8/31/06

bone marrow transplant as cure for aids?

i swear i thought of this as a possibility...

8/31/06
AIDS THERAPY: OBSTACLES ARE IMMENSE
Print Single-Page Save

By HAROLD M. SCHMECK JR.
Published: June 26, 1986
Despite the heartening success in restoring immune function in one AIDS patient by bone marrow transplantation from his twin, doctors would face formidible obstacles in trying that form of treatment on a broad scale against the disease.

Money and dedication could overcome some of these obstacles, but others depend on questions that are still unanswered by science and the art of medicine.

Transplants between unrelated people would be necessary if the technique were to make any major impact against acquired immune deficiency syndrome. But bone marrow transplants from donors unrelated to a patient are still highly experimental and the total number of such transplants has been minuscule compared with the number of AIDS cases.

A large increase in the number of marrow transplant patients would involve major expense, experts said, and it still remains to be proved that bone marrow transplantation can be effective when donor and recipient are unrelated. A Government study last year reported that fewer than 70 such transplants had been done altogether throughout the world and most of the patients lived only months afterward. None of these were done for AIDS. A Need for Caution Probably much that is valuable will be learned about AIDS through the present attempt, but Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, who reported the AIDS case at an international conference in Paris this week, emphasized the need for caution. He said there were no plans for widespread use of the treatment, which involves transplanting bone marrow, administering the antiviral drug suramin and transfusing white blood cells.

For the time being, he said, this therapy is contemplated only for AIDS patients who have identical twins. He also emphasized that the success in restoring the one patient's immune system has lasted only 10 months and that the treatment failed in two other patients.

Dr. Robert Peter Gale, of the University of California at Los Angeles, said his group has done four bone marrow transplants in gravely ill AIDS patients who have identical twins. The specialist said there was no unequivocal evidence of improvement. In collaboration with Dr. Fauci's group at the National Institutes of Health, Dr. Gale's group plans to do two more. In these cases, Dr. Gale said, a prior step will be the attempt to use drugs to eliminate all traces of AIDS virus from the patient before the transplant is done. Risks of Procedure

Experts estimate that about 1,000 bone marrow transplants are done each year in this country, most of them between relatives. In each case the patient must be protected rigorously against any infection for weeks afterward because he is extraordinarily vulnerable to microbes.

In addition, in cases other than transplants between identical twins, there is the risk that the cells of the transplanted marrow will attack the recipient's body as foreign. Such reactions are frequently fatal. There has been recent progress in reducing this risk by use of drugs and by removing the main cells that cause the reaction from the transplanted tissue. Some of these treatments, however, decrease the ability of the transplanted marrow to survive and prosper.

In contrast with the roughly 1,000 marrow transplants done every year, the Public Health Service estimates that there will be 26,000 AIDS patients alive in this country this year and that by 1991 this number will rise to 145,000.

The Government prediction is that there will be a cumulative total of 18,000 AIDS deaths in the United States by the end of this year. The cumulative death total from AIDS by 1991 is predicted at somewhere between 142,000 and 201,000.

The logistical and medical-scientific problems of using marrow transplants to make an inroad on this huge toll would be immense.

Dr. Robertson Parkman, a bone marrow transplant expert at Children's Hospital of Los Angeles, said the problems of facilities and supply of trained personnel could probably be overcome by a major effort like that mounted against polio before a vaccine was developed. Many Would Be Screened Because bone marrow transplantation is only feasible between persons whose tissue types match closely, large scale screening would be necessary to find donors for most AIDS patients. From studies on bone marrow transplantation for other purposes it has been estimated that only about 30 percent of patients are likely to have a close relative with suitable tissue.

Dr. C. Dean Buckner of the Fred Hutchinson Cancer Research Center in Seattle estimated that it is necessary to screen 10,000 persons to have a 50 percent chance of finding a suitable donor for any given patient.

Last year a Government panel headed by Dr. Brigid G. Leventhal of Johns Hopkins University considered the possibility of establishing a nationwide bone marrow registry to facilitate matching of potential donors with recipients. The panel concluded that local panels were more practical.

Dr. Leventhal explained yesterday that this was partly because the local panels can better stay informed on the status of all of its potential donors. She estimated that the tissue typing of a single patient or recipient costs $600 to $1,000. To multiply this by many thousands would involve an enormous investment for the tissue typing alone.