Number of CD4 cells and early treatment affects volume of HIV reservoirs

Experts believe that people with HIV who start antiretroviral treatment before they develop extensive immune system damage will end up with a smaller HIV reservoir in the long run - something that in turn can improve effectiveness of treatment and the quality of life of people living with HIV. Data was presented this week at the 11th International Scientific Conference on HIV (IAS 2021).

Antiretroviral therapy (ART) blocks or slows the HIV replication cycle, but they are unable to eliminate the reservoirs created by the virus which can resume HIV production if treatment is stopped. The longer the virus remains unsuppressed the more it damages the immune system and the more reservoirs develop. This is one of the biggest barriers to an effective and safe HIV cure.

Professor Edwin Wright of the University of Melbourne and an international team of colleagues examined the relationship between the number of CD4-T cells and the size of viral reservoirs in people who initiated ART early in their infection.

According to previous studies, people who started treatment with CD4 levels 500 cells/mm3, or higher, had a significantly lower risk of underlying illness and death than those who waited for their CD4 count to fall below 350. 

The results of these previous studies have led to a change in global HIV treatment recommendations, recommendations that now suggest that ART to be prescribed to all diagnosed with HIV, regardless of their CD4 count.

In an additional study, a team of researchers led by Professor Wright compared the size of the viral reservoir in people who began treatment with differing CD4 counts.

Experts divided the participants into 3 groups depending on their "starting" CD4 count:

• Group 1: CD4 count 500-599 (36 people)
• Group 2: CD4 count 600-799 (60 people)
• Group 3: CD4 count >800 (50 people)

The trial found that the volume of HIV reservoirs was lower in people who started treatment with a CD4 count above 800 compared to the other groups.

Researchers also noted that older men and women had lower overall HIV DNA levels than those of young people, but the link between lower total DNA and higher CD4 at the beginning of ART was confirmed.

Previous research from Germany demonstrated that initiating ART early also accelerated the decrease in viral load and, as a result, lowered the overall load on the body. This reduced the risk of HIV-related mortality and morbidity.