BACKGROUND: Chronic inflammation, as defined by persistent immune activation (IA) is associated with adverse clinical outcomes. People who inject drugs (PWIDs) have evidence of persistent IA. Here, in a cohort of HCV+ and HCV- infection drug users (IDU), we sought to dissect out the contribution of chronic hepatitis C infection (HCV, common in PWID) from the effects of drug injection itself.
METHODS: Four groups of study volunteers were recruited- Group 1- active PWID, Group 2- individuals who ceased injecting for 1-2 months, Group 3- individuals who ceased injecting for 3-4 months, and Group 4- healthy volunteers. Soluble and cell associated markers of immune activation were quantified. (https://clinicaltrials.gov/ct2/show/NCT01831284)
RESULTS: HCV viremic PWID have elevated levels of IA when compared to healthy volunteers. Cessation of IDU results in a decline in IA in the absence of HCV viremia, while HCV-viremic, former IDUs continue to harbor elevated levels of IA as defined by sCD14, TNF-alpha and the presence of CD38+HLA-DR+ CD4+ and CD8+ T cells.
CONCLUSIONS: IA, a well-defined surrogate of poor clinical outcome, elevated in PWID can regress to normal levels in former IDUs who are HCV-aviremic. Therefore, enhanced harm reduction efforts should incorporate aggressive treatment of HCV infection.
Chronic hepatitis C infection and the pro-inflammatory effects of injection drug use
Journal of Infectious Diseases, 214 (9), 1376-1382. doi: 10.1093/infdis/jiw373. PMCID: PMC5079368.