Friday, December 2, 2011

New Hope of a Cure for H.I.V.

                                  Medical researchers are now seeing that curing AIDS may be possible thanks to the positive outcomes of two patients. The article says that the first patient cleared his infection through bone marrow transplants. The second patient, a 50-year old man, although not yet cured, was able to briefly control the virus while being off of drug treatment by undergoing a a simpler gene therapy procedure. In the past, there have been attempts to cure HIV, however most experts found it more efficient to focus on prevention and treatment. Such treatment has effectively changed HIV from being a deadly disease to being a chronic disease. The treatment does not eliminate the disease, and if the infected patient were to stop taking the antiviral drugs, the virus would come "roaring back". Dr. Steven Deeks, professor of medicine at the University of California, San Francisco, said that he does not think the world has the resources to provide these daily drugs to the tens of millions of infected people for decades. Therefore a cure for the disease is becoming increasingly more vital. Grants totaling over $70 million are now being awarded to research teams with the intentions of finding a cure. It is expected to take years to find a cure, if at all, but it was said that they are closer to finding a cure than a vaccine.

There are two approaches being taken. The first being a sterilizing-cure, wiping out all traces of the virus from the body, like the first patient. The second being similar to the case of the 50-year old man, where the virus would not be eliminated but it would be possible to control the virus without taking the antiviral drugs daily.

The first patient's elimination of the cancer was circumstantial. While receiving bone-marrow transplants to treat his leukemia, he received an immune system resistant to the virus because the donor had lacked a protein, CCR5 which is on the surface of immune cells and is the entry point for the virus. This cleared the virus out of the patient's system. Bone marrow transplants are painful, risky, and expensive so this procedure could not be used as an ultimate cure. There is also the problem of finding immunologically matching donors and a donor with the rare mutation in the CCR5 gene. However, this case has built on the idea of finding a way to modify patient's immune cells to make them resistant to infection by eliminating CCR5.

This was what was done with the second patient. The man's white blood cells were treated with gene therapy to disrupt the CCR5 gene. A month later he was taken off his antiviral medication. The HIV in his blood shot up at first but by the end of 12 weeks fell down to an undetectable level again and his immune cell counts increased. His success might have been due to having an inherited mutation in one of his CCR5 genes already because the gene therapy did not work so well for 5 other patients. What was learned from the case however was that it could take freeing as little as 10 percent of the main immune cells infected by the HIV from the virus to control it since a vast majority of the patient's cells were not genetically altered.

There is currently being research and work done on disabling the CCR5 genes in blood stem cells. This would make the entire immune system resistant to the virus although it would require a stem cell transplant.

1 comment:

  1. It is amazing sometimes how scientific discoveries can be made unintentionally. When the patient recieved the bone marrow transplant, the purpose was not to cure the AIDs through recieving the immune system that lacked CCR5. However, the circumstances allowed for that to happen and led to further knowledge of how to defeat AIDs.