This laboratory-based sub-study of ATN 061 and ATN 071 will examine the effect of early treatment followed by treatment de-intensification to atazanavir/ritonavir (ATV/r) monotherapy on steady-state frequencies of replication-competent CD4+ T cell Human Immunodeficiency Virus (HIV)-1 reservoirs or cell-associated infectivity (CAI) and persistent low-level viremia (LLV), and their contribution to successful long-term control of HIV-1 replication among HIV-1 infected adolescents and young adults.

081 participants must first be enrolled in either ATN 061 or ATN 071 and meet the eligibility criteria of those protocols in addition to those below.

Inclusion Criteria:

061 Participants

• Currently on treatment with an ATV/r-based HAART regimen (ATV/r, FTC, TDF is the preferred regimen);

• HIV-1 viral load < 100 copies at week 24;

• CD4+ T cell count > 350 cells/mm3 at week 24; and

• Able to provide informed consent for the sub-study and adhere to the protocol.

  071 Participants

• Initiated HAART according to current DHHS guidelines (CD4+ T cells < 350 cells/ mm3);

• Currently on treatment with a PI-containing HAART regimen; subjects taking a protease inhibitor OTHER than ATV/r must receive approval by the team via the ATN QNS;

• Plasma HIV-1 viral load < 100 copies at week 24 on HAART; measurement to be collected from clinical care results contained in the medical record at the clinical site within +/- 30 days of week 24 on therapy;

• CD4+ T cell count > 350 cells/mm3 at week 24 on HAART; measurement to be collected from clinical care results contained in the medical record at the clinical site within +/- 30 days of week 24 on therapy; and

• Able to provide informed consent for the sub-study and adhere to the protocol.

General Exclusion Criteria:

• Currently enrolled in the Standard Care Arm of ATN 061;

• Pregnancy or breast feeding;

• Severe (Grade ≥ 3) anemia or other conditions that would not allow adequate blood volume to be drawn;

• Active treatment for systemic infections;

• Treatment with immune modulators, including immunosuppressive or immune modulating therapy (IL-2, intravenous gammaglobulin, and therapeutic or other experimental vaccines including HIV-1 vaccine given for primary prevention at any time (short courses (<14 days) of prednisone for reactive airway disease (RAD) are permitted);

• Active hepatitis B infection as defined by Hepatitis B antigen (Ag) positive;

• Disallowed Medications (see Section 5.3.2);

• Active drug or alcohol use or dependence that, in the opinion of the site personnel, would interfere with adherence to the study; or

• History of chronic renal insufficiency or Grade 3 or greater serum creatinine.

  061-Specific Exclusion Criteria

• History of an Acquired Immunodeficiency Syndrome (AIDS)-defining illness;

• Meets any ATN 061 exclusion criteria for de-intensification; or

• Meets any ATN 061 premature study discontinuation criteria.

  071-Specific Exclusion Criteria: None

Twenty-five subjects enrolled in Arm A of ATN 061 who started highly-active antiretroviral therapy (HAART) at CD4+ T cells > 350 cells/cubic millimeter (mm3) and are undergoing treatment de-intensification at week 48 of HAART.

Twenty-five "control" subjects initiating HAART based on current Department of Health and Human Services (DHHS) guidelines at CD4+ T cell levels < 350 cells/mm3 and maintained on standard HAART.