Researchers at Johns Hopkins have concluded that sudden, temporary spikes in the amount of HIV in the body, commonly called blips, do not always mean the virus is developing resistance to AIDS drugs.
Today's anti-HIV drug treatments quickly suppress the virus to nearly undetectable levels, but blips are a frequent problem. Earlier studies suggested that blips occur in 11 percent of patients, while the Hopkins study, which used intensive sampling, found blips in nine-tenths of patients.
HIV-positive patients in the United States currently taking drug therapy, called highly active anti-retroviral therapy, or HAART,can be reassured that their medication has not failed," says senior study author and infectious disease specialist Robert Siliciano, M.D., Ph.D., a professor at The Johns Hopkins University School of Medicine and a Howard Hughes Medical Institute investigator. "Physicians and patients now have a much better idea of when to worry about these blips and when not to worry."
HIV mutates very rapidly and physicians and patients have worried that even small, temporary increases in the amount of virus could indicate the virus had mutated to evade anti-viral drugs being taken.
The Hopkins team has shown that these so-called blips are variations, that stem from the test used to gauge the amount of virus in the body, a measurement known as viral load.
Their findings show that unless the blip persists upon repeated testing, it does not imply that the virus has mutated, or changed form.
Changes in therapy to cope with drug resistance can be very difficult for the patient,says Siliciano. Different combinations of medications can have toxic side effects, and can be even harder to tolerate than the originally prescribed drug cocktail.
To check for possible mutation, the Hopkins team conducted a detailed genetic analysis of multiple blood samples from 10 HIV-positive patients,they took samples every two to three days over a period of three months between June 2003 and February 2004. All patients had their infection under long-term control, on HAART, and with viral loads of less than 50 copies per milliliter for at least six months.
36 blood samples were taken from each patient in total.