Inclusion Criteria:

1. Age ≥18 years, and

2. HIV infection, and

3. Antiretroviral-naïve, and

4. CD4+ T cell count >350 cells/mm3, and

5. Meeting one of the following criteria:

1. "Elite controllers": antiretroviral untreated with an undetectable (< 50 copies/mL)
viral load for at least 12 months (isolated blips up to 1,000 copies/mL allowed, but must
be preceded and followed by undetectable viral load), or 2. "Non-controllers":
antiretroviral untreated with a detectable (> 10,000 copies/mL) viral load, with the
intent to start antiretroviral drugs.

Exclusion criteria:

1. Persons with known rheumatologic conditions (e.g., systemic lupus erythematosus),
because of their predilection for biologic false-positive testing on HIV antibody
tests.

2. Screening absolute neutrophil count <1,000 cells/mm3, platelet count <70,000
cells/mm3, hemoglobin < 8 mg/dL, estimated creatinine clearance <40 mL/minute,
aspartate aminotransferase >100 units/L, alanine aminotransferase >100 units/L.

3. Screening genotype resistance testing showing resistance to tenofovir or
emtricitabine.

4. Known kidney disease.

5. Known bone disease, including pathologic fractures.

6. Patients with chronic Hepatitis B infection, because of the risk of liver
abnormalities after starting and stopping tenofovir/emtricitabine.

7. Concurrent treatment with lamivudine, adefovir, entecavir, or telbivudine.

8. Serious illness requiring hospitalization or parental antibiotics within the
preceding 3 months.

9. Any vaccination 2 weeks prior to baseline (Day 0) visit and throughout the study
period. NOTE: Because the study will most likely be actively recruiting during the
influenza season, all subjects will be encouraged to receive their annual influenza
vaccine at the screening visit (4 weeks prior to baseline [Day 0] visit) if they have
not already been vaccinated for the 2009-10 season and if it is medically indicated.

10. Concurrent treatment with immunomodulatory drugs, or exposure to any immunomodulatory
drug in the preceding 16 weeks (e.g. corticosteroid therapy equal to or exceeding a
dose of 15 mg/day of prednisone for more than 10 days, IL-2, interferon-alpha,
methotrexate, cancer chemotherapy). NOTE: Use of inhaled or nasal steroid use is not
exclusionary.

11. Concurrent treatment with phenobarbital, phenytoin, or rifampin.

12. Pregnant or breastfeeding women. Females of childbearing potential must have a
negative serum pregnancy test at screening and agree to use a double-barrier method
of contraception throughout the study period.