Stem cells surprise scientists

Scientists in the US and Canada have discovered a particular type of bone marrow stem cell that does not cause rejection when transplanted. The scientists have found that, unlike most stem cells transplanted from one person to another, these cells, taken from the bone marrow of adults, do not trigger an immune system response. This is because they do not carry the markers on their surface that lead to rejection.

The scientists, from Osiris Therapeutics in Baltimore, and the Dana Farber Cancer Institute in Boston, US, reported their findings in the New Scientist magazine. Meanwhile, scientists working at McGill University in Montreal, Canada, found that mesenchymal stem cells (MSCs) trigger no response from the immune system of their recipients even if transferred between species.

The researchers themselves were surprised by their findings. Annemarie Moseley, chief executive of Osiris Therapeutics, said 'it does go against our common understanding of the immune system'. So far, MSCs are known to be able to give rise to six different kinds of tissue, including bone, cartilage, tendon and muscle.