In HIV-positive people whose immune systems are weakened, treatment that inhibits the “IDO” protein does not interfere with combined antiretroviral therapy.
- A host-directed therapy, blocking or inhibiting an immune system protein called “IDO”, is approved by the FDA for use in cancer patients.
- In combination with antibiotics, the IDO inhibitor improves immune responses in the lung, leading to better control of tuberculosis.
- “There was no increase in viral load in animals receiving combined antiretroviral therapy and the IDO inhibitor,” according to the American researchers.
Globally, tuberculosis is the second leading cause of death from infectious diseases, behind Covid-19 and ahead of AIDS, according to the World Health Organization (WHO). Indeed, in 2022, 1.3 million people died from this infectious disease, generally pulmonary, caused by the bacteria Mycobacterium tuberculosis. Generally, many cases of tuberculosis can be controlled with months of antibiotics. However, the infection can come back in people who are immunocompromised due to HIV. “Research into host-directed therapies that attenuate immune activation is therefore needed”said researchers at the Texas Biomedical Research Institute.
Tuberculosis, HIV: a therapy inhibiting the “IDO” protein
This is why, in a study published in the journal JCI Insightresearchers examined a host-directed therapy that blocks or inhibits an immune system protein naturally found in the body. The protein in question is called “IDO (short for Indoleamine-2,3-dioxygenase)”. The latter normally suppresses the immune system, preventing it from causing excessive inflammation and organ damage. The IDO inhibitor is approved by the FDA for use in patients with cancer. According to several evidences, its inhibition for short periods of time has led to more effective cancer treatments. Thus, as part of the work, the scientists wanted to block or inhibit the protein in primates presenting both tuberculosis and the simian immunodeficiency virus, the non-human primate version of HIV.
Tuberculosis: “the inhibitor can be administered safely to HIV patients”
The results showed that therapy blocking or inhibiting the “IDO” protein improved immune responses in the lung, leading to better control of tuberculosis in combination with antibiotics. “There was no increase in viral load in animals that received the combination antiretroviral therapy and the IDO inhibitor, compared to animals that received the combination antiretroviral therapy alone, providing evidence that the inhibitor can be safely administered to HIV patients”, declared Smriti Mehraauthor of the study.
Now that the team has shown that the protein inhibitor “IDO” works well in combination with anti-tuberculosis antibiotics and with combined antiretroviral therapy separately, they plan to study its effectiveness when administered simultaneously in combination with the antibiotics and combined antiretroviral therapy. “Longer term studies are also needed to confirm that there are no unwanted side effects”said the researchers.
