2024-01-23 18:00:09
Truvada antiretroviral pills, in San Anselmo (United States), November 23, 2010. JUSTIN SULLIVAN/GETTY IMAGES/AFP
Diagnose HIV infections as early as possible, to treat them as quickly as possible. A study published on January 11 in the journal Nature Communications provides a strong argument in favor of this strategy. Because, beyond the collective interest – stopping the chain of contamination – the benefit is also individual. Early antiretroviral treatment, this work shows, promotes a lasting immune response, capable of neutralizing the virus even after stopping treatment. Carried out on macaques, the study was carried out by teams from the Institut Pasteur (Paris), the CEA and Inserm (Paris-Saclay University).
Enough to better understand a phenomenon observed in the 2000s in a small group of patients, the “post-treatment controllers”. In France, thirty-one of them are followed within the Visconti cohort. They benefited early from a combination of antiretrovirals, the famous triple therapy (for 80%, within three months after the primary infection), which they followed for several years (three or four years, median duration) . Even though they stopped taking their medications, the virus remained undetectable in their blood for up to twenty-three years after stopping, the median duration of follow-up being fourteen years. A very rare phenomenon: in the vast majority of cases, as soon as a patient interrupts their antiretroviral therapy, HIV multiplies again and the disease progresses.
How to explain this control of the virus? In 2013, the importance of starting treatment – triple therapy – very early was raised. It remained to be formally proven. The authors compared three groups of macaques infected with SIV, simian immunodeficiency virus. This model allows control of other parameters (sex, age, genetic background, strain of the virus, etc.) likely to modify immune responses and progression to the disease.
Educate the immune response
The first group (11 animals) received standard triple therapy four weeks after infection (acute phase). The second (11 animals) started this same treatment six months after infection (chronic phase). In both cases, treatment was discontinued after two years. As for the third group (17 animals), it was not treated.
Results: 9 of the 11 macaques treated early controlled the multiplication of the virus in the blood, compared to only 2 of the 11 monkeys treated late and 2 of the 17 untreated. “Early treatment greatly increased the probability of viral control after treatment interruption”, summarizes Asier Saez-Cirion, from the Pasteur Institute in Paris, who coordinated the study with Roger Le Grand, from the University of Paris-Saclay (CEA, Inserm). If treatment is started five months later, the “window of opportunity” has passed.
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