Patients who have been infected with HIV recently are considered to have acute, or early, HIV infection. During this period, viral load (level of HIV in the body) rises sharply to a high level at first but then decreases significantly on its own. Doctors are not sure why this decrease in viral load happens and how the body is able to accomplish this. In this study, patients with acute HIV infection will be monitored so that doctors can study their immune systems to try to learn more about this rise and fall in viral load.