The Mismatch
Dateline: 10/29/98
Leukemia, a dread disease for its many sufferers. In many cases, a bone marrow transplant is the last hope of survival for terminally ill leukemia patients. Even then, approximately 45% of patients needing a transplant are unable to find a suitable match. In a startling development, scientists in Israel and Italy announced the development of a new technique for bone marrow transplants. The technique offers the greatly increased potential for finding a compatible donor.
One of the most difficult challenges in bone marrow transplantation is finding a donor. In many cases even close relatives are not found to be a match. There are six immunological tags or markers on chromosomes that must match in order for a donor to be compatible with the intended recipient: Three tags are inherited from one's mother; three from one's father.
In the new technique, scientists were able to reduce the number of tag matches needed to three. Three matches are always found with parents and there is a high probability that siblings and close relatives would match at least three tags.
In the procedure, the donor is given a hormone injection to induce production of stem cells. The donor's stem cells are selectively removed from the blood and "cleaned" to remove the unmatched markers. Once cleaned, the recipient's body will not reject the cells.
Of the forty-three participants in the study, 16 were free of leukemia at follow-up. The other patients had either relapsed or died. This is particularly amazing since it is likely that all 43 would have died since no six-marker donor had been found. The researchers noted that these results were comparable to results obtained with fully matched donors.
Researchers also noted that this technique overcomes both graft failure and graft-versus-host disease, two failures which account for the majority of failures in previously attempted mismatch techniques.
The researchers hope that this new technique will greatly increase the number of leukemia patients who are able to find a donor. It may one day be possible to find a donor for everyone in need of a transplant. The technique is already being tried in other countries.
What do you think? Might the number of tag matches be reduced even further? What other applications might this discovery have? Come over to the Biology Forum and share your thoughts, opinions, and feelings. 'Til next time...
