メディエイゴ

Four of five patients participating(1) in a trial(2) of an experimental(3) protocol(4) designed to induce(5) immune tolerance to(6) HLA-mismatched(7) kidney transplants(8) have been able to discontinue(9) immunosuppressive drugs(10). A mismatch(11) of HLA (human leukocyte antigen(12)) proteins(13) is the most difficult immunological(14) barrier(15) to transplantation(16). The report of the study conducted at Massachusetts General Hospital (MGH) appears in the January 24 New England Journal of Medicine.

"We are very encouraged by our initial success in inducing tolerance across the HLA barrier, something that has been a major goal of transplant immunology(17) for years," says David H. Sachs, MD, director of the MGH Transplantation Biology(18) Research Center, the study's senior author(19). "While we need to study this approach in a larger group of patients before it is ready for broad clinical use(20), this is the first time that tolerance to a series of mismatched(21) transplants has been intentionally(22) and successfully(23) induced."

For more than three decades(24), Sachs and his colleagues(25) have been pursuing(26) ways to induce tolerance, tricking the immune system(27) into regarding a donor(28) organ(29) as "self(30)." Over the years the team has developed an approach in which the organ recipient(31) receives bone marrow(32) from the donor along with the needed organ to produce a state called mixed chimerism(33), an immune system that blends(34) elements(35) of both the donor and recipient.

In 1998 the team first used this approach in a woman whose kidney failure(36) had been caused by the bone marrow cancer(37) multiple myeloma(38), which can be treated with marrow transplantation(39).