There are four blood groups -- A, B, AB and O -- and two rhesus types, positive and negative
© AFP Mychele Daniau

WASHINGTON (AFP) - "Limitations in the supply of blood can have potentially life-threatening consequences for patients with massive blood loss," said Robert Lanza, chief scientific officer at Advanced Cell Technology (ACT), a Worcester-based company.

"Embryonic stem cells represent a new source of cells that can be propagated and expanded indefinitely, providing a potentially inexhaustible source of red blood cells for human therapy.

"We can currently generate 10 to 100 billion red blood cells from a single six-well plate of stem cells," he said in a paper published online in the Blood journal.

Microscopic view of embryonic stem cells
© AFP/File Mauricio Lima

"The identification of a stem cell line with "O -" blood-type would permit the production of compatible "universal donor" blood," Lanza added.

The "O" blood type is a universal blood type and the only one that can be transfused to people with other blood types.

A blood type, or a blood group, is a classification of blood based on the presence or absence of inherited antigenic substances on the surface of red blood cells.

©AFP