All blood cells develop from a single type of cell called a pluripotent cell (also known as a hematopoetic stem cell or a hemocytoblast). Pluripotent cells can give way to different lineages of cells, including lymphocytes or myelocytes. The lymphocyte lineage is composed mainly of T- and B-cells (white blood cells), while the myelocyte lineage includes a variety of immune cells, as well as red blood cells. [8:03]