This study will evaluate the effect of chloroquine in individuals infected with HIV. Researchers will aim to determine if chloroquine treatment in participants whose viral loads are suppressed on combination antiretroviral therapy (ART), results in improved immune activation and CD4 cell recovery.

The study will recruit 20 individuals and will last approximately 44 weeks. Eligible participants will receive an oral dose of chloroquine (250 mg) once daily from week 8 through week 32. All participants will be asked to have rectal biopsy samples (week 0 and week 32) to study T cell immune activation in the mucosa rectal site.

Clinical data has identified chloroquine as a potential modulator of immune activation. The study's dose of chloroquine is the same as the dose recommended for patients having autoimmune diseases. In these autoimmune cases, a daily dose of chloroquine at 250 mg for 12 weeks has shown improvement in symptoms and decreases in inflammatory cytokines synthesis and a reduction in TLR -mediated immune activation. Study findings could help provide information about where and under what circumstances chloroquine treatment may reduce T cell activation and help restore circulating CD4 T cells.

Inclusion Criteria:

• Documented HIV infection by Western Blot, EIA assays or viral load assay.
• Aged between 18 and 65 years.
• Viral load less than 50 copies per ml for at least the previous 36 weeks.
• CD4 cell count less than or equal to 350 cells per litre.
• On stable ART
• Vital signs, physical examination and laboratory results do not exhibit evidence diseases such as advanced cirrhosis or advanced liver
• Karnofsky performance status greater than or equal to 80 per cent.
• Participant does not require and agrees not to take, for the duration of the study, any medication that is contraindicated with chloroquine.
• Able to give informed consent.

Exclusion Criteria:

• Active AIDS events in the last 3 months
• Co-infection with active hepatitis B or C virus.
• Current use or use within four weeks prior to the baseline visit, of cytotoxic agents, systemic corticosteroids or any immuno-modulatory agents.
• Current use within four weeks prior to the chloroquine therapy the following medications: methadone, chlorpromazine, cimetidine, cyclosporin, methotrexate and penicillanime.
• Psychiatric or cognitive disturbance or illness that could preclude compliance with the study.
• Patient with clinically significant hemophilia and Von-Willebrand disease and any severe bleeding disorder.
• Experimental HIV immune based therapy within 6 months of screening visit.
• Allergic reaction to chloroquine.
• A history of retinitis or any retinal problem.
• Subjects with G6PD deficiency, porphyria, psoriasis, cirrhosis, hearing deficiency (including tinnitus), myopathy and cardiomyopathy.
• Pregnant and breast-feeding women.