AIDS Virus May Hide in the Gut, Study Finds
October 20, 2006
HIV replicates in the lining of the gut and wreaks havoc on the immune system there, Satya Dandekar, chairperson of the Department of Medical Microbiology and Immunology at the University of California-Davis Health System, and colleagues recently reported. According to Dandekar, the study is the first to explain why highly active antiretroviral therapy (HAART) cocktails often fail to work completely.
"The real battle between the virus and exposed individuals is happening in the gut immediately after viral infection," Dandekar said. "We need to focus our efforts on improving treatment of gut mucosa, where massive destruction of immune cells is occurring. Gut-associated lymphoid tissue accounts for 70 percent of the body's immune system. Restoring its function is crucial to ridding the body of the virus."
Dandekar's team has been studying how HIV patients, even those not undergoing treatment, have survived at least 10 years with healthy immune systems, including T-cells targeted by HIV. "We looked at their gut lymphoid tissue and did not see loss of T-cells there," said Dandekar. "This correlated with better clinical outcomes."
In the current study, the researchers followed 10 patients undergoing HAART treatment, taking blood and gut samples at baseline and after three years of therapy. What they found was evidence of inflammation, which impairs tissue function, promotes cell death, and destabilizes the normal balance of gut bacteria.
"We found a substantial delay in the time it takes to restore the gut mucosal immune system in those with chronic infections," Dandekar reported. "In these patients the gut is acting as a viral reservoir that keeps us from ridding patients of the virus."
The researchers said the findings suggest anti-inflammatory drugs could enhance the efficacy of HAART.
The study, "Viral Suppression and Immune Restoration in the Gastrointestinal Mucosa of Human Immunodeficiency Virus Type 1-Infected Patients Initiating Therapy During Primary or Chronic Infection," was published in the Journal of Virology (2006;80(16):8236-8247).
This article was provided by CDC National Prevention Information Network. It is a part of the publication CDC HIV/Hepatitis/STD/TB Prevention News Update.