The impact of IL28B genetic variants on recurrent hepatitis C in liver transplantation: significant lessons from a dual graft case

Histopathological evaluation of recurrent hepatitis C after liver transplantation: A review

Although the morphological features of hepatitis C virus (HCV) recurrence after orthotopic liver transplantation (OLT) have been well established in the last decades, the differential diagnosis still represents a challenge for the pathologist, especially early recurrent hepatitis C vs mild acute cellular rejection. The present review focuses on the role of the pathologist and the pathology laboratory in the management of recipients with recurrent hepatitis C, the usefulness of early and late post-OLT liver biopsies, and the potential role of ancillary techniques (immunohistochemistry and reverse transcription-polymerase chain reaction, RT-PCR). The English literature on the topic is reviewed, focusing on the histopathology, the immunohistochemistry and the use of RT-PCR on HCV-positive post-OLT biopsies. The different histopathological illustrations of early and chronic recurrent hepatitis C are presented, with special focus on the main differential diagnoses and those features with prognostic relevance (cholestasis above all). The usefulness of ancillary techniques are discussed, especially HCV RNA quantitation by RT-PCR. Finally, the usefulness of long-term protocol biopsies is addressed: their usefulness for the study of allograft disease progression is clear, but their meaning in the long term is still debated. The significance of plasma cell infiltrate in HCV-positive allografts, the prognostic weight of graft steatosis, and the impact of donor age in recurrent hepatitis C also represent additional open issues.

Hepatitis C virus viral assays in the direct-acting antiviral era

In the direct-acting antiviral (DAA) era of hepatitis C virus (HCV) therapy, health care providers must be knowledgeable about genotype and subtype of HCV infection and interpretation of quantitative HCV viral assays to monitor treatment responses. They may also choose to assess interleukin 28B genotypes or resistance-associated variants after ineffective DAA therapy. DAA therapies require understanding of performance characteristics of quantitative HCV RNA assays and the definitions of terms used to report results. Only quantitative HCV RNA assays with a limit of detection of 10 to 15 IU/mL are appropriate for managing patients on DAA therapy.

Interleukin-28B polymorphism in hepatitis C and liver transplantation

The discovery of interleukin-28B (IL-28B) single-nucleotide polymorphisms has opened an important new area of research in liver transplantation (LT) for hepatitis C virus (HCV). Both recipient- and donor-derived IL-28B genotypes affect the post-LT treatment response, with sustained virological response (SVR) rates oscillating from >50% in homozygotes for the favorable allele (up to 90% when this is present in both the recipient and the donor) to <15% in homozygotes for the unfavorable allele and from 30% to 50% in heterozygotes. Other key posttransplant outcomes affected by the IL-28B genotype are the time to histological recurrence, HCV RNA and alanine aminotransferase levels, histological variables (including the rate of fibrosis progression), and hepatocellular carcinoma. Interactions between donor and recipient IL-28B genotypes are complex and may affect outcomes not directly related to HCV infections, such as acute cellular rejection (ACR) and metabolic diseases. A preferential allocation system in which livers from donors homozygous for the favorable allele are given to HCV patients might be postulated to improve SVR rates and post-LT outcomes in recipients with HCV infections (a 25% increase in SVR and an 8% decrease in mortality at 5 years). Although negative effects from this are difficult to predict, they could include an accelerated progression of fibrosis in patients with failed HCV eradication and an increase in ACR in non-HCV patients. Our knowledge of the precise role of IL-28B genotypes in the course of post-LT HCV is evolving, but existing knowledge suggests the possibility of exploring strategies that use IL-28B genotyping to reduce the impact of post-LT adverse outcomes.

Hepatic transplant and HCV: a new playground for an old virus

Hepatitis C virus (HCV) infection is a major global health problem affecting 170 million people worldwide. The majority of infected individuals fail to resolve their infection, with a significant number developing chronic, progressive HCV-related liver disease. HCV infection is the leading indication for liver transplantation and unfortunately, all patients with detectable viral load before transplantation will have rapid, recurrent infection. What remain to be determined are factors contributing to the severity of HCV recurrence. Such factors are unique to the posttransplant setting and include: viral genetic diversity and composition, immunosuppression, donor/recipient age and sex, genetic factors and the liver microenvironment. Importantly, the possibility that the severity of HCV recurrence might be also influenced by factors related to the primary course of disease (i.e. viral set point, previously acquired adaptations of the virus) must be further evaluated. In this sense, recurrent HCV infection should not be regarded merely as another acute infection, but rather, it should be cautioned that problems first arising during the primary course of disease may be accentuated during recurrence. Development of novel therapeutic approaches will require a thorough understanding of viral and host determinants of infection resolution and how these factors may change in the posttransplant setting.