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• The study cohort comprised children with leukemia who underwent partially CD3+-depleted peripheral stem cell transplantation (PSCT). • Three-year overall survival was 61.8% (95% confidence interval [CI], 50.2% to 71.4%) and event-free survival was 52.0% (95% CI, 40.3% to 62.4%). • Age ≥15 years and second complete remission were associated with worse outcomes. • The incidence of severe chronic graft-versus-host disease was lower in CD3+-depleted PSCTthan in T cell-replete PSCT. Most children who may benefit from stem cell transplantation lack a matched related donor. Alternative donor transplantations with an unrelated donor (URD) or a partially matched related donor (PMRD) carry an increased risk of graft-versus-host-disease (GVHD) and mortality compared with matched related donor transplantations. We hypothesized that a strategy of partial CD3+/CD19+ depletion for URD or PMRD peripheral stem cell transplantation (PSCT) would attenuate the risks of GVHD and mortality. We enrolled 84 pediatric patients with hematologic malignancies at the Children's Hospital of Philadelphia and the Children's Hospital of Wisconsin between April 2005 and February 2015. Two patients (2.4%) experienced primary graft failure. Relapse occurred in 23 patients (27.4%; cumulative incidence 26.3%), and 17 patients (20.2%) experienced nonrelapse mortality (NRM). Grade III-IV acute GVHD was observed in 18 patients (21.4%), and chronic GVHD was observed and graded as limited in 24 patients (35.3%) and extensive in 8 (11.7%). Three-year overall survival (OS) was 61.8% (95% confidence interval [CI], 50.2% to 71.4%) and event-free survival (EFS) was 52.0% (95% CI, 40.3% to 62.4%). Age ≥15 years was associated with decreased OS (P =.05) and EFS (P =.05). Relapse was more common in children in second complete remission (P =.03). Partially CD3+-depleted alternative donor PSCT NRM, OS, and EFS compare favorably with previously published studies of T cell-replete PSCT. Historically, T cell-replete PSCT has been associated with a higher incidence of extensive chronic GVHD compared with limited chronic GVHD, which may explain the comparatively low relapse and NRM rates in our study cohort despite similar overall rates of chronic GVHD. Partial T cell depletion may expand donor options for children with malignant transplantation indications lacking a matched related donor by mitigating, but not eliminating, chronic GVHD. [ABSTRACT FROM AUTHOR]

Abstract: Impaired immunologic recovery (IR) after hematopoietic stem cell transplantation (HSCT) is associated with increased risk for infections and relapse. Stem cell source and graft manipulation influence the kinetics of IR. Partial T cell depletion of peripheral blood stem cell (PBSC) grafts is a novel alternative method of graft manipulation for children. We compared IR in children undergoing HSCT for hematologic malignancies receiving either T cell–depleted (TCD)-PBSCs (n = 55) or umbilical cord blood (UCB) (n = 21) over a 7-year period at a single institution. PBSC grafts underwent ex vivo negative selection for CD3+ cells using the CliniMACS system with partial T cell add-back. Recovery of CD4+ T cells was significantly delayed in TCD-PBSC recipients compared with UCB recipients, owing to impaired CD4+/CD45RA+ (naïve) T cell lymphopoiesis. Recovery of total CD3+ cells and CD3+/CD8+ cells was similar in the 2 groups. The TCD-PBSC recipients had a marked deficit in CD19+ and, to a lesser extent, IgA/IgM, owing to the need for B cell depletion of these grafts to attenuate the risk of lymphoproliferative disease after TCD HSCT. There were no significant between-group differences in response to mitogen stimulation, time to independence from intravenous immunoglobulin supplementation, or incidence of viral reactivation. Transplantation outcomes of relapse, transplantation-related mortality, event-free survival, and overall survival were similar in the 2 groups. Efforts to enhance IR after partial TCD-PBSC transplantation, such as selective αβ T cell depletion, hold promise for further improvement of this transplantation approach. [Copyright &y& Elsevier]

Graft versus host disease (GVHD) causes significant morbidity and mortality after allogeneic stem cell transplant (SCT). Little is known about genetic determinants of GVHD risk, including human leukocyte antigen (HLA) genotypes outside of HLA-mismatch. HLA-DQ2 and DQ8 genotypes are associated with celiac disease (CD) and are present in ≥90% of patients with CD. Both GVHD and CD are systemic inflammatory conditions that may have T cell-mediated enteropathy. We hypothesized HLA-DQ alleles associated with CD risk would confer increased risks of acute (a) and chronic (c) GVHD in pediatric SCT recipients. We performed a retrospective cohort study of children aged 0-21 years undergoing first allogeneic SCT at the Children's Hospital of Philadelphia from 10/1/12 — 7/1/16. Patients with primary graft failure or missing HLA-DQ genotypes were excluded. We grouped patients by low, moderate or high CD risk (Clin Gastroenterol Hepatol 2009, 7:966). Primary outcomes were 1) 100-day aGVHD incidence; 2) day 100 — 1-year cGVHD incidence; and 3) time to GVHD with relapse, death, secondary graft failure, second SCT, or donor lymphocyte infusion as competing risks. Logistic regressions were used to calculate odds ratios (OR) and 95% confidence intervals (CI). Sub-distribution hazard models were used to estimate crude and adjusted sub-distribution hazard ratios (sHR) in time-to-event analyses. Multivariate models were adjusted for race-ethnicity, malignant/nonmalignant SCT indication, donor/mismatch, and graft source. We identified 167 patients (mean age 9.2 ±6.2 years). Proportions by CD risk were: low-risk n=108 (64.7%), moderate n=33 (19.8%), and high n=26 (15.6%). Day 100 incidence of ≥grade 2 aGVHD was 14.4% (8.4% had ≥grade 3). cGVHD 1-year incidence was 42.7% (14% had extensive). CD risk was protective against GVHD but did not reach statistical significance (Table 1). Risk of clinically significant GVHD (≥grade 2 or any chronic) was reduced in children with CD risk in the adjusted time-to-event model (moderate: sHR 0.42, 95% CI 0.18 — 0.95, p=0.037; high: sHR 0.31, 95% CI 0.12 – 0.8, p=0.016; Figure 1A). The protective effect of high CD risk was more pronounced for severe GVHD (≥grade 3 or chronic extensive) but did not reach statistical significance (adjusted sHR 0.14, 95%CI 0.02-1.09, P = 0.061; Figure 1B). In contrast to our hypothesis, CD risk by HLA-DQ is protective against GVHD in a dose-responsive manner. Reports of HLA-DQ2 and DQ8 protecting against other non-CD autoimmune diseases (rheumatoid arthritis and inflammatory bowel disease) support our observations. These results require confirmation and evaluation in a larger patient sample to define this novel GVHD risk modifier more robustly. [ABSTRACT FROM AUTHOR]