This protocol is a study of HIV+ young people who were identified as having certain HIV-1 specific T-cell responses and genetic markers while previously enrolled in the 5-year longitudinal adolescent study, "REACH." Blood samples will be collected, a medical and medication history and physical examination will be performed every 6 months for a total of 2 years.

Numerous studies have demonstrated an association between HLA class I genotypes with differing progression to AIDS in individuals who are followed after being off antiretroviral therapy. These studies do not always associate the same HLA class I alleles with the risks of HIV-1 disease progression; however they consistently demonstrated that HLA-B*35 and B*53 portend a bad outcome compared to the better outcome observed in HLA-B*27 and B*57 carriers. Despite this information, very little data exists to explain the mechanism of this association.

This longitudinal study will look at the HIV-1 specific CD8+ T-cell responses and the dominant HIV-1 genotype among individuals identified as HLA-B*27, B*35, B*53 and B*57 positive through studies done in collaboration with the REACH project.

Inclusion Criteria:

• HLA-Class I HLA-B*27, B*35, B*53 and/or B*57 positive identified through the REACH study
• Subject's ability and willingness to provide written informed consent
• Subject's ability and willingness to be followed at least one year on this ATN 026 study

Exclusion Criteria:

• On chronic immunosuppressive therapy, not including topical or inhaled steroid use.
• Any prohibited medication listed in protocol within 2 weeks prior to the Entry visit labs

Subjects who were identified as HLA Class I HLA-B*27, B*35, B*53, and/or B*57 positive from the REACH study will be contacted for their interest in participating in this study. Only former REACH sites in the ATN will be eligible to enroll subjects into this study.