Heroin Use Is Associated with Suppressed Pro-Inflammatory Cytokine Response after LPS Exposure in HIV-Infected Individuals

BACKGROUND Opioid use is associated with increased incidence of infectious diseases. Although experimental studies have shown that opioids affect various functions of immune cells, only limited data are available from human studies. Drug use is an important risk factor for HIV transmission; however no data are available whether heroin and/or methadone modulate immune response. Therefore, we examined the effect of heroin and methadone use among HIV-infected individuals on the production of cytokines after ex vivo stimulation with various pathogens. METHODS Treatment naïve HIV-infected individuals from Indonesia were recruited. Several cohorts of individuals were recruited: 1) using heroin 2) receiving methadone opioid substitution 3) using heroin over 1 year ago and 4) controls (never used opioids). Whole blood was stimulated with Mycobacterium tuberculosis, Candida albicans and LPS for 24 to 48 hours. Cytokine production (IL-1 β, IL-6, IL-10, IFN-α, IFN-γ and TNF-α) was determined using multiplex beads assay. RESULTS Among 82 individuals, the cytokine levels in unstimulated samples did not differ between groups. Overall, heroin users had significantly lower cytokine response after exposure to LPS (p<0.05). After stimulation with either M. tuberculosis or C. albicans the cytokine production of all groups were comparable. CONCLUSION The cytokine production after exposure to LPS is significantly down-regulated in HIV-infected heroin users. Interesting, methadone use did not suppress cytokine response, which could have implications guidelines of opioid substitution.