Effect of Cannabis on Immune System and Viral Infections

Today, cannabis falls in the most frequently used drug globally. Almost 2 to 3 million new users add to the total number of cannabis users annually. Not only adults but children of 8^th to 12^th grades are also prey to its use.

Apart from cannabis, the world population is immensely affected by viral infections, including human immune deficiency virus, hepatitis C virus, human T lymphotropic virus type 1, and the deadly coronavirus.

Adverse effects of cannabis:

Cannabis use is associated with adverse economic, social, psychosocial, and health conditions. The psychosocial consequences such as lack of interest in education and antisocial behaviors are also the products of marijuana use¹.

The health consequences of cannabis involve the immune, cardiopulmonary/respiratory, hepatic, renal, endocrine, reproductive, and central nervous systems, including genetics and general health. We now discuss the impact cannabis has on the immune system and the risks of acquiring viral infections.

Cannabis and Immune System

By reviewing the online databases, the cannabis Sativa plant contains chemicals known as cannabinoids. The endogenous cannabinoids, the endocannabinoid system (ECS), act as immune-modulating agents and affect T-cells, B-cells, monocytes, and microglia, reducing proinflammatory cytokine expression and increasing anti-inflammatory cytokines².

Cannabidiol may serve as an immunosuppressor by suppressing the activation of immune cell types, inducing apoptosis, and promoting regulatory cells. However, there is no evidence suggesting that cannabis use impairs immune function, as measured by the number of T cell lymphocytes, B cell lymphocytes, macrophages, or immunoglobulin levels in humans³.

However, it is shown that regular heavy smoking of cannabis weakens the immune system, leading to increased symptoms of chronic bronchitis, coughing, production of sputum, wheezing, and impairment of pulmonary functions compared to nonsmokers tobacco-only smokers. Cannabis smokers also show higher levels of cytoplasmic components in their sputum when compared with sputum from tobacco smokers. Thus, marijuana smoking predisposes the individual to pulmonary infection, especially among patients whose immune defenses are compromised by HIV infection or cancer-related chemotherapy⁴.

Another side effect is that suppression of cell-mediated immunity places marijuana smokers at risk for infection or cancer. Plus, the incidence of bacterial pneumonia in HIV-seropositive subjects is highly related to smoking illicit drugs.

In the case of cannabis use during pregnancy, it negatively impacts the fetal immune system since cannabinoids cross the placental barrier. It dysregulates the fetus’s innate and adaptive immune system, leading to weakened immune defenses against infections and cancer⁵.

Medicinal Use:

Attempts have been made to investigate the medicinal properties of cannabis for pancreatitis, Inflammatory bowel disease, rheumatoid arthritis, osteoarthritis, fibromyalgia, and juvenile idiopathic arthritis since the activated ECS decreases the gut motility, secretions, and epithelial permeability and induces immune modulation by decreasing the production of cytokines. However, evidence is insufficient to support the treatment⁶.

Cannabis and Infections

Undoubtedly, cannabis increases the risk of acquiring bacterial, viral, parasitic, and fungal infections by modulating the immune system, decreasing immunity, and thus also increasing susceptibility to infections including HIV and HIV-associated opportunistic infections⁷.

Some data also suggest that cannabis use is associated with a beneficial reduction in systemic inflammation and immune activation in the context of antiretroviral-treated HIV infection. Cannabis use is not associated with progression to AIDS. It also does not affect adherence to HIV therapy. In addition, cannabis has also been used to treat common complications, including poor appetite and neuropathy in patients with HIV.

ECS regulates the homeostasis of the gut microbiome. Cannabis, having antioxidant and anti-inflammatory properties, may be used as an adjunct therapy in healing and restoring the gut microbiome in HIV-infected subjects.

Regarding chronic hepatitis C virus (HCV) infection, there are several risk factors with cannabis use that have been identified for the progression of liver fibrosis⁸.

However, neither the frequency nor the amount of cannabis use affected liver fibrosis in HIV/HCV co-infected women. Hepatic steatosis is also common in HIV/HCV-co-infected patients. Daily cannabis use is also associated with a reduced prevalence of steatosis.

Cannabis smoking is associated with cerebrovascular and neurological systems. Considering that smokers are more prone to viral and bacterial infection than nonsmokers, cannabis smoking might exacerbate the cerebrovascular and neurological dysfunction observed in patients with SARS-Cov2 infection, which results in a disease known as COVID-19⁹.

Cannabis also affects sexually transmitted infections. There are fewer STIs and a reduced risk of sexual engagement among HIV-infected homosexual men who smoked cannabis compared to nonsmokers¹⁰.

Conclusions

Research suggests a link between cannabis, immune function, and viral infections. Cannabis use may be associated with an increased risk of acquiring or transmitting infections such as HIV and HCV. However, there is insufficient data to show that cannabis use causes the progression of viral diseases.

Cannabis use is also associated with respiratory effects such as chronic cough and emphysema and the impairment of immune function. However, cannabis has some beneficial effects, such as improving appetite and food intake in patients with HIV/AIDS and positive effects in patients with hepatic steatosis. More research is needed to study the long-term effects of cannabis use.

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References:

1. National Academies of Sciences, Engineering, and Medicine; Health and Medicine Division; Board on Population Health and Public Health Practice; Committee on the Health Effects of Marijuana: An Evidence Review and Research Agenda. The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research. Washington (DC): National Academies Press (US); 2017 Jan 12. 11, Psychosocial. Available from: https://www.ncbi.nlm.nih.gov/books/NBK425739/
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