The paradigm of hematopoiesis. During hematopoiesis, long-term hematopoietic stem cells (LT-HSCs) differentiate into short-term hematopoietic stem cells (ST-HSCs) and subsequently into multipotent progenitors (MPPs). LT-HSCs have unlimited abilities to self-renew, while ST-HSCs have limited self-renewal capacity. MPPs differentiate into CMPs and ELPs. Erythroid and myeloid lineage cells are differentiated from CMPs, whereas cells of the lymphoid lineage are derived from ELPs. Dendritic cells are developed from recently identified CDPs. Although this model represents the most widely accepted view, alternative theories exist regarding the commitment of lineage-restricted progenitors. Abbreviations: MEP, megakaryocyte erythrocyte progenitor; GMP, granulocyte monocyte progenitor; CLP, common lymphoid progenitor; ETP, early thymic progenitor; RBC, red blood cell; Plt, platelet; Gr, granulocyte; Mac, macrophage; DC, dendritic cell; B, B cell; T, T cell; NK, natural killer cell.