Fooling transplant patient's immune system before operation

Main Category: Immune System / Vaccines
Also Included In: Transplants / Organ Donations
Article Date: 07 Dec 2003 - 0:00 PDT


Doctors could reduce a transplant patient's need for powerful drugs by treating him/her with cells from the donor before the operation.

This treatment redirects the immune system so that it does not attack the new organ (from the donor). Scientists in the UK have found a key gene signal that could help the new kidney.

This could lead to fewer side effects for patients (according to an article in the Journal of Clinical Investigation).

As supplies of organs diminish, the number of organs transplanted from live donors is on the increase.

Patients still have to take high doses of drugs to suppress their immune system (so as not to reject the new organ). Only in cases where the donor is a perfect match is this not necessary (an identical twin, for example).

High doses of these drugs are not good for the patient and even increases his/her chances of cancer.

The team of UK scientists are from Cambridge, Edinburgh Universities and Imperial College London. They have found a system called Notch (a key chemical signalling system) which seems to govern how the immune system functions.

When these scientists exposed a combination of these signals to some mice plus material from the future donor (two weeks before operating), the patient generated an immune response.

Amazingly, when the new organ was placed, the patient's immune system, rather than rejecting the organ, had been educated to ignore it (turn a blind eye).

The mice took four times as long to reject the new organ (untreated mice). This treatment encourages the development of T Suppressor Cells (these cells halt any immune response). In addition, they found that this treatment reduces production of T helper cells (which cause strong immune reactions).

Professor Maggie Dallman, one of the scientists from Imperial College said, 'Today, even with extensive efforts to find the best possible immunological match between donor and recipient, organ transplantation consigns the recipient to a lifetime of powerful immunosuppressive drugs that have many unwanted side-effects. Increasingly organ transplants, in the case of kidneys, liver or lung tissue occur between living relatives, so you know in advance who the donor and recipient are. Our strategy opens up the possibility of offering gentler postoperative therapy by redirecting the recipient's immune system in advance of the transplant.'

Another method under investigation is giving a 'mini bone marrow transplant' before the operation. This will probably reprogramme the immune system.

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