What are Monocytes? Hematopoietic stem cells (HSCs), which reside in the bone marrow give rise to blood cells in a process called hematopoiesis. HSCs differentiate into the lymphoid and myeloid lineages, which further differentiate into mature blood cell types (Figure 1). Monocytes are large agranular leukocytes of the myeloid lineage comprising between 5% – 10% […]