A new drug taken for a few months prevented monkeys rejecting transplanted kidneys. The drug described in the June Nature Medicine also lack the side effects of immunosuppressive drugs, such as increased susceptibility to infection. Human trials are just beginning in progress, but the results of primates are "really, really incredible," said transplant immunologist Norma Kenyon of the University of Miami in Florida.
The drug is an antibody that binds to a protein called CD154, a signal that the immune system needs to launch an attack against a microbial invader or transplanted tissue. The antibody counteracts attack by binding to CD154 and preventing it from binding to its receptor.
expectationsThe strategy has far exceeded. Immunologist Allan Kirk and endocrinologist David Harlan of the Naval Medical Research Center in Bethesda, Maryland, and colleagues gave nine monkeys weekly doses of the antibody for the first month after transplant, and monthly doses for 5 months. All treatment was then arrested. More than a year later, eight of the nine are alive and well. The only death was due to complications during a routine blood test; an autopsy revealed that the monkey had normal kidney function when he died. monkeys witnesses who received conventional immunotherapy died in 9 weeks.
No one knows why the immune system in apes accept foreign tissue long after stopping the drug. Some scientists suspect that immune cells activated by the foreign organ, but lacking the CD154 signal die soon after a transplant, although it is not known why the new generation of immune cells would not recognize and attack the tissue. Others suspect that the cells "blocked" can be immune sort of protection
Scientists warn it is too early to know if the acceptance is permanent -. Activated immune cells that scientists have found in the kidneys could still lead to possible rejection. Although Christian Larsen said transplant immunologist from Emory University, "It is spectacular to have a monkey out of immunosuppression with good graft function, for more than a year."
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