 This research study is being done to find out how the immune system in the small intestines improves after taking antiretroviral anti-HIV medications. Biopsies small snips of tissue will be taken from the part of the intestines just below the stomach, and will be studied in the laboratory. The main purpose of this study is to measure the increase in the numbers of immune cells in the intestines to see if this number is related to the amount of medication that reaches the intestinal tissue, and the amount of virus that is still hiding there. 