Relationship of aging and cytokines to the immunomodulation by delta-9-tetrahydrocannabinol on murine lymphoid cells

Differential effects of self-reported lifetime marijuana use on interleukin-1 alpha and tumor necrosis factor in African American adults

It is unknown how lifetime marijuana use affects different proinflammatory cytokines. The purpose of the current study is to explore potential differential effects of lifetime marijuana use on interleukin-1 alpha (IL-1α) and tumor necrosis factor (TNF) in a community based sample. Participants included 168 African American adults (51 % female, median age = 47 years). Upon study entry, blood was drawn and the participants completed questions regarding illicit drug use history whose answers were used to create three groups: lifetime non-drug users (n = 77), lifetime marijuana only users (n = 46) and lifetime marijuana and other drug users (n = 45). In the presence of demographic and physiological covariates, non-drug users were approximately two times more likely (AOR 2.73, CI 1.18, 6.31; p = .03) to have higher TNF levels than marijuana only users. Drug use was not associated with IL-1α. The influence of marijuana may be selective in nature, potentially localizing around innate immunity and the induction of cellular death.

Self-reported lifetime marijuana use and interleukin-6 levels in middle-aged African Americans

BACKGROUND

Research examining the relationship between marijuana and cytokine function has been well developed in the biochemical literature. However, scant literature exists regarding this relationship between inflammatory markers and marijuana use in public health or behavioral studies and is virtually nonexistent in non-neurologically compromised African American samples.

METHODS

The current study examined the differences in serum interleukin-6 (IL-6), a proinflammatory cytokine, between non-drug users (n=78), marijuana only users (n=46) and marijuana plus other drugs users (n=45) in a community-based sample of middle aged African Americans. Participants included 169 African American adults (50.30% female), with a mean age of 45.68 years (SD=11.72 years) from the Washington, DC metropolitan area. Serum was drawn upon entry into the study and the participants completed a demographic questionnaire, which included questions regarding drug use history.

RESULTS

After adjusting for demographic and physiological covariates, analysis of covariance revealed a significant difference between the three groups, F(2,158)=3.08, p=0.04). Post hoc analyses revealed lifetime marijuana only users had significantly lower IL-6 levels (M=2.20 pg/mL, SD=1.93) than their lifetime nonuser counterparts (M=3.73 pg/mL, SD=6.28). No other comparisons among the groups were statistically significantly different.

CONCLUSION

The current findings extend previous cellular and biochemical literature, which identifies an inverse association between IL-6 and marijuana use. Examining this relationship in the psychological and behavioral literature could be informative to the development of clinical interventions for inflammatory diseases.

Effects on the immune system

Marijuana and other exogenous cannabinoids alter immune function and decrease host resistance to microbial infections in experimental animal models and in vitro. Two modes of action by which delta9-tetrahydrocannabinol (THC) and other cannabinoids affect immune responses have been proposed. First, cannabinoids may signal through the cannabinoid receptors CB1 and CB2. Second, at sites of direct exposure to high concentrations of cannabinoids, such as the lung, membrane perturbation may be involved. In addition, endogenous cannabinoids or endocannabinoids have been identified and have been proposed as native modulators of immune functions through cannabinoid receptors. Exogenously introduced cannabinoids may disturb this homoeostatic immune balance. A mode by which cannabinoids may affect immune responses and host resistance maybe by perturbing the balance of T helper (Th)1 pro-inflammatory versus Th2 anti-inflammatory cytokines. While marijuana and various cannabinoids have been documented to alter immune functions in vitro and in experimental animals, no controlled longitudinal epidemiological studies have yet definitively correlated immunosuppressive effects with increased incidence of infections or immune disorders in humans. However, cannabinoids by virtue of their immunomodulatory properties have the potential to serve as therapeutic agents for ablation of untoward immune responses.