*Objectives: Primary objective of the study is the evaluation of the effect of MMF on the chronic hyperactivation of the immune system and the decrease of the CD4+ T-cell count in chronically HIV-1 infected patients who are not treated with antiretroviral therapy (ART). Secondary objectives include the evaluation of the effect of MMF on plasma HIV-1 RNA; progression of disease/ reaching of indication to start ART; and the safety of treatment with MMF in this patient group.