<qa>  What is the primary hypothesis for HAART?Our primary hypothesis is that persons on D4TddIddCAZT containing highly active antiretroviral therapy HAART will demonstrate increased lactate production compared to HIV negative controls; that lactate metabolism will be normalized after treatment with cofactors riboflavin, thiamine, L-carnitine; that persons with liver disease on therapy will demonstrate prolonged lactate clearance; and that persons changed to a non-D4TddIddCAZT containing regime will demonstrate a decrease in lactate production from baseline. 