the value of minimal residual disease and diamonds

n/

ABO incompatibile graft management in pediatric transplantation

Up to 40% of donor-recipient pairs in SCT have some degree of ABO incompatibility, which may cause severe complications. The aim of this study was to describe available options and survey current practices by means of a questionnaire circulated within the EBMT Pediatric Diseases Working Party investigators. Major ABO incompatibility (donor's RBCs have antigens missing on the recipient's cell surface, towards which the recipient has circulating isohemagglutinins) requires most frequently an intervention in case of bone marrow grafts, as immediate or delayed hemolysis, delayed erythropoiesis and pure red cell aplasia may occur. RBC depletion from the graft (82%), recipient plasma-exchange (14%) were the most common practices, according to the survey. Graft manipulation is rarely needed in mobilized peripheral blood grafts. In case of minor incompatible grafts (donor has isohemagglutinins directed against recipient RBC antigens), isohemagglutinin depletion from the graft by plasma reduction/centrifugation may be considered, but acute tolerability of minor incompatible grafts is rarely an issue. According to the survey, minor ABO incompatibility was either managed by means of plasma removal from the graft, especially when isohemagglutinin titer was above a certain threshold, or led to no intervention at all (41%). Advantages and disadvantages of each method are discussed.Peer reviewe

Molecular remission induced by gemtuzumab ozogamicin associated with donor lymphocyte infusions in t(4;11) acute lymphoblastic leukemia relapsed after transplantation

n/

Platelet-Lysate-Expanded Mesenchymal Stromal Cells for the Treatment of Resistant GVHD

n/

Outcome of Children Developing Grade III-IV Acute Graft-Versus-Host Disease after Allogeneic Hematopoietic Stem Cell Transplantation

Acute graft versus host disease (aGvHD) remains one of the major causes of procedure-related morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). Information on the outcome of pediatric patients experiencing this complication is limited. We conducted a retrospective registry-based analysis on children who developed grade III-IV acute GVHD and were reported to the European Blood and Marrow Transplantation (EBMT) registry. Included in the study were children below age of 18 years who were transplanted between 2004 and 2016 (n=28109). Of these children, 1968 experienced grade III-IV acute GvHD: 1370 were had malignancies, while 598 were affected by a non-malignant disorder (NMD). Median year at HSCT was 2009 for patients with malignancies and 2010 for patients with NMD. In this latter group, as expected, the median age at HSCT was lower (5.8 years), in comparison with those affected by malignancies (9 years). The donor was an HLA-identical sibling in 576 cases and an unrelated donor in 895 cases. Umbilical cord blood (UCB) was employed in 282 cases, while a relative other than a compatible sibling in 215 cases. Overall, 1075 patients were given bone marrow (BM), while 598 received peripheral blood stem cells (PBSC). A fully myeloablative conditioning regimen has been employed in 94% of patients with malignancies in comparison with 75% of children with NMD. As a post-transplant pharmacological GvHD prophylaxis, a different strategy of immune suppressive treatment have been used: it consisted in the association of Cyclosporine-A (CSA) and Methotrexate in 40%, CSA alone in 30% and CSA plus Mycophenolate mofetil in 10% of patients. Grade III aGvHD occurred in 1383 patients (70%), while grade IV aGvHD was diagnosed in 585 (30%). Chronic GvHD occurred in 48.2% and 49.3% of patients with malignant and NMD, respectively. It was extensive in 262 (26.8%) patients with malignancies and in 111 (28%) children affected by NMD. Within patients with malignancies, the 2-year Kaplan-Meyer probability of overall survival (OS) was 65.7% (confidence interval 95, 63 - 68.4). In this group, the cumulative incidence of non-relapse mortality (NRM) was 23.1%. Notably, the occurrence of GvHD was responsible of death in 228 patients (CI 14.5%). In the NMD cohort, the 2-year Kaplan-Meyer probability of overall survival (OS) was 67.8% (confidence interval 95, 63.8 - 71.9). Sixty-one patients died to GvHD, being the 2-year cumulative incidence of GvHD-related mortality 19%. These data indicate that the occurrence of grade III-IV aGVHD is associated with a dismal outcome also in pediatric patients. The main cause of fatality is represented by NRM, while leukemia recurrence affected outcome of a lower number of children. Thus, strategies aimed at preventing this immune-mediated complication and at optimizing its treatment are desirable

Mesenchymal Stromal Cells Do Not Increase the Risk of Viral Reactivation Nor the Severity of Viral Events in Recipients of Allogeneic Stem Cell Transplantation

Mesenchymal stromal cells (MSC) are tested in clinical trials to treat graft versus host disease (GvHD) after stem cell transplantation (SCT). In vitro studies demonstrated MSC's broad immunosuppressive activity. As infections represent a major risk after SCT, it is important to understand the role of MSC in this context. We analyzed 24 patients (pts) receiving MSC for GvHD in our Unit between 2009 and 2011. We recorded viral reactivations as measured in whole blood with polymerase chain reaction for 100 days following MSC administration. In patients with a documented viral reactivation in the first 3 days following MSCs infusion the frequency of virus-specific IFNgamma-producing cells was determined through enzyme-linked immunospot assay. In our cohort of patients viral reactivation after MSC infusion occurred in 45% of the cases, which did not significantly differ from the incidence in a historical cohort of patients affected by steroid resistant GvHD and treated with conventional immunosuppression. No patient presented severe form of infection. Two cases could be checked for immunological response to viral stimulus and demonstrated virus specific T-cytotoxic lymphocyte activity. In our experience MSC infusion did not prove to trigger more frequent or severer viral reactivations in the post transplantation setting

Eligibility for allogeneic transplantation in very high risk childhood acute lymphoblastic leukemia: the impact of the waiting time.

The advantage of allogeneic transplant from compatible related donors versus chemotherapy in children with very-high-risk acute lymphoblastic leukemia in first complete remission was previously demonstrated in an international prospective trial. This study quantified the impact of time elapsed in first remission in the same cohort. Of 357 pediatric patients with very-high-risk acute lymphoblastic leukemia, 259 received chemotherapy, 55 transplantation from compatible related and 43 from unrelated donors. The 5-year disease-free survival was 44.2% overall and 42.5% for chemotherapy only patients. The chemotherapy conditional 5-year disease-free survival increased to 44.4%, 47.6%, 51.7%, and 60.4% in patients who maintained their first remission for at least 3, 6, 9, and 12 months respectively. The overall outcome was superior to that obtained with chemotherapy-only at any time-point. The relative advantage of transplant from compatible related donors in very-high-risk childhood acute lymphoblastic leukemia was consistent for any time elapsed in first remission