportive care. In SAA, HSCT from a matched sibling donor (MSD) is the first-line treatment. If a MSD is not available, options include immunosuppressive therapy (IST), matched unrelated donor, or haploidentical HSCT. The purpose of this guideline is to provide health care professionals with clear guidance on the diagnosis and management of pediatric patients with AA. A preliminary evidence-based document prepared by a group of pediatric hematologists of the Bone Marrow Failure Study Group of the Italian Association of Pediatric Hemato-Oncology (AIEOP) was discussed, modified and approved during a series of consensus conferences that started online during COVID 19 and continued in the following years, according to procedures previously validated by the AIEOP Board of Directors.

Fludarabine/Cyclophosphamide Conditioning Regimen in Aplastic Anemia Patients Receiving Matched-Sibling Donor Transplant Is Non-inferior to ATG/Cyclophosphamide: A Single-Center Experience from Pakistan

The successful outcome of allogeneic hematopoietic stem cell transplant (HSCT) in aplastic anemia patients is driven by suitable donor selection, appropriate conditioning regimen, early intervention, and optimal supportive care after transplant. Pakistan, being a developing country, faces grave economic challenges due to meager health care budget; therefore, cost constraints remain the foremost impediment in optimizing transplant facilities for socioeconomically deprived patients. We conducted a single-center retrospective analysis of aplastic anemia patients (N = 130), who received matched sibling donor transplants from 2011 to 2019, treated with either fludarabine/cyclophosphamide (Flu/Cy) or antithymocyte globulin/cyclophosphamide (ATG/CY) conditioning regimen. Median age was 16 years (IQR, 11-20), and it ranged from 3 to 48 years. The median time from diagnosis to transplant was 3 months (IQR, 2 to 4), and it ranged from 1 to 8 months. The estimated overall survival (OS), relapse-free survival (RFS), and GvHD-free survival (GFS) were found to be 69.0%, 66.7%, and 64.3% in the ATG/Cy group while 76.1%, 72.7%, and 62.5% in the Flu/Cy group, respectively, after a median follow-up of 30 months (IQR, 8 to 55), and it ranged from 0 to 98 months for the study groups. The Flu/Cy regimen was well tolerated and was not associated with increased risk of GvHD. Hence, it may be an appropriate alternative conditioning regimen for developing countries with limited health care resources.

Effect of Stem Cell Source and Dose on Allogeneic Hematopoietic Stem Cell Transplantation in Adult Patients with Idiopathic Aplastic Anemia: Data from the Korean Aplastic Anemia Trials

OBJECTIVE

We aimed to evaluate the effect of stem cell source and dose on the survival of various donor subgroups, such as matched sibling donor (MSDs) and alternative donors (ADs), upon bone marrow (BM) or peripheral blood stem cell (PBSC) infusion in aplastic anemia (AA).

METHODS

We retrospectively investigated the effects of stem cell source and dose on allogeneic hematopoietic stem cell transplantation (alloHSCT) in AA.

RESULTS

A total of 267 patients were included in this analysis. The BM-treated group showed an association with low incidence of any-grade acute graft versus host disease (GvHD) (p < 0.001). A higher stem cell dose was related with a low incidence of extensive chronic GvHD in MSDs (p = 0.025). Multivariate analysis for overall survival (OS) revealed that only age at alloHSCT <31 years (p = 0.010) and prior platelet transfusion <86 U (p = 0.046) in MSDs and higher stem cell dose (hazard ratio = 2.596, p = 0.045) in ADs were favorable prognostic factors.

CONCLUSION

PBSCs could be preferred in AD because high stem cell dose may be easily achieved to improve the OS at the expense of acute GvHD. However, BM stem cells are preferred in MSDs.

Successful outcomes of second hematopoietic stem cell transplantation with total nodal irradiation and ATG conditioning for graft failure in adult patients with severe aplastic anemia

Data regarding the optimal approach for second allogeneic hematopoietic stem cell transplantation (HSCT) after graft failure (GF) in acquired severe aplastic anemia (SAA) are still limited and heterogeneous. We examined 24 patients who underwent second HLA-matched sibling donor (MSD) peripheral blood HSCT for GF. The reconditioning regimen (TNI-750/ATG) consisted of a single dose of total nodal irradiation (TNI, 750 cGy) and antithymocyte globulin (ATG; Thymoglobulin^®, 1.25 mg/kg/day for 3 days). All but one patient achieved successful engraftment of neutrophils (median 12 days, range 5-21) and platelets (median 15 days, range 9-316). Two patients with subsequent secondary GF achieved successful engraftment after a third HSCT from the same MSD. After a median follow-up of 57.4 months (range, 11.2-155.2), the 5-year overall survival and failure-free survival were 95.7% (95% confidence interval [CI] 87.7-100%) and 87.5% (95% CI 75.2-100%), respectively. One patient developed grade II acute graft-versus-host disease (GVHD), and the 2-year cumulative incidence of chronic GVHD was 23.5% (95% CI 8.1-43.5%). This study demonstrated successful outcomes following a second MSD HSCT in SAA after GF, and the results suggest TNI-750/ATG is a feasible reconditioning option. Future studies with larger cohorts will validate our results.

Preliminary evaluation of a highly automated instrument for the selection of CD34+ cells from mobilized peripheral blood stem cell concentrates

BACKGROUND

Cell selection is an important part of manufacturing cellular therapies. A new highly automated instrument, the CliniMACS Prodigy (Miltenyi Biotec), was evaluated for the selection of CD34+ cells from mobilized peripheral blood stem cell (PBSC) concentrates using monoclonal antibodies conjugated to paramagnetic particles.

STUDY DESIGN AND METHODS

PBSCs were collected by apheresis from 36 healthy subjects given granulocyte-colony-stimulating factor (G-CSF) or G-CSF plus plerixafor. CD34+ cells from 11 PBSC concentrates were isolated with the automated CliniMACS Prodigy and 25 with the semiautomated CliniMACS Plus Instrument.

RESULTS

The proportion of CD34+ cells in the selected products obtained with the two instruments was similar: 93.6 ± 2.6% for the automated and 95.7 ± 3.3% for the semiautomated instrument (p > 0.05). The recovery of CD34+ cells from PBSC concentrates was less for the automated than the semiautomated instrument (51.4 ± 8.2% vs. 65.1 ± 15.7%; p = 0.019). The selected products from both instruments contained few and similar quantities of platelets (PLTs) and red blood cells. The depletion of CD3+ cells was less with the automated instrument (4.34 ± 0.2 log depletion vs. 5.20 ± 0.35 log depletion; p < 1 × 10(-6) ). Removal of PLTs from PBSC concentrates by washing was associated with better CD34+ cell recovery. We explored the reasons for lower CD34+ cell recovery by the Prodigy and found that the nonselected cells for the Prodigy contained more PLTs than those for the CliniMACS Plus.

CONCLUSIONS

CD34+ cells can be effectively selected from mobilized PBSC concentrates with the CliniMAC Prodigy, but the recovery of CD34+ cells and depletion of CD3+ cells was lower than with the semiautomated CliniMACS Plus Instrument.

Second allogeneic stem cell transplant for aplastic anaemia: a retrospective study by the Severe Aplastic Anaemia Working Party of the European Society for Blood and Marrow Transplantation

We analysed the outcome of a second allogeneic haematopoietic stem cell transplant (alloHSCT) in 162 patients reported to the European Society for Blood and Marrow Transplantation between 1998 and 2009. Donor origin was a sibling in 110 and an unrelated donor in 52 transplants, respectively. The stem cell source was bone marrow in 31% and peripheral blood in 69% of transplants. The same donor as for the first alloHSCT was used in 81% of transplants whereas a change in the choice of stem cell source was reported in 56% of patients, mainly from bone marrow to peripheral blood. Neutrophil and platelet engraftment occurred in 85% and 72% of patients, after a median time of 15 and 17 days, respectively. Grade II-IV acute graft-versus-host disease (GVHD) and chronic GVHD occurred in 21% and 37% of patients, respectively. Graft failure (GF) occurred in 42 patients (26%). After a median follow-up of 3·5 years, the 5-year overall survival (OS) was 60·7%. In multivariate analysis, the only factor significantly associated with a better outcome was a Karnofsky/Lansky score ≥80 (higher OS). We conclude that a second alloHSCT is feasible rescue option for GF in SAA, with a successful outcome in 60% of cases.

Allogeneic hematopoietic cell transplantation without total body irradiation from unrelated donor in adult patients with idiopathic aplastic anemia: fludarabine versus cyclophosphamide-ATG

Total body irradiation (TBI) has traditionally been used in the conditioning regimen for allogenetic hematopoietic stem cell transplantation (alloHCT) from an unrelated donor (u-HCT). However, patients are increasingly receiving a fludarabine-based conditioning regimen without TBI, as it seemed less toxic than TBI. We need to know the clinical results of non-TBI u-HCT treatments. We retrospectively investigated the clinical outcomes of allogenetic hematopoietic cell transplantation (alloHCT) from an unrelated donor without TBI (non-TBI u-HCT) and compared the clinical outcomes of fludarabine-based (FLU group) and cyclophosphamide-ATG (Cy-ATG group) conditioning regimens. Sixty-one patients received the non-TBI conditioning regimen for u-HCT (32 in the FLU group and 29 in the Cy-ATG group). The cumulative incidence of neutrophil engraftment at 30 days, platelet>20K/μL at 30 days, acute graft-versus host disease (aGvHD) at 100 days, and chronic GvHD (cGvHD) at 2 years were 87.01%, 65.57%, 35.20%, and 26.64%, respectively. However, transplantation outcomes and overall survival rates did not differ between the FLU and Cy-ATG groups. Only infused CD34+ cells >3×10(6)kg(-1) was identified as a favorable factor for survival in the multivariate analysis. In conclusion, non-TBI u-HCT was feasible and there was no difference between the FLU and Cy-ATG groups in terms of transplantation outcomes.

Mouse Flk-1+Sca-1- mesenchymal stem cells: functional plasticity in vitro and immunoregulation in vivo

OBJECTIVES

Mesenchymal stem cells (MSCs) represent a powerful tool in regenerative medicine because of their differentiation and migration capacities. Moreover, the immunomodulatory ability of MSCs may be used to develop therapies for the treatment of autoimmune diseases.

METHODS

In this study, we isolated Flk-1Sca-1 MSCs from bone marrow (bMSCs). Next, we studied their biological characteristics and immunologic functions. We also investigated their effects on graft-versus-host disease (GVHD) associated with allogeneic bone marrow transplantation in mice.

RESULTS

Flk-1Sca-1 bMSCs were able to differentiate into fat and cartilage cells, indicating that the isolated cells had stem cell properties. They could also suppress alloantigen-induced T cell proliferation in vitro in a dose-dependent manner. Infusion of bMSCs into allogeneic bone marrow-transplanted mice alleviated the lethal GVHD that occurred in control recipient mice. There was significantly lower mortality among the recipients of the Flk-1Sca-1 bMSCs that also ameliorated the clinical symptoms and GVHD histopathology. Beneficial effects on GVHD by Flk-1Sca-1 bMSCs were also observed when MSCs were engineered to express anti-inflammatory cytokines IL-4 and IL-10 and decrease expression of proinflammatory cytokines IFN-γ, TNF-α, and IL-2.

CONCLUSION

Flk-1Sca-1 bMSCs have stem cell properties and can efficiently ameliorate the GVHD associated with allogeneic bone marrow transplantation in mice.

Rapid donor T-cell engraftment increases the risk of chronic graft-versus-host disease following salvage allogeneic peripheral blood hematopoietic cell transplantation for bone marrow failure syndromes

The risk of graft-rejection after allogeneic hematopoietic cell transplantation using conventional cyclophosphamide-based conditioning is increased in patients with bone marrow failure syndromes (BMFS) who are heavily transfused and often HLA-alloimmunized. Fifty-six patients with BMFS underwent fludarabine-based reduced-intensity conditioning and allogeneic peripheral blood progenitor cell (PBPC) transplantation at a single institution. The conditioning regimen consisted of intravenous cyclophosphamide, fludarabine, and equine antithymocyte globulin. Graft-versus-host disease (GVHD) prophylaxis included cyclosporine A alone or in combination with either mycophenolate mofetil or methotrexate. To reduce the risk of graft-rejection/failure, unmanipulated G-CSF mobilized PBPCs obtained from an HLA-identical or single HLA-antigen mismatched relative were transplanted rather than donor bone marrow. Despite a high prevalence of pretransplant HLA-alloimmunization (41%) and a heavy prior transfusion burden, graft-failure did not occur with all patients having sustained donor lympho-hematopoietic engraftment. The cumulative incidence of grade II-IV acute-GVHD and chronic-GVHD was 51.8% and 72%, respectively; with 87.1% surviving at a median follow-up of 4.5 years. A multivariate analysis showed pretransplant alloimmunization and rapid donor T-cell engraftment (≥95% donor by day 30) were both significantly (P < 0.05) associated with the development of chronic-GVHD (adjusted HR 2.13 and 2.99, respectively). These data show fludarabine-based PBPC transplantation overcomes the risk of graft-failure in patients with BMFS, although rapid donor T-cell engraftment associated with this approach appears to increase the risk of chronic-GVHD. (Clinicaltrials.gov identifier: NCT00003838).

HLA-matched sibling transplantation with G-CSF mobilized PBSCs and BM decreases GVHD in adult patients with severe aplastic anemia

BACKGROUND

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an effective treatment for severe aplastic anemia (SAA). However, graft failure and graft-versus-host disease (GVHD) are major causes of the early morbidity in Allo-HSCT.

METHODS

To reduce graft failure and GVHD, we treated fifteen patients with SAA using high- dose of HSCT with both G-CSF mobilized PB and BMSCs from HLA-identical siblings to treat patients with SAA.

RESULTS

All patients had successful bone marrow engraftment. Only one patient had late rejection. Median time to ANC greater than 0.5 × 10(9)/L and platelet counts greater than 20 × 10(9)/L was 12 and 16.5 days, respectively. No acute GVHD was observed. The incidence of chronic GVHD was 6.67%. The total three-year probability of disease-free survival was 79.8%.

CONCLUSION

HSCT with both G-CSF mobilized PB and BMSCs is a promising approach for heavily transfused and/or allo-immunized patients with SAA.