Coinfection with Hepatitis C Virus and Human Immunodeficiency Virus: Virological, Immunological, and Clinical Outcomes

Abstract

Infection with hepatitis C virus (HCV) is estimated to affect 2% of the world population (90) and is a leading cause of liver-related morbidity and mortality. Human immunodeficiency virus (HIV) is also a very important global public health problem, infecting about 33 million people worldwide (129). As the transmission routes are shared by both infections, coinfection is not uncommon. In this review, we discuss the magnitude of the problem, the effect of infection with one virus on the transmission and natural history of the other, and the treatment issues unique to coinfected patients. EPIDEMIOLOGYThe reported prevalence of HIV/HCV coinfection varies significantly among studies. Although HIV and HCV are both transmitted through parenteral, sexual, and vertical exposure, they differ in the transmission efficiencies of these routes. Thus, the risk factors of the population under study directly influence the prevalence in that particular population. Parenteral exposure modes such as intravenous drug use (IVDU) or multiple transfusions have been consistently found to be the most important risk factors for coinfection (121). In HIV-positive patients with a history of IVDU, the rate of HCV infection is reported to be 82 to 93% (61,76,113). On the other hand, sexual transmission of HCV is relatively inefficient, and the rate of coinfection among HIV-infected patients with a sexual risk factor is less than 10% (61). Men who have sex with men do not seem to have an overall-increased risk for coinfection (21,61,121), although epidemics of acute HCV have been described for HIV-infected men who have sex with men with high-risk behaviors (33). The overall burden of coinfection is estimated at 4 to 5 million people worldwide (2).Apart from the shared routes of transmission, infection with HIV, when present in either HCV-transmitting or HCV-exposed patients, can have a direct effect on the risk of transmission of HCV. HIV-infected patients exposed to HCV are less likely to clear the acute infection (odds ratio, 0.46) (123). This scenario seems to be especially relevant to transmission via IVDU (110). On the other hand, coinfected individuals are more likely to transmit HCV. The rate of vertical transmission of HCV is increased about threefold for coinfected mothers (95) compared to that for HCV-monoinfected ones; this effect may be limited to women with low HCV RNA levels (Ͻ10 6 IU/ml) (69). Percutaneous exposure of health care workers to blood from coinfected patients was also shown to increase the risk of acquiring HCV (35). Although coinfected individuals have been shown to have a higher prevalence of HCV RNA in cervicovaginal secretions (85) and semen (25), sexual transmission of HCV is still rare, even to partners of coinfected patients (68). EFFECT OF HIV/HCV COINFECTION ON THE NATURAL HISTORY OF HCVCoinfection with HIV has a significant impact on the life cycle of HCV and on the natural history of HCV infection. A retrospective study of stored sera from multitransfused hemophiliac patients (42) and a similar study of IV...

Human Immunodeficiency Virus Infects Human Seminal Vesicles in Vitro and in Vivo

“…47 Whereas HIV increases HCV and HBV replication and has a negative effect on the progression of both HCV and HBV infection, 48 -51 the reverse remains unclear. 48,50,52 For example, although HIV replication in co-infected patients may, in theory, be stimulated by the persistent state of immune activation induced by chronic HBV replication and by the HBV protein HBx, 53 no significant effect of HBV carriage on HIV progression has been observed. 50 After initiation of HAART, virologic and immunologic responses are generally similar in both HCV/HIV 54,55 and HBV/HIV 56 -58 co-infected patients compared with those with HIV alone.…”

HIV Co-Infection with Hepatotropic Viruses and Mycobacterial Tuberculosis

“…The mechanisms underlying accelerated liver disease in hepatotropic viruses/HIV co-infected individuals are poorly understood but may include the following: direct viral effects on hepatocytes and hepatic stellate cells, and immunologic alterations such as immune activation, apoptosis and diminished HCV specific Tcell reponses [60][61][62][63]. In addition, liver toxicity of antiretroviral drugs and the burden of metabolic disease may contribute to a faster progression of liver fibrosis in HIV/ HCV co-infection.…”

Molecular Evolution of Hepatitis Viruses

“…This effect seems to be both related to the acquired immunodeficiency and to a direct interaction between the viruses (Rotman & Liang, 2009). In addition, HIV-1 co-infection seems to impact the quasispecies complexity exhibited by HCV.…”