Project description:Although allogeneic hematopoietic cell transplantation (allo-HCT) is curative for high-risk pediatric acute myeloid leukemia (AML), disease relapse remains the primary cause of post-transplant mortality. To identify pressures imposed by allo-HCT on AML cells that escape the graft-versus-leukemia effect, we evaluated immune signatures in bone marrow samples from four pediatric patients using a multimodal single-cell approach. Downregulation of MHC class II (MHC-II) expression observed at post-transplant relapse was most profound in progenitor-like blasts and was accompanied by correlative changes in transcriptional regulation. Dysfunction of activated NK cells and CD8+ T cell subsets at the time of relapse was evidenced by the loss of IFN-γ response, TNF-a signaling via NF-kB, and IL-2/STAT5 signaling. Clonotype analysis of post-transplant relapse samples revealed expansion of dysfunctional T cells and enrichment of T regulatory and T helper cells. Using novel computational methods, our results illustrate a diverse immune-related transcriptional signature in post-transplantation relapses not previously reported in pediatric AML.
Project description:Administration of azithromycin after allogeneic hematopoietic stem cell transplantation for hematological malignancies has been associated with relapse in a randomized phase 3 controlled clinical trial. Studying 240 samples from patients randomized in this trial is a unique opportunity to better understand the mechanisms underlying relapse, the first cause of mortality after transplantation. We used multi-omics on patients' samples to decipher immune alterations associated with azithromycin intake and post-transplant relapsed malignancies. Azithromycin was associated with a network of altered energy metabolism pathways and immune subsets, including T cells biased toward immunomodulatory and exhausted profiles. In vitro, azithromycin exposure inhibited T cells cytotoxicity against tumor cells and impaired T cells metabolism through glycolysis inhibition, mitochondrial genes downregulation, and immunomodulatory genes upregulation, notably SOCS1. These results highlight that azithromycin directly affects immune cells that favor relapse, which raises caution about long-term use of azithromycin treatment in patients at high risk of malignancies.
Project description:Gene expression profile at single cell level of bone marrow (BM) T cells and hematopoietic stem and progenitor cells (HSPCs) of acute myeloid leukemia patients post allogeneic stem cell transplantation (alloSCT) of patients in complete remission (CR) and relapse (REL).
Project description:<p>Allogeneic hematopoietic cell transplantation (HCT) is the only known curative option for many hematologic disorders. After transplantation, many patients develop immune mediated disorders that may be life-threatening. Post-HCT immune mediated disorders are rare relative to other diseases but the prototype of graft versus host disease (GVHD) develops in 30-70% of patients. The morbidity and mortality associated with these HCT-associated immune mediated disorders are major barriers to successful use of transplantation to cure rare hematologic malignancies such as leukemia, lymphoma, multiple myeloma, myelodysplastic/myeloproliferative syndromes amongst other diseases.</p> <p>The purpose of this study is to characterize and more completely define the onset and course of immune mediated disorders after allogeneic HCT, focusing on participants who develop cutaneous sclerosis, bronchiolitis obliterans syndrome (BOS), late acute graft-vs.-host disease (GVHD), and chronic GVHD. <ul> <li>Of the participants undergoing allogeneic hematopoietic cell transplantation (HCT), can we, the researchers better identify who will develop immune-mediated disorders, what types of disorders participants will have, and whether these disorders will be severe or respond to currently available therapies?</li> </ul> </p> <p>This is a longitudinal study of 1118 individuals (1081 adults and 100 children). Those participating in this study will be evaluated over a 3 year period at 9 study sites. Participants will be enrolled pre-transplant, or up to day 121 post transplantation. This wide enrollment window will allow sites to use recruitment methods that are most efficient at their institutions. At least 2 years of follow-up will ensure an adequate sample size, and sufficient time for observation of the full spectrum of immune mediated disorders. The data of 1023 individuals have been submitted to dbGaP.</p>
Project description:The aim of this study is to assess the Fecal Microbiota Transplantation (FMT) efficacy in the prevention of allogeneic hematopoietic stem cell transplantation (allo-HSCT) complications and particularly Graft versus Host Disease (GvHD).
The hypothesis of this study is that allogeneic FMT may improve outcomes of these patients.
Project description:Gene products from the highly variable major histocompatibility locus, including HLA, are essential for self-recognition and immune surveillance of malignancy. Following allogeneic hematopoietic cell transplantation (alloHCT), genetic and epigenetic alterations in HLA can drive disease recurrence, making precise HLA assessment critical for determination of future therapy. However, current methods lack the sensitivity to quantify HLA transcripts at the single cell level, limiting their clinical utility. We introduce scrHLA-typing, a novel method that accurately identifies and quantifies HLA transcripts in single cells using hybridization capture and long-read sequencing. When applied to samples from patients with post-transplant relapse, scrHLA-typing successfully detected allele-specific expression of MHC gene products at clinically actionable levels. By characterizing allele expression in residual leukemia cells, our assay identified differences in expression patterns among patients. This capability highlights scrHLA-typing’s potential to improve risk stratification and guide the selection of appropriate salvage therapies, enhancing personalized treatment strategies after post-transplant relapse.
