Raltegravir Intensification in HIV-infected Patients

Inclusion Criteria: * Stable antiretroviral therapy for at least 12 months * Screening CD4+ T cell count \< 350 cells/mm3 * All available CD4+ T cell counts in the last year and at screening \< 350 cells/mm3 * Screening plasma HIV RNA levels below level of detection (\< 50 copies RNA/mL using Roche Amplicor or \< 75 copies/mL using Bayer bDNA or \< 40 copies/mL using Abbott RT-PCR), and all available determinations in past 12 months also below level of detection (isolated single values \> 75 but \< 1000 copies/mL will be allowed if they were preceded and followed by undetectable viral load determinations). * \>90% adherence to therapy within the preceding 30 days, as determined by self-report * Both male and female adult (at least 18 years old) subjects are eligible. 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. Exclusion Criteria: * Patients who are intending to modify antiretroviral therapy in the next 24 weeks for any reason * Serious illness requiring hospitalization or parental antibiotics within preceding 3 months * \*\*Any vaccination 2 weeks prior to baseline (day 0) visit and throughout the study period * Concurrent treatment with immunomodulatory drugs, or exposure to any immunomodulatory drug in past 16 weeks * Concurrent treatment with phenobarbital, phenytoin, or rifampin. * Screening absolute neutrophil count \<1,000 cells/mm3, platelet count \<70,000 cells/mm3, hemoglobin \< 8 mg/dL, estimated creatinine clearance \<40 mL/minute * Pregnant or breastfeeding women