Single-Unit versus Double-Unit Umbilical Cord Blood Transplantation in Children and Young Adults with Residual Leukemic Disease.

We previously reported in a French prospective randomized study that transplantation of 2 unrelated cord blood (UCB) units instead of 1 unit does not decrease the risk of transplantation failure but may enhance alloreactivity. Here we evaluated the influence of pretransplantation minimal residual disease (MRD) on leukemia relapse and survival after single- versus double-UCB transplantation (UCBT). Among 137 children and young adults who underwent UCBT in this randomized study, 115 had available data on MRD assessment done immediately before initiation of the pretransplantation conditioning regimen. MRD was considered positive at a level of ≥10-4, which was the case of 43 out of 115 patients. Overall, the mean 3-year survival probability was 69.1 ± 4.4%, and it was not significantly influenced by the MRD level: 70.7 ± 5.4% in MRD-negative (<10-4) patients (n = 72), 71.1 ± 9.4% in MRD-positive patients with 10-4 ≤ MRD <10-3 (n = 26) and 58.8 ± 11.9% in MRD-positive patients with ≥10-3 (n = 17). In the MRD-positive group, the mean risk of relapse was significantly lower in the double-UCBT arm compared with the single-UCBT arm (10.5 ± 7.2% versus 41.7 ± 10.4%; P = .025) leading to a higher mean 3-year survival rate (82.6 ± 9.3% versus 53.6 ± 10.3%; P = .031). This difference was observed only in patients who had not received antithymocyte globulin during their conditioning regimen. In the MRD-negative group, there was no differencebetween the single- and the double-UCBT arms. We conclude that even in cases of positive pretransplantation MRD, UCBT in children and young adults with acute leukemia yields a high cure rate, and that a double-unit strategy may enhance the graft-versus-leukemia effect and survival in these patients.

Single- vs double-unit cord blood transplantation for children and young adults with acute leukemia or myelodysplastic syndrome.

Transplantation of 2 unrelated cord blood (UCB) units instead of 1 has been proposed to increase the cell dose. We report a prospective randomized study, designed to compare single- vs double-UCB transplantation in children and young adults with acute leukemia in remission or myelodysplasia. Eligible patients had at least two 4-6 HLA-identical UCBs with >3 × 10(7) nucleated cells/kg for the first and >1.5 × 10(7) for the second. The primary end point was the 2-year cumulative incidence of transplantation strategy failure, a composite end point including transplant-related mortality (TRM), engraftment failure, and autologous recovery. Randomized patients who did not proceed to transplantation due to refractory disease were considered transplantation failures. A total of 151 patients were randomized and included in the intent-to-treat analysis; 137 were transplanted. Double-UCB transplantation did not decrease transplantation strategy failure (23.4% ± 4.9% vs 14.9% ± 4.2%). Two-year posttransplant survival, disease-free survival, and TRM were 68.8% ± 6.0%, 67.6% ± 6.0%, and 5.9% ± 2.9% after single-unit transplantation compared with 74.8% ± 5.5%, 68.1% ± 6.0%, and 11.6% ± 3.9% after double-unit transplantation. The final relapse risk did not significantly differ, but relapses were delayed after double-unit transplantation. Overall incidences of graft-versus-host disease (GVHD) were similar, but chronic GVHD was more frequently extensive after double-UCB transplantation (31.9% ± 5.7% vs 14.7% ± 4.3%, P = .02). In an exploratory subgroup analysis, we found a significantly lower relapse risk after double-unit transplantation in patients receiving total body irradiation without antithymocyte globulin (ATG), whereas the relapse risk was similar in the group treated with busulfan, cyclophosphamide, and ATG. Single-UCB transplantation with adequate cell dose remains the standard of care and leads to low TRM. Double-unit transplantation should be reserved for patients who lack such units. This trial was registered at www.clinicaltrials.gov as #NCT01067300.

Characterization and Genetic Analyses of New Genes Coding for NOD2 Interacting Proteins.

NOD2 contributes to the innate immune response and to the homeostasis of the intestinal mucosa. In response to its bacterial ligand, NOD2 interacts with RICK and activates the NF-κB and MAPK pathways, inducing gene transcription and synthesis of proteins required to initiate a balanced immune response. Mutations in NOD2 have been associated with an increased risk of Crohn's Disease (CD), a disabling inflammatory bowel disease (IBD). Because NOD2 signaling plays a key role in CD, it is important to further characterize the network of protein interacting with NOD2. Using yeast two hybrid (Y2H) screens, we identified new NOD2 interacting proteins (NIP). The primary interaction was confirmed by coimmunoprecipitation and/or bioluminescence resonance energy transfer (BRET) experiments for 11 of these proteins (ANKHD1, CHMP5, SDCCAG3, TRIM41, LDOC1, PPP1R12C, DOCK7, VIM, KRT15, PPP2R3B, and C10Orf67). These proteins are involved in diverse functions, including endosomal sorting complexes required for transport (ESCRT), cytoskeletal architecture and signaling regulation. Additionally, we show that the interaction of 8 NIPs is compromised with the 3 main CD associated NOD2 mutants (R702W, G908R and 1007fs). Furthermore, to determine whether these NOD2 protein partners could be encoded by IBD susceptibility genes, a transmission disequilibrium test (TDT) was performed on 101 single nucleotide polymorphisms (SNPs) and the main corresponding haplotypes in genes coding for 15 NIPs using a set of 343 IBD families with 556 patients. Overall this work did not increase the number of IBD susceptibility genes but extends the NOD2 protein interaction network and suggests that NOD2 interactome and signaling depend upon the NOD2 mutation profile in CD.

The NOD2-RICK complex signals from the plasma membrane.

NOD2 plays an important role in the innate immunity of the intestinal tract. By sensing the muramyl dipeptide (MDP), a bacterial wall component, NOD2 triggers the NF-kappaB signaling pathway and promotes the release of proinflammatory cytokines such as interleukin-8. Mutations in Nod2 (1007FS, R702W, G908R) impinge on NOD2 functions and are associated with the pathogenesis of Crohn disease, a chronic inflammatory bowel disease. Although NOD2 is usually described as a cytosolic receptor for MDP, the protein is also localized at the plasma membrane, and the 1007FS mutation delocalizes NOD2 to the cytoplasm (Barnich, N., Aguirre, J. E., Reinecker, H. C., Xavier, R., and Podolsky, D. K. (2005) J. Cell Biol. 170, 21-26; McDonald, C., Chen, F. F., Ollendorff, V., Ogura, Y., Marchetto, S., Lecine, P., Borg, J. P., and Nunez, G. (2005) J. Biol. Chem. 280, 40301-40309). In this study, we demonstrate that membrane-bound versions of NOD2 and Crohn disease-associated mutants R702W and G908R are capable of responding to MDP and activating the NF-kappaB pathway from this location. In contrast, the 1007FS mutant remains unable to respond to MDP from the plasma membrane. We also show that NOD2 promotes the membrane recruitment of RICK, a serine-threonine kinase involved in NF-kappaB activation downstream of NOD2. Furthermore, the artificial attachment of RICK at the plasma membrane provokes a constitutive and strong activation of the NF-kappaB pathway and secretion of interleukin-8 showing that optimal RICK activity depends upon its subcellular localization. Finally, we show that endogenous RICK localizes at the plasma membrane in the THP1 cell line. Thus, our data suggest that NOD2 is responsible for the membrane recruitment of RICK to induce a regulated NF-kappaB signaling and production of proinflammatory cytokines.