Cord Blood Transplants Without Immune Suppression

Tempe, Arizona -

The current use of cord blood as a substitute for bone marrow in individuals lacking an appropriate donor has made a tremendous impact on treatment of various hematological malignancies. Cord blood has several advantages to bone marrow, including reduced HLA matching requirements (4/6 is acceptable, wherease bone marrow has to be 6/6), widespread availability, and reduced risk of transmitting infections.

Although numerous scientists have written that cord blood may be able to differentiate into a wide variety of tissues, the use of cord blood outside hematological reconstitution has been limited. This is because the current dogma is that in order for cord blood transplants to work, and inhibition of the recipient immune system must occur to, on the one hand make "room" for the new cells, and on the other hand so that the new cells do not cause graft versus host.

In a recent paper (Riordan et al. Cord blood in regenerative medicine: do we need immune suppression? J Transl Med. 2007 30;5:8) a compelling case is made that there is no need to suppress the immune system of the recipient when cord blood is used for specific uses.

Essentially, the authors describe the fact that specific types of stem cells can live in a fully allogeneic environment without need for immune suppression, and also that the risk of GVHD with cord blood appears to be very small.

The authors belong to a company called Medistem which appears to be developing products using cord blood stem cells.