Is Anyone Immune to HIV?

Timothy Ray Brown

Even the most careful individuals can find themselves with a positive HIV diagnosis, while others couldn’t get the disease if they tried. Researchers are trying to find out why some people carry a genetic mutation that makes them highly resistant to HIV infection. This mutation, called Delta32, keeps a protein called CCR5 from rising to the surface of the immune system’s T cells. When CCR5 is on the surface of the cell, HIV is able to latch on to it and infect the cell; when it is not, the cell’s “door” is effectively closed to HIV.

Very few people have this genetic variation, which some scientists think has been inherited from ancestors who survived the massive bubonic plague in Europe centuries ago. About 1% of Caucasians have it, and it is even rarer in Native Americans, Asians, and Africans. A 2005 report indicated that 1% of people descended from Northern Europe are virtually immune to AIDS.

Those lucky enough to be resistant must inherit the HIV-shielding genes from both parents, though having only one parent with the mutation still leaves a child better prepared to defend HIV than having none. At least one genetic testing company, still does the HIV immunity test (among their battery of tests, not as a stand alone), though many companies that once catered specifically to gay men for the HIV immunity test have closed down.

In the case of Timothy Ray Brown, the so-called Berlin patient cleared of HIV after receiving stem cell transplants to treat his leukemia, there was great difficulty finding a donor who not only had this mutation, but matched other components of Brown’s immune system closely enough that his body would not reject the cells. Researchers are now focusing on the possibility of introducing the rare genetic mutation into a patient’s body, infusing T-cells that have been modified so as to have the CCR5 variation.

Under the sponsorship of the National Institutes of Health, researchers at the University of Pennsylvania Perelman School of Medicine in Philadelphia, the Fred Hutchinson Cancer Research Center in Seattle, and other institutions and biomedical companies are conducting research on this process, first to assess its safety, then its effectiveness. The latter will involve stopping study participants’ anti-HIV medications to see if their immune systems continue to suppress the virus.

Joining in such research will be the Timothy Ray Brown Foundation, which Brown has formed in partnership with the World AIDS Institute. “The Timothy Ray Brown Foundation will be solely dedicated to finding a cure for AIDS,” Brown said at the U.N. AIDS conference in July.
Since this article originally ran in 2012, Timothy Ray Brown, the “Berlin Patient”, who was apparently cured of his HIV status has served as an advocate for bringing a cure to others who have been infected with HIV. However, a recent interview with Brown, as well as the doctor who cured him, has served to underscore how much of a role luck played in curing Brown of his diagnosis.

Brown’s doctor, Gero Hütter, pointed out that Brown was in the “right place at the right time”. Efforts by doctors to succeed in curing other patients using Hütter’s treatment method have been unsuccessful, with patients dying from the stem cell transplant itself, or other complications before it could be determined if HIV had been removed from the patient’s bodies.

That said, the groundwork laid down by Hütter in curing Brown of HIV is now viewed as the blueprint for the cure to HIV. The consortium of academic and private sector research institutions of defeatHIV — a Delaney Cell and Genome Engineering Initiative — are hoping to use stem cells from HIV-positive individuals to mimic the genetics of humans immune to HIV. Clinical trials are now opening up within the consortium for patients who meet multiple eligibility factors.

It may be a while until we can find a cure to HIV, but, it seems that there is real possibility down the path of the Berlin Patient. The possibility is enough to excite researchers into seriously pursuing further results, which should excite those who live with HIV. There might, indeed, be a light at the end of the tunnel. How soon they find it, though, is still very much up in the air.

Tags: Prevention