Human immunodeficiency virus (HIV)-infection and treatment with antiretroviral therapies are associated with several cardiometabolic risk factors; insulin resistance, diabetes, dyslipidemia, central adiposity, that increase risk for MI and stroke. A new class of drugs used to treat type 2 diabetes has been introduced; Dipeptidyl peptidase-IV (DPPIV)-inhibitors (Januvia®, Onglyza®, alogliptin). Dipeptidyl peptidase-IV (DPPIV)-inhibition could be a safe and effective therapy for HIV-associated insulin resistance and diabetes. However, no safety data exist. The research question is: If HIV+ adults with stable immunologic (CD4+ T-cell count >350 cells/μL) and virologic (plasma HIV RNA <50 copies/mL) function are given a DPPIV-inhibitor would their CD4+ T-cell count and plasma HIV RNA level increase, decrease, or stay the same? Theoretically, DPPIV-inhibition could enhance their immune system by increasing SDF-1α levels; a potent inhibitor of HIV-entry into T-cells, or harm the HIV+ immune system by inactivating CD26 on immune cells. We hypothesize that DPPIV-inhibition will not harm the immune system in HIV+ people. We propose a blinded randomized controlled pilot safety trial of an FDA-approved DPPIV-inhibitor in virologically- and immunologically-stable HIV+ men and women. We will monitor CD4+ T-cell count, plasma HIV RNA levels, immune activation markers, and safety outcomes (lipid/lipoprotein profiles, blood pressure, kidney and liver function) during 4-6 months of DPPIV-inhibitor exposure vs placebo in 20 HIV+ adults. If safety is confirmed, the efficacy of DPPIV-inhibition in HIV+ with insulin resistance will be tested in future trials that examine potential glucoregulatory and cardiovascular benefits.