Cannabis has been shown in studies to improve appetite, relieve chronic pain, and reduce nausea due to chemotherapy. Many people with HIV/AIDS use medical marijuana to combat wasting and other symptoms, which raises questions about what effects it might have on HIV and its progression.
Many immune cells express cannabinoid receptors, indicating that cannabis may influence immune function. Some prior research suggested that marijuana use is associated with HIV disease progression, but such studies were prone to confounding by socioeconomic and other factors related to illegal drug use.
As described in the June 2011, issue of AIDS Research and Human Retroviruses, Patricia Molina and colleagues from Louisiana State University Health Sciences Center examined the impact of ongoing administration of delta-9-tetrahydrocannabinol (THC) in macaque monkeys exposed to simian immunodeficiency virus (SIV).
Eight rhesus macaques received twice-daily intramuscular injections of either THC or a placebo. After 28 days, they were intravenously inoculated with a highly infectious dose of SIV. The researchers looked and immune and metabolic indicators of disease progression during the initial 6-month asymptomatic phase after infection.