A 2013 study published in Rheumatology discovered that those with arthritis had more CB2 cannabinoid receptors on their cells than those suffering from other forms of arthritis. In this case, the CB2 receptor is involved in inflammation control. Both CBD and THC engage with CB2 receptors. THC directly connects with the receptor, triggering an anti-inflammatory response. CBD increases the amount of endocannabinoids (our human version of THC) in the body, engaging CB2 receptors in a different way. By directly engaging with the endocannabinoid system, cannabis may tap into the body’s own system of self-repair.
In 2014, researchers from the University of South Carolina found that the psychoactive cannabinoid, THC, dampens the immune system and deactivates inflammatory proteins. This quality makes THC a candidate for the treatment of a variety of autoimmune disorders, including multiple sclerosis, colitis, lupus, and arthritis.
(Source: Huan Gui et al. “Expression of cannabinoid receptor 2 and its inhibitory effects on synovial fibroblasts in rheumatoid arthritis.” Rheumatology, Volume 53, Issue 5, 1 May 2014, Pages 802–809)