Final answer:
The potentially life-threatening complication from HAART is lactic acidosis.
Step-by-step explanation:
The potential life-threatening complication from HAART (Highly Active Antiretroviral Therapy) is lactic acidosis. Lactic acidosis is a condition in which there is an excess of lactic acid in the blood. It can occur as a rare side effect of certain antiretroviral medications used to treat HIV/AIDS, including HAART.