Cancer Therapies Give Hope to HIV Cure Research, but Access Is Limited

Scientists attempting to find an HIV cure have turned their attention to progress made in cancer therapy research and development in recent years. Cancer "immunotherapies" are agents that change immune system functioning in order to clear foreign, cancerous cells from the body. HIV researchers speculate that these same agents may be useful in helping the immune system clear HIV-infected "reservoir" cells that linger even in the body even with successful antiretroviral therapy. Research progress is dependent, however, on pharmaceutical companies that develop immunotherapy drugs investing in HIV cure research instead of -- or in addition to -- cancer research.

Steven Deeks, M.D. (Credit: UCSF)
Steven Deeks, M.D.

"We believe -- in our large virtual family of [HIV] cure researchers -- that enhancing T-cell function may in fact contribute to an HIV cure," said Steven Deeks, M.D., professor of medicine in residence at the University of California, San Francisco. "It's our hope that immunotherapy -- as it becomes well-characterized in the context of cancer including how to manage its toxicity -- we will be able to, in a few years, translate it to the context of HIV infection."

HIV-infected CD4 cells and cancerous cells manipulate similar chemical pathways to suppress immune system responses designed to rid the body of infected or foreign cells.

"There are multiple pathways where the immune system can 'turn itself off,'" explained Deeks. Infected cells trigger an inflammatory response by the immune system which is typically only turned off -- through a dominating anti-inflammatory response -- after the infected cell is killed. Deeks likened this anti-inflammatory response to the brakes being applied in a car.

Cancer and HIV evade the immune system's healing inflammatory response by applying the brakes early. This leads to what's called immunosuppression -- with the release of inflammatory markers like IL-10, PD-1, and CTLA-4. The "inflammation" that HIV researchers and clinicians talk about when they discuss chronic HIV disease and its detrimental effects on the heart and other organ systems, is actually a chronic state of immunosuppression -- the brakes of our immune system being applied too early and too often.

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