Our initial experience with hematopoietic stem cell transplantation (HSCT) from a matched unrelated donor (MUD; n = 12) or a haploidentical related donor (n = 6) with T cell receptor (TCR)αβ/CD19 graft depletion in patients with Wiskott-Aldrich syndrome (WAS) (n = 18) showed a dramatic decrease in the incidence of graft-versus-host disease (GVHD) and transplantation-related mortality, with an increased overall survival (OS) of 88.9%. Unfortunately, the treatment was associated with mixed myeloid donor chimerism and secondary graft dysfunction (severe thrombocytopenia, n = 2; graft rejection, n = 5). To improve the outcome, we hypothesized that the addition of G-CSF and plerixafor to the conditioning chemotherapy would result in more complete donor stem cell engraftment. This trial was registered at www.clinicaltrials.gov (NCT03019809). A study group of patients with WAS (n = 16) underwent TCRαβ/CD19-depleted HSCT (MUD, n = 6; haploidentical, n = 10). The conditioning regimen was treosulfan-fludarabine-rabbit antithymocyte globulin-melphalan (or thiophosphamide in 1 patient) with G-CSF (10 µg/kg/day for 5 days starting on day -8) and plerixafor (240 µg/kg/day for 3 days starting on day -6). The clinical outcomes in this study were compared to those in a historical dataset (n = 18). No patients had grade III/IV acute GVHD in either the study or the historical control group. Importantly, in the patients with WAS, there was no statistical significance in OS between those who underwent HSCT from haploidentical donors and those who underwent HSCT from MUDs (93.8% versus 88.5%; P = .612). All patients in the study group had full donor chimerism in whole blood and in the CD3 compartments. The OS was 93.8%, and there were no cases of graft dysfunction. This study demonstrates the efficacy of adding G-CSF/plerixafor to the conditioning regimen before HSCT with TCRαβ/C D19 graft depletion in patients with WAS.

No abstract

PV and AL contributed equally Multiple studies from the EBMT registry and others have shown excellent survival rates after allogeneic haematopoietic stem cell transplantation (HSCT)for Wiskott-Aldrich syndrome (WAS) patients (Ozsahin et al, Blood 2008). The importance of myeloid engraftment for full disease correction has also been demonstrated (Moratto et al, Blood 2011). However, the vast majority of HSCTs in these studies were performed with (oral) busulfan/cyclophosphamide-based conditioning and in the early 2000 years or before. In 2005, the inborn errors working party (IEWP) of EBMT and ESID first recommended busulfan/fludarabine (BuFlu) or treosulfan/fludarabine (TreoFlu) based conditioning for primary immunodeficiencies such as WAS, with some centers deciding to add thiotepa (TT) to the conditioning. We performed a retrospective analysis via the EBMT and SCETIDE registries of WAS patients transplanted between 01/01/20006 and 12/31/2016 with these two regimens. The primary objective was to compare the overall (OS) and event-free survival (EFS) after HSCT with either BuFlu±TT or TreoFlu±TT conditioning. Secondary objectives included the influence of either conditioning regimen on acute and chronic GVHD, the degree of donor chimerism, incidence of secondary procedures after HSCT (2nd HSCT, stem cell boost, DLI, gene therapy or splenectomy) and rates of disease-specific complications after HSCT. At the time of this interim analysis, 174 patients were included, 92 (53%) with BuFlu±TT and 82 (47%) with TreoFlu±TT conditioning with a median age of 1.57 years (range 0.21-29.96) at HSCT and a median follow-up of 32.9 months (range 1.5-128.9). The donor was an HLA-matched sibling (MSD) in 30, a matched related donor (MRD) in 5, a matched unrelated donor (MUD, 9/10 or 10/10) in 105, a mismatched unrelated donor (MMUD, <9/10) in 9 and a mismatched family donor (MMFD) in 25 (18 with ex-vivo T-cell depletion). Stem cell source was bone marrow in 93 (53%), peripheral blood in 62 (36%) and cord blood in 18 (10%). Two year overall survival (OS) of the entire cohort was 88.6% (95% confidence interval 83.5%-93.6%). There was no significant difference in OS between patients treated with BuFlu±TT or TreoFlu±TT conditioning (2-year OS 88.1% vs. 89.5%; log-rank test p=0.7). Patients aged >5 years had a worse OS as compared to those 5 years or younger at HSCT (74.9% vs. 90.8%; log-rank test p=0.005). The type of donor had no influence on OS: 96.4% for MSD/MFD, 86.8% for MUD/MMUD and 87.7% for MMFD (log-rank test p=0.4). Whole blood chimerism was complete (>90% donor) in 60/75 evaluable patients (80%) at last follow-up or before secondary procedure (if a patient had one), 39/40 (98%) in the BuFlu±TT group and 21/35 (60%) in the TreoFlu±TT group. Twenty-six patients required a secondary procedure: stem cell boost in 4 patients, donor lymphocyte infusion in 9, 2nd HSCT in 15 and splenectomy in 1. Twenty-two of these 26 (84.6%) are alive and 14 of 16 with available chimerism data have a complete donor chimerism (>90%donor) at last follow-up. The 2-year cumulative incidence (CI) of secondary procedures was higher at 33.9% in the TreoFlu±TT versus 12.8% in the BuFlu±TT group (Gray's test p=0.017), and 2-year EFS (secondary procedure or death as event) was 61.4% in the TreoFlu±TT and 75.0% in the BuFlu±TT group (log-rank test p=0.2). Grade II-IV acute GVHD had the same incidence in both groups (100 day CI 24.4% vs. 26.3%; Gray's test p=0.849) and chronic GVHD of any grade was borderline more frequent in the TreoFlu±TT group (2 year CI 17.2% vs 6.7%; Gray's test p=0.054). The cumulative incidence of disease-specific complications occurring more than 6 months post HSCT (severe infections, bleeding, autoimmunity) was not different between the two groups (6.5% vs. 6.4%; Gray's test p=0.92). There was no malignancy reported after HSCT except for one EBV-post-transplant lymphoproliferative disorder (PTLD) 2.7 months after HSCT. In summary, HSCT with either BuFlu±TT or TreoFlu±TT conditioning reliably cures almost 90% of patients with WAS regardless of donor type. WAS-related complications are very rare events more than 6 months post HSCT. More patients required secondary procedures after treosulfan-based than busulfan-based conditioning. These data confirm the feasibility and efficacy of the regimens currently recommended by the IEWP. Disclosures Slatter: Medac: Other: Travel assistance. Chiesa:Gilead: Consultancy; Bluebird Bio: Consultancy. Kalwak:Sanofi: Other: travel grants; medac: Other: travel grants. Locatelli:Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; bluebird bio: Consultancy; Bellicum: Consultancy, Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Miltenyi: Honoraria. Sykora:Aventis-Behring: Research Funding; medac: Research Funding. Zecca:Chimerix: Honoraria. Veys:Pfizer: Honoraria; Servier: Research Funding; Novartis: Honoraria.

Digital gaming has become a regular part of life for today's pre-schoolers. Hence, there is a need to look at the integration of digital technology into the preschool education. The present study aims to examine the effect digital games have on children's behaviour and their social competence if played to reach an educational purpose (supervised play) and for fun (without educational aim). The study population consists of 54 pre-schoolers (26 girls and 28 boys), aged 4 to 6, who were recruited in Moscow, Russia. All children were divided in two groups: children playing digital games with peers (n = 28) and children playing digital games at home (n = 28). Findings revealed a higher level of social competence in the experimental group (+11.71, p 0.05) as compared to children playing without being told what they were expected to achieve. The experimental group also scored lower on Anxiety-Withdrawal (-7.94, p 0.05). A higher Anxiety-Withdrawal score normally means that a child experiences some degree of depression or anxiety, and exhibits overly dependent behaviour. The results of this study may help parents and teachers to use digital learning tools, in particular video games, effectively when working with young children.

No abstract