March 17, 2009
Hair strands might help determine the effectiveness of antiretroviral drugs for HIV-positive people, researchers from the University of California-San Francisco said recently, VOA News reports. Monica Gandhi of the university and colleagues have found that antiretroviral levels in hair samples strongly correlate with HIV levels in patients. They also found that the hair samples can indicate which medications are being used well and which are not, as well as if patients are taking adequate doses. According to VOA News, because hair grows at a specific rate -- about one centimeter monthly -- these tests can provide an average reading of how well drug therapy is working. "We collect a small sample of hair from the back of their head, and by small I mean 10 to 15 strands," Gandhi said, adding, "So we collect after about a month of therapy a small thatch of hair from the back of your head and then grind it up and measure the antiretroviral [levels] in that hair. And that gives us an idea after you start a new regimen whether you have enough in your system."
According to Gandhi, asking patients themselves for information about their drug regiments can have inherent issues. "We often ask the patient what is their adherence to their medication," she said, adding that physicians ask, "How much are they taking of their medication when we're trying to predict why they're not doing well. And self-reported adherence has its own set of limitations. There's, you know, bias in how people present their level of adherence and there's literally just memory problems in people not remembering how much they're taking." In addition, blood samples to test antiretroviral levels can present problems, according to Gandhi. "The problem there was everyone's blood levels of drugs varies day by day," she said, adding, "So depending on what I ate for breakfast that morning or if I smoked that morning or if I took another medication that interfered, the levels are sort of going to be up and down every day."
Although some hairs are useful for testing, others are not, according to Gandhi. "We have tested it on all types of hair, African hair," she said, adding, "We actually have some projects in Uganda with African hair. It works on fine hair. It works on gray hair. One thing is that people ask can we use pubic hair for these measurements. And we don't' think that those are going to be useful because hair in those areas grow to a certain length and then they stop. ... But you really want to measure hair that's sort of growing continuously and that's really scalp hair."
Reprinted with permission from kaisernetwork.org. You can view the entire Kaiser Daily HIV/AIDS Report, search the archives, or sign up for email delivery at www.kaisernetwork.org/dailyreports/hiv. The Kaiser Daily HIV/AIDS Report is published for kaisernetwork.org, a free service of the Kaiser Family Foundation, by The Advisory Board Company. © 2009 by The Advisory Board Company and Kaiser Family Foundation. All rights reserved.