Cannabis and the immune response: A comprehensive review of therapeutic potential and concerns

Cannabis has long been esteemed for its analgesic, anti-inflammatory, and sedative characteristics. Ancient people such as the Egyptians, Greeks, and Chinese acknowledged the curative value of their medicinal practices. The identification of the endocannabinoid system, which engages with cannabis phytochemicals, has elucidated the mechanisms by which cannabis influences the human immune system, including the central nervous system. Cannabis and its bioactive components, particularly cannabinoids such as delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), have garnered substantial interest for their potential therapeutic effects. This review comprehensively examines the interactions between cannabis and the immune system, focusing on immune cell function, clinical evidence, molecular mechanisms, and ongoing controversies. Cannabinoids modulate immune responses by interacting with cannabinoid receptors (CB1 and CB2) expressed on various immune cells. THC generally exhibits immunosuppressive properties beneficial in conditions such as autoimmune diseases, whereas CBD shows anti-inflammatory effects without broadly suppressing immune function. The review also highlights the complex impact of cannabinoids on T lymphocytes, B lymphocytes, macrophages, dendritic cells, and natural killer cells, influencing cytokine production and immune signaling pathways. Clinical studies suggest that cannabinoids may alleviate symptoms of multiple sclerosis, rheumatoid arthritis, and systemic lupus erythematosus, although their long-term impact on immune competence remains uncertain. Epidemiological studies indicate that chronic cannabis use may alter immune responses, with both beneficial and adverse effects. The review underscores the need for more extensive research to understand the dose-dependent immunomodulatory effects of cannabinoids and their potential for developing personalized therapeutic strategies. Emerging trends in cannabinoid research and the potential for cannabis-based therapies in immune-related diseases are also discussed, highlighting the promise and challenges in this evolving field.