Experimental AIDS Treatment Is Due
Researchers at the National Institutes of Health have discovered how the AIDS virus makes patients vulnerable to cancer and various infectious diseases that eventually lead to death in most cases.
In a report published in today’s New England Journal of Medicine, the scientists said the AIDS virus causes a subgroup of cells in the immune system to become defective in their ability to recognize viruses and foreign substances, such as cancer cells.
“We don’t know if the defect is that the cells can’t identify (the foreign invaders) or what, but we do know that the cell responsible for recognizing (them) is either absent or not functioning well,†Dr. Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases, said in a telephone interview.
Fauci is one of six scientists who authored the report. Dr. H. Clifford Lane of the Institute of Allergy and Infectious Diseases is principal author.
Fauci said the new finding opens the way for an experimental treatment that will begin soon at his institute in Bethesda, Md., employing bone marrow transplants to reconstitute the defective cells.
When the AIDS virus infects an individual, it invades a key group of cells in the immune system called T-cells. A subgroup of T-cells called helper/inducer lymphocytes are responsible for the induction and regulation of a major part of the immune system’s armamentarium of defense weapons, such as the release of chemicals like interferon.
These cells accomplish those tasks after first recognizing the presence of the foreign invaders. This is done by identifying specific proteins, called antigens, on the invaders’ surface.
Once that is done, the helper/inducer cells immediately begin proliferating, and a chain of events is triggered that brings into play other elements of the immune system that normally results in the destruction of the invaders.
But in patients with acquired immune deficiency syndrome, the researchers found that the helper/inducer cells fail to take the first step of recognizing specific antigens that identify the foreign invader. As a result, the rest of the chain of events falters, and the defense system breaks down.
The scientists showed in a series of experiments that the rest of the defense system is capable of working if the initial recognition of an enemy occurs.
Several years ago the government researchers tried doing bone marrow transplants on AIDS patients, but the transplants were unsuccessful because the researchers did not realize that the virus continued to destroy T-cells, Fauci said.
The plan now, he said, is to do a bone marrow transplant and at the same time to treat the patient with an experimental antiviral drug called suramin, which has been shown to inactivate the AIDS virus in the laboratory.
