February 12, 2014
This article was reported by Healio.
Healio reported on a study to determine why antiretrovirals (ARVs) are effective for treating HIV infection, allowing patients to live longer, but do not cure the infection.
The study by Timothy Schacker, MD, director of the program in HIV medicine at the University of Minnesota, and colleagues studied 12 patients who were treated with ARVs. Two patients had stopped treatment for more than a year and 10 patients had never taken ARVs prior the study. Participants received different types of ARVs: six of the patients received tenofovir-emtricitabine-efavirenz (Atripla); four received atazanavir (Reyataz) and ritonavir (Norvir); and two received darunavir (Prezista) and ritonavir.
The researchers then examined intracellular concentrations of ARVs using samples taken from the patients' lymph nodes, ileum, and rectum, as well as peripheral blood. Results show that ARVs were less likely to gain entrance to lymphoid tissue cells than peripheral blood cells. Findings indicate that virus production continued in some individuals' lymphatic tissues while they are receiving ARVs, due to a lower concentration of ARVs in lymphatic tissues compared to blood.
Ashley Haase, MD, of the University of Minnesota, commented that "most HIV replicates in the lymph and gut tissues"; therefore, researchers need to examine these tissues to determine drug efficacy. Haase also contended that the low-level replication found may be the cause of the "chronic immune activation" in some patients and may be related to accelerated, increased cardiovascular events and early mortality in some patients.
The full report, "Persistent HIV-1 Replication is Associated with Lower Antiretroviral Drug Concentrations in Lymphatic Tissues," was published online in the journal Proceedings of the National Academy of Sciences of the United States of America (2014; doi: 10.1073/pnas.1318249111).