Objectives: There are few studies with conflicting results on the effects of in vivo administration of opioids on immune function. The aim of this study was to evaluate the serum levels of interferon (IFN)-γ, interleukin (IL)-4, IL-10, IL-17, and hs-C-reactive protein (hs-CRP) in opium smokers.
Methods: The study was conducted between 44 male opium addicts and 44 controls aged 20 to 40 years. The control group was healthy individuals with no lifetime history of substance abuse. All the opium abusers were selected from those who had a history of use of opium, as a regular habit, at least for 1 year, with a daily opium dosage of not less than 2 g. Addicts known to abuse alcohol or other drugs were excluded. Serum samples were collected from all participants and tested for the cytokine and hs-CRP levels by ELISA (enzyme-linked immunosorbent assay) method. Statistical analysis was performed using the Student t test.
Results: The mean serum levels of IFN-γ, IL-10, and IL-17 in the opium addicts were significantly higher than those observed in the control group. The mean concentration of serum IL-4 in opium addicts did not differ from that in the control group. Systemic IL-10 levels correlated positively and significantly with CRP in opium addicts.
Conclusions: Long-term, daily use of opium is associated with higher Th1 (IFN-γ), Tr1 (IL-10), and Th17 (IL-17) cytokines concentration in serum. Interferon-γ and IL-17 are involved in inducing and mediating proinflammatory responses. Our data suggest that an immunoregulatory response is occurring with the upregulation of IL-10.