Heterogeneity of human lympho-myeloid progenitors at the single cell level

The human hemopoietic progenitor hierarchy producing lymphoid and granulocytic-monocytic (myeloid) lineages is unclear. Multiple progenitor populations produce lymphoid and myeloid cells, but remain incompletely characterized. Here, we demonstrated cord blood lympho-myeloid containing progenitor populations - the lymphoid-primed multi-potential progenitor (LMPP), granulocyte-macrophage progenitor (GMP) and multi-lymphoid progenitor (MLP) - were functionally and transcriptionally distinct and heterogeneous at the clonal level, with progenitors of many different functional potentials present. Though most progenitors had uni-lineage myeloid or lymphoid potential, bi- and rarer multi-lineage progenitors occurred in LMPP, GMP and MLP. This, coupled with single cell expression analyses, suggested a continuum of progenitors execute lymphoid and myeloid differentiation rather than only uni-lineage progenitors being present downstream of stem cells.