<qa>  What is a potentially life-threatening disease associated with treatment of chronic HIV infection?Lactic acidosis is a potentially life-threatening disease associated with the treatment of chronic HIV infection. Although acidosis is rare, hyperlactatemia is common and may have long term consequences yet to be recognized. Lactic acidosis is a manifestation of mitochondrial toxicity; consequences which have yet to be fully recognized and understood. In this study, we propose to look at lactate clearance and production by two methods, in four treatment groups, including HIV positive subjects on highly active antiretroviral therapy HAART treatment regimes and without HAART regimes, with liver steatosis and without, and compared with HIV negative controls. Supplementation with cofactors thiamine, niacin and L-carnitine, which may have a positive effect on lactate metabolism by facilitating mitochondrial function, will be studied as well. 