Single_cell_HSC_colony_WGS_many_years_post_allogeneic_bone_marrow_transplant

This study looks at human donors and recipients of allogeneic blood & marrow marrow transplantation. Each transplant "pair" (donor & recipient) underwent the transplant procedure 10 -30 years prior to sampling - the majority for an underlying diagnosis of leukemia. We will perform whole-genome sequencing on tens to hundreds of single HSPC (haematopoietic stem and progenitor cell)-derived colonies per individual. We will infer the phylogeny of these cells (those from both donor & recipient within a pair) by analysing the somatically acquired mutations within each cell. The structure of the phylogeny will allow estimates of hitherto unknown parameters such as the number of HSCs that engraft long-term, the dynamics of the engraftment process on the HSC level, and the additional mutation burden acquired through the arduous transplant procedure.

Type: Whole Genome Sequencing
Archiver: European Genome-Phenome Archive (EGA)

1 Dataset

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Dataset ID	Description	Technology	Samples
EGAD00001010872	Allogeneic haematopoietic cell transplantation (HCT) replaces the stem cells responsible for blood production with those harvested from a donor, and is received by 40,000 patients worldwide each year. To quantify dynamics of long-term stem cell engraftment, we sequenced whole genomes of 2,824 single-cell-derived haematopoietic colonies from blood samples of 10 donor-recipient pairs taken 9-31 years after HLA-matched sibling HCT. With younger donors, 10,000-50,000 stem cells had engrafted and were still contributing to haematopoiesis at time of sampling, but estimates were 10-fold lower with older donors. Engrafted stem cells made multilineage contributions to myeloid, B-lymphoid and T-lymphoid populations, although individual clones often showed biases towards one or other mature cell type. Recipients had lower clonal diversity than matched donors, equivalent to ~10-15 years of additional ageing, arising from up to 25-fold greater expansion of stem cell clones. An HCT-related population bottleneck alone could not explain these differences: instead, phylogenetic trees evinced two distinct modes of HCT-specific selection. In 'pruning selection', cell divisions underpinning recipient-enriched clonal expansions had occurred in the donor, preceding transplant - their selective advantage derived from preferential mobilisation, harvest, survival ex vivo or initial homing. In 'growth selection', cell divisions underpinning clonal expansion occurred through proliferative advantage in the recipient's marrow after homing - clones with multiple driver mutations especially demonstrated this pattern. Uprooting stem cells from their native environment and transplanting them to foreign soil exaggerates selective pressures, distorting and accelerating the loss of clonal diversity compared to the unperturbed haematopoiesis of donors.	Illumina HiSeq 2500 Illumina NovaSeq 6000	1