Hepatitis C virus/human immunodeficiency virus coinfection in hemophiliacs: high rates of sustained virologic response to pegylated interferon and ribavirin therapy

High rate of sustained virological response with direct-acting antivirals in haemophiliacs with HCV infection: A multicenter study

BACKGROUND AND AIMS

Chronic hepatitis C is the main co-morbidity in adult patients with haemophilia (PwH). It causes progressive liver damage leading to end-stage liver disease and/or hepatocellular carcinoma. Eradication of HCV was possible with interferon (IFN)-based regimens in the past and direct-acting antivirals (DAAs) more recently. PwH have been considered "difficult-to-treat" because of several bad predictors of response. The advent of DAAs has provided high rates of sustained virological response (SVR) despite bad prognostic factors. Here, we present the results of antiviral treatment with DAAs in PwH treated in 2 large Italian Hemophilia Treatment Centers.

METHODS

PwH and chronic hepatitis C sustained by any HCV genotype were eligible for therapy with DAAs, including those with compensated cirrhosis, HIV infection and/or previous failure to IFN-based antiviral therapy. Patients received DAAs for 8-24 weeks according to existing guidelines. SVR was defined as persistent negative serum HCV-RNA at 12 weeks after treatment completion (SVR12).

RESULTS

Between January 2015 and November 2018, 200 patients aged 21-84 years (median: 50.5) received DAAs. HCV genotype 1 was the most prevalent (158, 79%). Forty patients (20%) were HIV positive, 56 (28%) had cirrhosis and 91 (46%) previously failed interferon-based treatment. Ribavirin was used in 70 (35%). HCV-RNA was undetectable at week 4 in 124/192 (65%) and SVR12 was achieved in 193/195 (99%). No patient had serious side effects related to DAAs.

CONCLUSIONS

DAAs were safe and highly effective in PwH irrespective of HIV status, stage of liver disease severity and/or previous failure to IFN-based therapy.

Interferon lambda 3 rs12979860 polymorphism in patients with haemophilia and HCV infection: a predictor of spontaneous viral clearance and sustained virological response

Chronic hepatitis C is the main cause of morbidity and mortality in adult haemophilic patients who received non-virally inactivated plasma-derived clotting factor concentrates. Overall, spontaneous viral clearance rate is 10-25% and the only approach that can halt disease progression is hepatitis C virus (HCV) eradication by means of antiviral therapy. In non-haemophilic patients a single nucleotide polymorphism located upstream the gene of interferon lambda 3 (IFNλ3) has been associated with both spontaneous viral clearance and sustained virological response after antiviral treatment. The aim of this study was to assess whether the rs12979860 polymorphism was a predictor of spontaneous viral clearance and of sustained virological response after antiviral therapy in a large cohort of haemophilic patients with HCV infection. The rs12979860 polymorphism, defined as CC genotype or T allele, was tested in a cohort of 342 haemophilic patients and evaluated as predictor of spontaneous clearance or response to antiviral therapy. By multivariate regression analysis the IFNλ3 CC genotype was an independent predictor of spontaneous viral clearance (odds ratio: 3.7, 95% confidence interval: 2.0-6.8). Sustained virological response rates were doubled in patients with the CC genotype than in those with the T allele (78% vs 44%; p<0.001), especially in patients with HCV type 1 (67% vs 32%; p<0.001) and higher sustained response rates were observed in patients with the CC genotype who did not achieve rapid virological response (61% vs 30% in T allele patients; p=0.006).

Zebrafish as a potential model organism for drug test against hepatitis C virus

Screening and evaluating anti- hepatitis C virus (HCV) drugs in vivo is difficult worldwide, mainly because of the lack of suitable small animal models. We investigate whether zebrafish could be a model organism for HCV replication. To achieve NS5B-dependent replication an HCV sub-replicon was designed and created with two vectors, one with HCV ns5b and fluorescent rfp genes, and the other containing HCV's 5′UTR, core, 3′UTR and fluorescent gfp genes. The vectors containing sub-replicons were co-injected into zebrafish zygotes. The sub-replicon amplified in liver showing a significant expression of HCV core RNA and protein. The sub-replicon amplification caused no abnormality in development and growth of zebrafish larvae, but induced gene expression change similar to that in human hepatocytes. As the amplified core fluorescence in live zebrafish was detectable microscopically, it rendered us an advantage to select those with replicating sub-replicon for drug experiments. Ribavirin and oxymatrine, two known anti-HCV drugs, inhibited sub-replicon amplification in this model showing reduced levels of HCV core RNA and protein. Technically, this method had a good reproducibility and is easy to operate. Thus, zebrafish might be a model organism to host HCV, and this zebrafish/HCV (sub-replicon) system could be an animal model for anti-HCV drug screening and evaluation.

IRF8 and IRF3 cooperatively regulate rapid interferon-β induction in human blood monocytes

Robust and rapid induction of interferon-β (IFN-β) in monocytes after pathogenic stimulation is a hallmark of innate immune responses. Here, we reveal the molecular mechanism underlying this key property that is exclusive to human blood monocytes. We found that IFN-β was produced rapidly in primary human monocytes as a result of cooperation between the myeloid-specific transcription factor IRF8 and the ubiquitous transcription factor IRF3. Knockdown of IRF8 in monocytes abrogated IFN-β transcription, whereas reintroduction of IRF8 into the IRF8−/− 32Dcl3 murine myeloid cell line reinstated IFN-β transcription. Moreover, we provide evidence that IRF8 constitutively binds to the ETS/IRF composite element of the IFN-β promoter region together with PU.1 in vivo. Furthermore we uncovered a requirement for IRF3, a master regulator of IFN-β production, as a previously un-indentified interaction partner of IRF8. We mapped the protein-protein interacting regions of IRF3 and IRF8, and found that their interaction was independent of the DNA-binding domain and the IRF association domain of IRF8 and IRF3, respectively. Therefore, we propose a model for the rapid induction of IFN-β in monocytes, whereby IRF8 and PU.1 form a scaffold complex on the IFN-β promoter to facilitate the recruitment of IRF3, thus enabling rapid IFN-β transcription.