n July 2008, a headline appeared in newspapers around the world heralding a scientific finding that seemed like it might revolutionize our understanding of racial disparities in HIV prevalence. A team of British and American scientists were reporting that an anti-malaria gene common only in blacks increased the risk of HIV infection 40 percent. The researchers added that if the gene variant weren’t present in sub-Saharan Africa, the region would likely see an 11 percent decrease in HIV.
It wasn’t great news, implying as it did that blacks had some genetic weakness that makes us particularly vulnerable to the disease. But the findings at least seemed to indicate that scientists were actually making progress. The problem is that less than a year later, at least four studies had refuted them and no studies had replicated them. And no media organizations bothered to update the story, the biggest in HIV research in years. So when we read yesterday in The New York Times that some scientists are hopeful there will be a cure for HIV, a question well worth asking was, ‘If there is a cure, will it work for us?’ In preparation for World AIDS Day, we’re going to get a lot of stories that talk about HIV, without talking specifically about us.
Scientists have long known that some black people are highly resistant to HIV. A 1996 article published in Lancet reported that 43 of the 424 Nairobi, Kenya prostitutes who participated in a study between 1986-1994 did not contract HIV-1 during the study, for at least three years, despite their repeated unsafe exposure to the virus. Almost 15 years later, very little is known about how such people resist the disease. The vast majority of HIV-1 genetic studies have focused on people of Western European ancestry, even as in the US African-Americans accounted for 44 percent of all new HIV infections in 2009. So it’s not surprising that, as of October 2010, the only thing that scientists knew for certain about the genetic risk factors for HIV-1 relates to Europeans. Scientists found that the 1 percent of Europeans born without CCR5, a protein that acts as a receptor for HIV-1 viruses, are completely resistant to HIV-1.
So far, that discovery has helped two people. A white San Francisco man has been HIV-free for about four years, after he got two bone marrow transplants from a donor without the CCR5 gene. A Trenton, New Jersey man — who told the Times he wished to remain anonymous — saw his viral load become undetectable after he received a gene therapy treatment that reduced the number of CCR5 genes in his body, the Times reports. Fortunately for him, “he had an inherited mutation in one of his two CCR5 genes, making the job easier for the gene therapy,” the paper reports. In five other gene therapy recipients, the treatment has failed.
The philosophy behind the search for genetic risk factors is that identifying them might help scientists find a cure or improve the treatment and their CCR5 discovery may still help them do that. But as World AIDS Day approaches, the best discoveries that scientists have made regarding HIV in Africa remain related to prevention. Three clinical trials have shown that the circumcision of heterosexual southern and eastern African men reduces their risk of acquiring HIV by 54% over a two year period, compared with uncircumcised men.
African-Americans haven’t had a real breakthrough like that since the advent of today’s anti-retroviral HIV treatment. Still there’s good reason to hope that more discoveries leading to a cure for everyone are in the pipeline. With advances in human genome mapping, scientists have recently developed a detailed description of how genetic variation influences the body’s ability to control HIV-1. Let’s hope that more of us get involved in the HIV genetics research necessary to create the cure, as study participants and as researchers, even as we continue fighting for the equitable distribution of treatment.