The Human Liver-Expressed Lectin CD302 Restricts Hepatitis C Virus Infection.

C-type lectin domain-containing proteins (CTLDcps) shape host responses to pathogens and infectious disease outcomes. Previously, we identified the murine CTLDcp Cd302 as restriction factor, limiting hepatitis C virus (HCV) infection of murine hepatocytes. In this study, we investigated in detail the human orthologue's ability to restrict HCV infection in human liver cells. CD302 overexpression in Huh-7.5 cells potently inhibited infection of diverse HCV chimeras representing seven genotypes. Transcriptional profiling revealed abundant CD302 mRNA expression in human hepatocytes, the natural cellular target of HCV. Knockdown of endogenously expressed CD302 modestly enhanced HCV infection of Huh-7.5 cells and primary human hepatocytes. Functional analysis of naturally occurring CD302 transcript variants and engineered CD302 mutants showed that the C-type lectin-like domain (CTLD) is essential for HCV restriction, whereas the cytoplasmic domain (CPD) is dispensable. Coding single nucleotide polymorphisms occurring in human populations and mapping to different domains of CD302 did not influence the capacity of CD302 to restrict HCV. Assessment of the anti-HCV phenotype at different life cycle stages indicated that CD302 preferentially targets the viral entry step. In contrast to the murine orthologue, overexpression of human CD302 did not modulate downstream expression of nuclear receptor-controlled genes. Ectopic CD302 expression restricted infection of liver tropic hepatitis E virus (HEV), while it did not affect infection rates of two respiratory viruses, including respiratory syncytial virus (RSV) and the alpha coronavirus HVCoV-229E. Together, these findings suggest that CD302 contributes to liver cell-intrinsic defense against HCV and might mediate broader antiviral defenses against additional hepatotropic viruses. IMPORTANCE The liver represents an immunoprivileged organ characterized by enhanced resistance to immune responses. However, the importance of liver cell-endogenous, noncytolytic innate immune responses in pathogen control is not well defined. Although the role of myeloid cell-expressed CTLDcps in host responses to viruses has been characterized in detail, we have little information about their potential functions in the liver and their relevance for immune responses in this organ. Human hepatocytes endogenously express the CTLDcp CD302. Here, we provide evidence that CD302 limits HCV infection of human liver cells, likely by inhibiting a viral cell entry step. We confirm that the dominant liver-expressed transcript variant, as well as naturally occurring coding variants of CD302, maintain the capacity to restrict HCV. We further show that the CTLD of the protein is critical for the anti-HCV activity and that overexpressed CD302 limits HEV infection. Thus, CD302 likely contributes to human liver-intrinsic antiviral defenses.

Quality-of-life scores improve after 96 weeks of PEG-IFNa-2a treatment of hepatitis D: An analysis of the HIDIT-II trial.

BACKGROUND & AIMS: Infection with the hepatitis D virus (HDV) causes the most severe form of viral hepatitis with a high risk to develop clinical complications of liver disease. In addition, hepatitis delta has been shown to be associated with worse patient-reported outcomes. Until recently, only pegylated interferon alfa could be used to treat hepatitis delta. METHODS: Here, we investigated quality of life (QOL) as assessed by the Short Form 36 Health Survey (SF-36) in patients undergoing antiviral therapy with pegylated interferon alfa (PEG-IFNa-2a)-based treatment in the HIDIT-II trial. HIDIT-II was a randomized prospective trial exploring PEG-IFNa-2a with tenofovir disoproxil (TDF) or placebo for 96 weeks in patients with compensated hepatitis delta. Surveys completed by 83 study participants before, during, and after treatments were available. RESULTS: Overall, we observed a reduced QOL of HDV patients compared with a reference population, both in physical as well as mental scores. Interestingly, PEG-IFNa-2a treatment showed only minor impairment of the QOL during therapy. Moreover, HDV-RNA clearance was not associated with relevant changes in physical or social SF-36 scores, whereas an improvement of fibrosis during treatment was associated with increased QOL. Overall, slight improvements of the QOL scores were observed 24 weeks after the end of treatment as compared with baseline. TDF co-treatment had no influence on QOL. CONCLUSIONS: Overall, our findings suggest that PEG-IFNa-2a was reasonably tolerated even over a period of 96 weeks by hepatitis D patients reporting SF-36 questionnaires. Of note, several patients may benefit from PEG-IFNa-2a-based therapies with off-treatment improvements in quality of life.

Dynamic evolution of the sofosbuvir-associated variant A1343V in HEV-infected patients under concomitant sofosbuvir-ribavirin treatment.

Background & Aims: In the absence of a hepatitis E virus (HEV)-specific antiviral treatment, sofosbuvir has recently been shown to have antiviral activity against HEV in vivo. However, a variant, A1343V, that is strongly associated with viral relapse impedes treatment success. In this study, we investigated the occurrence of variants during sofosbuvir and ribavirin treatment in vivo and assessed the sensitivity of resistance-associated variants to concurrent treatment in cell culture. Methods: Two patients with chronic HEV infection that did not clear infection under ribavirin treatment were subsequently treated with a combination of sofosbuvir and ribavirin. We determined response to treatment by measuring liver enzymes and viral load in blood and stool. Moreover, we analyzed viral evolution using polymerase-targeted high-throughput sequencing and assessed replication fitness of resistance-associated variants using a HEV replicon system. Results: Combination treatment was successful in decreasing viral load towards the limit of quantification. However, during treatment sustained virological response was not achieved. Variants associated with sofosbuvir or ribavirin treatment emerged during treatment, including A1343V and G1634R. Moreover, A1343V, as a single or double mutation with G1634R, was associated with sofosbuvir resistance during concomitant treatment in vitro. Conclusions: These results highlight the importance of variant profiling during antiviral treatment of patients with chronic infection. Understanding how intra-host viral evolution impedes treatment success will help guide the design of next-generation antivirals. Impact and implications: The lack of hepatitis E virus (HEV)-specific antivirals to treat chronic infection remains a serious health burden. Although ribavirin, interferon and sofosbuvir have been reported as anti-HEV drugs, not all patients are eligible for treatment or clear infection, since resistant-associated variants can rapidly emerge. In this study, we analyzed the efficacy of sofosbuvir and ribavirin combination treatment in terms of HEV suppression, the emergence of resistance-associated variants and their ability to escape treatment inhibition in vitro. Our results provide novel insights into evolutionary dynamics of HEV during treatment and thus will help guide the design of next-generation antivirals.

Early onset renal cell carcinoma in an adolescent girl with germline FLCN exon 5 deletion.

Birt-Hogg-Dube (BHD) disease is an autosomal dominant cancer syndrome characterized by benign skin tumors, renal cancer and spontaneous pneumothorax and is caused by mutations in the Folliculin (FLCN) gene. Benign skin tumors and pneumothorax occur in the majority of patients affected by BHD syndrome, but only 30-45% of them develop renal cell carcinoma (RCC) with a median age of diagnosis at 48. The earliest onset of RCC in a BHD patient has been reported at age 20. Here we report a case of a 14 year-old patient with germline FLCN mutation leading to an early-onset bulky RCC that could not be classified strictly according to existing histological types. Germline genetic testing revealed a deletion at FLCN exon 5. The father of the patient was identified as the asymptomatic carrier. We report the youngest patient with BHD-related RCC. This early onset presentation supports genetic testing of at-risk patients and initiation of imaging surveillance for RCC in early adolescence. In addition, future studies are necessary to understand the determinants of reduced penetrance in BHD disease.