Cancer immunotherapy effectively fights HIV reservoirs

A group of specialists from the Montreal University Hospital Research Center (CRCHUM) showed that cancer immunotherapy can reduce the level of HIV in the body of PLHIV if the latter are taking triple therapy. Scientists have determined how this treatment method can detect the virus in hidden tanks and make it vulnerable to the immune system. The results were published this week in the journal Nature Communications.

“We have identified the mechanism by which anti-cancer immunotherapy in people receiving a triple dose,“ lures ”the virus out of“ shelters ”and reduces the size of HIV reservoirs. Although most of our experiments were performed in vitro, our approach may lead to the development of new treatments, ”said Dr. Nicholas Shomon, CRCHUM specialist.

HIV reservoirs are the cells and tissues in which the virus persists despite the patient's receiving ARV therapy. The treatment prevents the development of infection in acquired immunodeficiency syndrome (AIDS), but is not able to completely defeat the virus. In order to survive and intensify at the moment of insufficient concentration of ART, HIV creates so-called reservoirs. To do this, it usually infects CD4 + T-lymphocytes and white blood cells, which are responsible for the activation of immunity. At the same time, being in a latent state, HIV remains invisible to the protective mechanisms of a person.

Remaining to be the subject of intensive research, reservoirs are the last obstacle to the eradication of the virus and force people living with HIV to take antiretroviral drugs for the rest of their lives.

In 2016, Dr. Remy Fromentin, a researcher at the laboratory of Professor Nicholas Shomon, showed that the cells in which persistent viruses are stored have specific immunological characteristics: three proteins, called PD-1, LAG-3 and TIGIT, are often expressed on their surface . Today, these molecules are targets of immunotherapy used in the treatment of cancer. Experts decided to evaluate the effect of these methods on HIV reservoirs.

“Our results prove that immunotherapy targeting molecules, particularly PD-1, can reduce the level of virus persisting in people receiving triple therapy. One of the next steps could be the combination of immunotherapy with molecules that have so far been ineffective in combating HIV reservoirs. This combination of immunotherapy and chemical molecules can “awaken” the virus and help destroy HIV-infected cells, ”added Professor Chomont, who also participated in the study and presented data from one of the patients who received immunotherapy for melanoma.

“The size of the patient’s HIV reservoirs has decreased significantly, which is encouraging. However, we must be careful in our assessments, because this does not work with all patients. These procedures also cause significant side effects, ”said Dr. Fromentin.