Allogeneic hemopoietic stem cell transplantation (HSCT) is the only method currently available to cure transfusion-dependent thalassemia major that has been widely used worldwide. To verify transplantation distribution, demography, activity, policies and outcomes inside the European Group for Blood and Marrow Transplantation (EBMT), we performed a retrospective non-interventional study, extracting data from the EBMT hemoglobinopathy prospective registry database. We included 1493 consecutive patients with thalassemia major transplanted between 1 January 2000 and 31 December 2010. In total, 1359 (91%) transplants were performed on patients o18 years old, 1061 were from a human leukocyte Ag-identical sibling donor. After a median observation time of 2 years, the 2-year overall survival (OS) and event-free survival (EFS; that is, thalassemia-free survival) were 88 ± 1% and 81 ± 1%, respectively. Transplantation from a human leukocyte Ag-identical sibling offered the best results, with OS and EFS of 91 ± 1% and 83 ± 1%, respectively. No significant differences in survival were reported between countries. The threshold age for optimal transplant outcomes was around 14 years, with an OS of 90-96% and an EFS of 83-93% when transplants were performed before this age. Allogeneic HSCT for thalassemia is a curative approach that is employed internationally and produces excellent results.

Despite advances in graft-versus-host-disease (GVHD) treatment, it is estimated that overall survival (OS) at 2 years for hematopoietic cell transplantation (HCT) recipients who experience steroid-resistant GVHD is 10%. Among recent therapeutic approaches for GVHD treatment, mesenchymal stromal cells (MSCs) hold a key position. We describe a multicenter experience of 11 pediatric patients diagnosed with acute or chronic GVHD (aGVHD, cGVHD) treated for compassionate use with GMP-grade unrelated HLA-disparate donors' bone marrow-derived MSCs, expanded in platelet-lysate (PL)-containing medium. Eleven patients (aged 4-15 years) received intravenous (i.v.) MSCs for aGVHD or cGVHD, which was resistant to multiple lines of immunosuppression. The median dose was 1.2 x 10(6)/kg (range: 0.7-3.7 x 10(6)/kg). No acute side effects were observed, and no late side effects were reported at a median follow-up of 8 months (range: 4-18 months). Overall response was obtained in 71.4% of patients, with complete response in 23.8% of cases. None of our patients presented GVHD progression upon MSC administration, but 4 patients presented GVHD recurrence 2 to 5 months after infusion. Two patients developed chronic limited GVHD. This study underlines the safety of PL-expanded MSC use in children. MSC efficacy seems to be greater in aGVHD than in cGVHD, even after failure of multiple lines of immunosuppression.

The success of allogeneic hematopoietic stem cell transplantation (HSCT) from matched unrelated donors (UDs) for ␤-thalassemia may be hampered by the occurrence of graft rejection. Here, we show that the rate of this complication can be reduced by selecting 5-loci HLAmatched donors without nonpermissive mismatches at HLA-DPB1, defined according to an algorithm previously described and based on principles of central T-cell tolerance. Seventy-two consecutive patients and their UDs, prospectively selected for matching at the allelic level for HLA-A, -B, -C, -DRB, and -DQB1 loci, were enrolled in the analysis. These pairs were either DPB1 matched/permissively mismatched (n ‫؍‬ 45, control group) or had at least one nonpermissive DPB1 mismatch in the host-versus-graft (HvG; n ‫؍‬ 17) or in the graft-versus-host (GvH; n ‫؍‬ 10) direction. In multivariate analysis, the risk of rejection was significantly increased in the group with HvG disparity (RR ‫؍‬ 7.42; 95% CI ‫؍‬ 1.29-42.68; P ‫؍‬ .02) as compared to the control group. A lower, statistically significant, probability of thalassemia-free survival was found in patients belonging to the HvG group as compared to controls (RR ‫؍‬ 5.15; 95% CI ‫؍‬ 1.58-16.82; P ‫؍‬ .01). These data suggest that in patients with thalassemia, the incidence of graft failure after HSCT may be reduced by appropriate selection of UDs, with such selection taking into account the functional rules of immunogenetics.

Allogeneic hematopoietic stem cell transplantation (HSCT) in thalassemia remains a challenge. We reported a single-centre case-control study of a large cohort of 516 children and adult patients treated with HSCT or blood transfusion support and iron chelation therapy; 258 patients (median age 12, range 1-45) underwent sibling (67%) or unrelated (33%) HSCT; 97 patients were adults (age ≥ 16 years). The median follow-up after HSCT was 11 years (range 1-30). The conditioning regimen was busulfan (80.6%) or treosulfan-based (19.4%). A cohort of 258 age-sex matched conventionally treated (CT) patients was randomly selected. In transplanted patients the 30-year overall survival (OS) and thalassemia-free survival (TFS) were 82.6 ± 2.7% and 77.8 ± 2.9%, compared to the OS of 85.3 ± 2.7% in CT patients (P = NS); The incidence of grade II-IV acute and chronic graft versus host disease (GvHD) was 23.6% and 12.9% respectively. The probability of rejection was 6.9%. Transplant-related mortality (TRM) (13.8%) was similar to the probability of dying of cardiovascular events in CT patients (12.2%). High-risk Pesaro score (class 3) was associated with lower OS (OR = 1.99, 95% C.I.=1.31-3.03) and TFS (OR = 1.54, 95% C.I.=1.12-2.12). In adult patients, the 23-years OS and TFS after HSCT were 70 ± 5% and 67.3 ± 5%, compared to 71.2 ± 5% of OS in CT (P = NS). Finally, treosulfan was associated with lower risk of acute GvHD (P = .004; OR = 0.28, 95% C.I.=0.12-0.67). In conclusion, the 30-year survival rate of ex-thalassemia patients after HSCT was similar to that expected in CT thalassemia patients, with the vast majority of HSCT survivors cured from thalassemia.

Allogeneic SCT remains the only potential cure for patients with thalassemia. However, most BMT candidates lack a suitable family donor and require an unrelated donor (UD). We evaluated whether BMT using UDs in high-risk adult thalassemia patients can offer a probability of cure comparable to that reported employing an HLA-compatible sibling as donor. A total of 27 adult thalassemia patients (15 males and 12 females, median age 22 years) underwent BMT from a UD selected by high-resolution HLA molecular typing. The conditioning regimen consisted of Busulphan (BU, 14 mg/kg) plus Cyclophosphamide (CY, 120 or 160 mg/kg) in 12 cases and BU (14 mg/kg), Thiotepa (10 mg/kg) and CY (120-160 mg/kg) in the remaining 15 cases. Cyclosporine-A and short-term Methotrexate were used for graft-versus-host disease (GVHD) prophylaxis. In all, 19 patients (70%) are alive and transfusion-independent after a median follow-up of 43 months (range 16-137). A total of 10 patients (37%) developed grade II-IV acute GVHD and six (27%) chronic GVHD. Eight patients (30%) died from transplant-related causes. UD-BMT can cure more than two-thirds of adult thalassemia patients, and is a particularly attractive option for patients who are not compliant with conventional treatment.

Sinusoidal obstruction syndrome (SOS), also known as veno-occlusive disease (VOD), is a potentially life-threatening complication that may develop after hematopoietic stem cell transplantation (HSCT). The aims of this retrospective multicenter study were to evaluate the incidence of SOS/VOD in a large cohort of children transplanted in centers across Italy by applying the new European Society for Blood and Marrow Transplantation (EBMT) criteria and to analyze the risk factors underlying this complication. We retrospectively reviewed data of pediatric HSCTs performed in 13 AIEOP (Associazione Italiana di Ematologia e Oncologia Pediatrica)-affiliated centers between January 2000 and April 2016. The new pediatric EBMT criteria were retrospectively applied for diagnoses of SOS/VOD and severity grading. Among 5072 transplants considered at risk for SOS/VOD during the study period, 103 children (2%) developed SOS/VOD, and the grade was severe or very severe in all patients. The median time of SOS/VOD occurrence was 17 days after HSCT (range, 1 to 104). Sixty-nine patients (67%) were treated with defibrotide for a median time of 16 days (range, 4 to 104). In multivariable analysis age < 2 years, use of busulfan during the conditioning regimen, female gender, and hemophagocytic lymphohistiocytosis were risk factors statistically associated with the development of SOS/VOD. The overall mortality directly related to SOS/VOD was 15.5%. Overall survival at 1 year was worse in patients with SOS/VOD (P = .0033), and this difference disappeared 5 years after HSCT. Nonrelapse mortality was significantly higher 1 and 5 years after transplantation in patients who developed SOS/VOD (P < .001). Based on the application of new EBMT criteria, the overall incidence of SOS/ VOD recorded in this large Italian pediatric retrospective study was 2%. Nonrelapse mortality was significantly higher in patients who developed SOS/VOD. Identifying the risk factors associated with SOS/VOD can lead to more effective early treatment strategies of this potentially fatal HSCT complication in childhood.

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