A juggernaut of innate & adaptive immune cells in chronic hepatitis C

Abstract

Hepatitis C virus (HCV) is a small positive-sense, single-stranded RNA virus, the causal organism for chronic hepatitis. Chronic hepatitis leads to inflammation of liver, causing cirrhosis, fibrosis and steatosis, which may ultimately lead to liver cancer in a few cases. Innate and adaptive immune responses play an important role in the pathogenesis of HCV infection, thus acting as an important component in deciding the fate of the disease. Numerous studies have indicated that the derangement of these immune responses results in the persistence of infection leading to chronic state of the disease. Interactions between virus and host immune system generally result in the elimination of virus, but as the virus evolves with different evading mechanisms, it makes environment favourable for its survival and replication. It has been reported that HCV impairs the immune system by functional modulation of the cells of innate as well as adaptive immune responses, resulting in chronic state of the disease, influencing the response to antiviral therapy in these patients. These defects in the immune system lead to suboptimal immune responses and therefore, impaired effector functions. This review highlights the involvement or association of different immune cells such as natural killer cells, B cells, dendritic cells and T cells in HCV infection and how the virus plays a role in manipulating certain regulatory mechanisms to make these cells dysfunctional for its own persistence and survival.

Defense Mechanism of the Immune System Against Hepatitis C Infection

“…The life cycle of HCV is directly associated with hepatic lipid metabolism and contributes for the viral persistence, in addition to interfering with the host's homeostasis of lipids, lipoproteins and cholesterol, which can cause, for example, hepatic steatosis, for example, an histological characteristic of the liver of patients infected with HCV [5].…”

“…In view of the studies read and proposed, it is understood that hepatitis C is a pathology which tends to chronicity in most cases, as the acute phase is mostly diagnosed as subclinical [5]. Thus, HCV is a highly complex pathogen.…”

“…The transmission takes place through the sharing of objects, such as syringes contaminated with the infected person's blood, in the use of injecting drugs [4]. It also occurs through failures of health professionals, when reusing materials that can promote the spread of contamination, in addition to the absence of sterilization of manicure materials in salons, corroborate the transmissibility [5]. Furthermore, despite being common and frequent compared to hepatitis B, unprotected sexual contact can be a way of contamination with HCV, however, the spread of the virus is inefficient in this form of exposure [1].…”