The occurrence of autoantibodies in patients with chronic HCV infection, including patients dialyzed and after kidney transplantation

High prevalence of antinuclear antibodies in patients with chronic hepatitis C virus infection

Background

Hepatitis C virus (HCV) infection is a serious public health concern due to its high prevalence and mortality rate. In chronic infection, HCV may induce autoimmune responses through the production of autoantibodies, including antinuclear antibodies (ANA).

Methods

We assessed the presence of ANA by indirect immunofluorescence using HEp-2 cells in 89 patients with chronic hepatitis C. We also collected data on epidemiological variables; clinical characteristics; and biochemical, hematological, molecular, and histopathological information from the patients to assess the impact of the presence of ANA in those patients.

Results

The prevalence of ANA in the patients was 20.2%, which was significantly higher than that found in healthy controls (2%). However, there was no association of this marker with epidemiological, clinical-laboratory, molecular or histopathological characteristics of hepatitis C, although a slightly higher prevalence of ANA was detected in women and in patients infected with subgenotype 1a. In a specific analysis, chronic HCV patients with the “rods and rings” cytoplasmic pattern had higher degrees of hepatic fibrosis than did ANA-negative patients.

Conclusions

The results confirm a greater predisposition to the presence of ANA in patients with HCV, which may be associated with a worse prognosis, especially in the presence of the “rods and rings” cytoplasmic pattern.

Exploratory Study of Autoantibody Profiling in Drug-Induced Liver Injury with an Autoimmune Phenotype

Drug-induced liver injury (DILI) sometimes presents with an autoimmune hepatitis-like phenotype (AI-DILI), and it is challenging to distinguish it from de novo autoimmune hepatitis (AIH). We conducted a study to identify autoantibodies unique to AI-DILI by profiling serum autoantibodies. Autoantibodies were quantified using an autoantigen array containing 94 autoantigens from four groups: AI-DILI (n = 65), DILI controls (n = 67), de novo AIH (n = 17), and healthy controls (HCs; n = 30). In 37 patients with AI-DILI, samples were also collected 6 months after presentation. AI-DILI and de novo AIH had similar anti-neutrophil antibody and anti-smooth muscle antibody prevalence. Compared to HCs, de novo AIH had an increase in many immunoglobulin G (IgG; 35 [46.1%]) and IgM (51 [70%]) autoantibodies, whereas AI-DILI had an increase of IgM (40 [54.8%]) but not IgG autoantibodies. DILI controls had a similar IgG and IgM profile compared to HCs. Comparing de novo AIH to AI-DILI identified 18 (23.7%) elevated IgG but only one (1.4%) IgM autoantibodies, indicating the unique IgG autoantibody profile in de novo AIH. Compared to DILI and HCs, increased IgM autoantibodies in AI-DILI and de novo AIH were common; however, AI-DILI induced by different drugs showed different frequencies of IgM autoantibodies, with nitrofurantoin-related AI-DILI showing a higher number of increased IgM autoantibodies. AI-DILI autoantibody levels at diagnosis and at 6 months showed a significant decline in 37 IgM autoantibodies. A model with highly correlated IgG and IgM was fitted into multivariate logistic regression and revealed an area under the curve of 0.87 (95% confidence interval, 0.79-0.95) to distinguish de novo AIH from AI-DILI. Conclusion: The unique IgG and IgM autoantibody signature appears to be a promising biomarker for distinguishing AI-DILI from de novo AIH.

Potential pathogenic mechanisms involved in the association between lichen planus and hepatitis C virus infection

Lichen planus (LP) is an immune-mediated inflammatory disease that particularly affects the skin and mucous membranes. Its etiology remains elusive, however some trigger factors, including viral or bacterial antigens, drugs and metals, have been postulated. There is a higher prevalence of hepatitis C virus (HCV) infection among patients with LP, with some geographical variations. HCV is an enveloped RNA virus that belongs to the Flaviviridae family and in most instances causes chronic liver infections. It has been hypothesized that HCV may contribute to LP development, but the link between the two disorders is not fully understood. It is still debatable whether HCV leads to the occurrence of LP lesions directly by replication inside the infected cells or indirectly by activating immunological pathways. Molecular studies have revealed HCV RNA in specimens collected from patients with LP. The autoimmune theory was also suggested given that several studies have revealed viral replication and immune response activation associated with autoantibody synthesis. The aim of this review is to summarize the main potential mechanisms involved in the association between LP and HCV infection. Understanding the link between the two disorders may shed some light on the pathogenesis of LP, which is a challenging issue.

Modulation of the Immune System in Chronic Hepatitis C and During Antiviral Interferon-Free Therapy

The treatment of patients with chronic hepatitis C virus (HCV) infection has changed tremendously over the past 2 years, with an increasing variety of all-oral direct-acting antiviral (DAA) treatment regimens available for different HCV genotypes and distinct clinical settings. These treatments have significantly improved safety in patients with advanced liver disease compared with interferon (IFN)-based regimens. HCV modifies the human immune system to escape immunosurveillance via several mechanisms. One of the basic mechanisms of HCV is the ability to “switch” the immune response by reducing the activity of cells responsible for the elimination of virus-infected cells. IFN-free DAA treatment regimens provide a unique opportunity to assess the effect of HCV elimination on the immune system. Abrupt changes in the immune system can in some cases be responsible for two alarming processes: viral reactivation in patients with chronic hepatitis B and recurrence of hepatocellular carcinoma in patients with previous successful cancer treatment.