Maisonneuve-Rosemont Hospital Université de Montréal

Hematopoietic stem cells (HSCs)

HSCs: Versatile multipotent stem cells

Stem cells are classified into four different types, depending on their capacity to differentiate.

The first type, embryonic stem cells, is what begins to form a human being during the first four days following conception.

Following that, 2 to 8 embryonic stem cells divide into about 40 of what are known as pluripotent stem cells, which will produce the 220 different kinds of cells—heart, lung, nerve, blood, and others— found in the human body.

Another type, known as multipotent or somatic stem cells, is found in adults. This kind of stem cell can differentiate into a limited number of different cells. For example, the hematopoietic stem cells found in bone marrow can differentiate into immune and white, red and platelet blood cells.

Finally, the human body also contains unipotent stem cells, which can only differentiate into a single type of cell, such as those found in the skin and in the micro-organisms of the intestinal flora.

In the case of patients with cancer or certain blood disorders, therefore, it is hematopoietic stem cells that are used in transplants.