HIV (Human Immunodeficiency Virus) attacks the cells of the immune system, particularly CD4+ T lymphocytes, and replicates through them. Although the treatment for HIV, known as antiretroviral therapy, can control the infection, it does not completely eliminate the virus due to the presence of latent reservoirs, which are cells where the virus can remain hidden and inactive.

Macrophages are another type of immune cell that can also be infected by HIV. While the process of viral replication in macrophages is similar to that in CD4+ T lymphocytes, there are also differences due to the distinct structures of these cells.

To better understand how infected macrophages influence the amount of virus in the body during antiretroviral therapy, we developed a mathematical model. This model simulates HIV infection in two types of immune cells: CD4+ T lymphocytes and macrophages. It also accounts for two modes of viral transmission: direct cell-to-cell transmission and the transmission of free virus to a cell.

Through the study of this model, we found that while macrophages, when infected, are more resistant than infected CD4+ T lymphocytes, they contribute to the persistence of the virus in the body even during treatment. This indicates that it is crucial to consider macrophages when developing new treatment strategies against HIV.