Drug abuse, innate immunity and hepatitis C virus
William Penn University, Filadelfia, Pennsylvania, United States Reviews in Medical Virology
(Impact Factor: 5.57).
09/2006; 16(5):311-27. DOI: 10.1002/rmv.508
Since its discovery in 1989, hepatitis C virus (HCV) has become a major public health problem. HCV chronically infects an estimated 170 million people worldwide. The seroprevalence of anti-HCV antibody in the United States has been estimated at 1.8%, which corresponds to approximately 4 million people. HCV is the most common chronic blood borne infection in the United States, and the leading cause of liver transplantation in developed countries. Injection drug use is the dominant mode of HCV transmission and accounts for up to 90% of current infections. Opiates and other drug abuse, such as alcohol, have been implicated as cofactors in the pathogenesis of HCV disease. Injection drug use has been the most common risk factor identified in alcoholics with HCV infection. Both opiates and alcohol contribute significantly to morbidity and mortality from HCV disease. These drugs most likely act synergistically to promote the development and progression of HCV disease. However, there is limited information available concerning the interaction of the drug abuse with the host cell innate immunity against HCV infection, which is a major barrier to fundamental understanding of the immunopathogenesis of HCV disease. Therefore, defining the role of the drug abuse in the development of chronic HCV infection is of crucial importance and should provide practical guidance toward the reduction of risk factors that interfere with therapeutic approaches for HCV infection and disease. This review paper focuses on the interplay between drug abuse (opiates and alcohol), innate immunity and HCV in the context of the development of HCV disease.
Available from: Jieliang Li
- "Although the role of opiates in promoting HIV disease progression is still debatable, overwhelming evidence indicates that heroin and other opiate derived substances affect both adaptive and innate immunity , , , . Innate immunity is the first line of the defense mechanism against viral infections. "
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ABSTRACT: Opioids exert a profound influence on immunomodulation and enhance HIV infection and replication. However, the mechanism(s) of their action remains to be determined. We thus investigated the impact of morphine on the intracellular innate antiviral immunity.
Seven-day-cultured macrophages were infected with equal amounts of cell-free HIV Bal or SIV Delta(B670) for 2 h at 37°C after 24 h of treatment with or without morphine. Effect of morphine on HIV/SIV infection and replication was evaluated by HIV/SIV RT activity assay and indirect immunofluorescence for HIV p24 or SIV p28 antigen. The mRNA expression of cellular factors suppressed or induced by morphine treatment was analyzed by the real-time RT-PCR. We demonstrated that morphine treatment of human blood monocyte-derived macrophages significantly inhibited the expression of interferons (IFN-α, IFN-β and IFN-λ) and IFN-inducible genes (APOBEC3C/3F/3G and 3H). The further experiments showed that morphine suppressed the expression of several key elements (RIG-I and IRF-7) in IFN signaling pathway. In addition, morphine treatment induced the expression of suppressor of cytokine signaling protein-1, 2, 3 (SOCS-1, 2, 3) and protein inhibitors of activated STAT-1, 3, X, Y (PIAS-1, 3, X, Y), the key negative regulators of IFN signaling pathway.
These findings indicate that morphine impairs intracellular innate antiviral mechanism(s) in macrophages, contributing to cell susceptibility to AIDS virus infection.
Available from: Santanu Banerjee
- "In vitro studies implicated intravenous opioid abuse with promotion of HIV infection via decreased secretion of α and β chemokines and stimulation of chemokine receptors CCR5 and CCR3 (coreceptors for HIV) (Nath et al., 2002; Vallejo et al., 2004). At the same time, studies on hepatocytes indicated increased hepatitis C virus replication and decreased susceptibility to IFN-α therapy in the setting of chronic morphine treatment (Li et al., 2003; Zhang et al., 2006). Epidemiologic studies provide data on increased prevalence of opportunistic bacterial infections such as TB and pneumonia in IDUs, with a 10-fold increase in the incidence of pneumonia among this population (Hind, 1990; Perlman et al., 1995). "
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ABSTRACT: Infection rate among intravenous drug users (IDU) is higher than the general public, and is the major cause of morbidity and hospitalization in the IDU population. Epidemiologic studies provide data on increased prevalence of opportunistic bacterial infections such as TB and pneumonia, and viral infections such as HIV-1 and hepatitis in the IDU population. An important component in the intravenous drug abuse population and in patients receiving medically indicated chronic opioid treatment is opioid withdrawal. Data on bacterial virulence in the context of opioid withdrawal suggest that mice undergoing withdrawal had shortened survival and increased bacterial load in response to Salmonella infection. As the body of evidence in support of opioid dependency and its immunosuppressive effects is growing, it is imperative to understand the mechanisms by which opioids exert these effects and identify the populations at risk that would benefit the most from the interventions to counteract opioid immunosuppressive effects. Thus, it is important to refine the existing animal model to closely match human conditions and to cross-validate these findings through carefully controlled human studies. Better understanding of the mechanisms will facilitate the search for new therapeutic modalities to counteract adverse effects including increased infection rates. This review will summarize the effects of morphine on innate and adaptive immunity, identify the role of the mu opioid receptor in these functions and the signal transduction activated in the process. The role of opioid withdrawal in immunosuppression and the clinical relevance of these findings will also be discussed.
Available from: Chris Carter
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ABSTRACT: Peptide stretches within HIV-1 proteins display homology to over 50 components from all compartments of the human immune defence network. The homologous peptides are in most cases immunogenic, suggesting that antibodies to HIV-1 proteins could mount an autoimmune attack against multiple components of the immune system itself. HIV-1 proteins are also homologous to autoantigens in Alzheimer's disease, chronic obstructive pulmonary disorder, multiple sclerosis, Myasthenia Gravis, Pemphigus Vulgaris, Sjogrens syndrome and systemic Lupus Erythematosus, all of which have been associated with HIV-1 infection. This mimicry suggests that HIV-1/AIDS has a major autoimmune component and that HIV-1 antibodies could selectively target the immune system and autoantigens in other autoimmune disorders. This could radically change our conception of how HIV-1 acts, and perhaps lead to novel therapeutic strategies, which, counter intuitively might even involve the use of immunosuppressants in the early stages of the disease. Autoantigens from the human autoimmune diseases mentioned above also align with peptides from other viruses implicated as risk factors in each disease. Mutant peptides from Huntington's disease and other polyglutamine disorders, and from cystic fibrosis also align with common viruses. The London APP717 V→I mutant in Familial Alzheimer's disease converts the surrounding peptide to matches with Rhinoviruses causing the common cold and to the Norovirus responsible for vomiting sickness. Viral mimicry related autoimmunity may thus play a role in many autoimmune and even human genetic disorders. It is possible that this is a near universal phenomenon, reflecting the idea that viruses are responsible for the origin of higher forms of life, leaving behind a deadly legacy of viral-derived human proteins with homology to antigenic proteins in the current virome that may be responsible for most of our ills.
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