Regulatory T cells prevent liver fibrosis during HIV type 1 infection in a humanized mouse model.

Human immunodeficiency virus type 1 (HIV-1) disease is associated with aberrant immune activation, and coinfection with hepatitis C virus (HCV) exacerbates hepatic inflammation and fibrosis. However, the role of HIV-1 infection or host immune modulation in liver pathogenesis is not clearly defined. Here, we report that regulatory T (Treg) cells prevent liver immunopathogenesis during HIV-1 infection in a humanized mouse model. In the absence of Treg cells, HIV-1 infection induced liver fibrosis associated with hepatic stellate cell activation, hepatitis, and liver injury. Our findings provide new insight linking Treg cells and liver immunopathogenesis during HIV-1 infection.