A new defense against human immunodeﬁciency virus may have appeared in the form of drugs ordinarily used to prevent the rejection of transplanted organs, according to a new study.
Currently, antiretroviral drugs are used to manage human immunodeﬁciency virus (HIV). These drugs prevent the virus from replicating and damage from occurring to the immune system. But antiretrovirals must be taken for life, and they are expensive and may have side effects.
Consequently, experimental research is now looking at alternative strategies to manage, prevent and possibly even cure HIV.
Medical News Today has previously reported on studies looking at a potential radioimmunotherapy cure for HIV, as well as the case of a "functional cure" in a baby receiving aggressive antiretroviral therapy.
The new study - by researchers at the University of California, San Francisco and published in the American Journal of Transplantation - also refers to research from 2009 that seemed to find a working cure in one person by using a hematopoietic stem cell transplant.
"Current therapies fail to cure the disease as they do not attack those viruses that remain hidden within the immune system," says Dr. Steven Deeks, who led the new research.
These "hidden" viruses seem to be sustained by inflammation in the body caused by the HIV infection. Dr. Deeks' team wondered if they could use immunosuppressant therapy to reduce inflammation and create an inhospitable environment for the virus.
Kidney transplant patients who have HIV were monitored by the researchers
The participants who took an immunosuppressant called sirolimus had fewer HIV-infected blood cells over time.
The team followed 91 kidney transplant recipients with HIV for an average of 3.2 years after having their transplants.
Analyzing blood samples from these patients, the researchers found that HIV was well controlled during the long-term exposure to immunosuppressive drugs.
In particular, the participants who took an immunosuppressant called sirolimus had fewer blood cells infected with HIV over time.
Sirolimus works by modifying the behavior of T cells, and some T cell functions are implicated in two of the main four factors that are thought to contribute to HIV persistence.
"Based on the observations in this study, the NIH [National Institutes of Health] is now sponsoring a targeted study to see if sirolimus might indeed contribute to a cure of HIV infection," says Dr. Deeks.
By looking at the limitations to their own study, Dr. Deeks and his team are also able to outline further areas of study for how sirolimus might be able to limit HIV persistence.
These include taking biological specimens and using different techniques to measure the level of HIV that is able to replicate. The team also wondered if the fact that all of their participants had kidney transplants might have also influenced the results.
Despite this, Dr. Deeks is satisfied that their study reports the findings of a controlled clinical trial supporting the use of sirolimus on HIV persistence. He concludes:
"Our study highlights the potential synergies that can occur when two very different disciplines merge their talents and resources. We feel that the transplant community has much to teach the HIV community about the potential role of strong immune-suppressing drugs in curing HIV disease."