Construction and characterization of Genotype-3 hepatitis C virus replicon revealed critical genotype-3-specific polymorphism for drug resistance and viral fitness

Hepatitis C virus (HCV), a major causative agent of chronic hepatitis, is a positive-stranded RNA virus and has a high degree of genetic diversity due to its error-prone RNA-dependent RNA polymerase. Development of direct-acting antiviral agents (DAAs) has greatly improved the therapeutic outcome of chronic hepatitis C patients. However, naturally existing resistance-associated variants (RAVs) or occurrence of resistance-associated substitutions (RASs) in the HCV genome may impose a challenge to the long-term success of the DAA-based therapies. Genotype-3 HCV is the most difficult genotype to treat by DAAs, but the underlying molecular mechanisms remain to be explored. Here we developed a novel genotype-3a subgenomic replicon PR87A7 by screening a HCV cDNA pool amplified from a patient serum RNA. PR87A7 replicon displayed strong resistance to anti-NS3 DAAs, mainly owing to a genotype-3-specific polymorphism 168Q in NS3. Introduction of NS3 168Q into a genotype-2a JFH1 strain rendered resistance to anti-NS3 DAAs while greatly diminished the viral replication, and yet this fitness defect can be rescued by additional genotype-3-specific polymorphism. In conclusion, we developed a novel genotype-3a subgenomic replicon by a functional screening approach, and revealed genotype-3-specfic amino acid residues that confer resistance to anti-NS3 DAAs while retaining viral fitness.

The hidden impact of different Blastocystis genotypes on C-3 and IgE serum levels: a matter of debate in asthmatic Egyptian children

Blastocystis hominis is highly prevalent with respiratory allergies among Egyptian children. Yet, little is known about the possible immunological relationship. Aims of this study were to measure complement-3 (C-3), total and specific IgE to intestinal allergens in patients' serum regarding the identified B. hominis genotypes. In a cross-sectional study, three hundred children (150 asthmatics and 150 non asthmatics) participated in the study from both sexes, mean age 7.5 ± SD (3-4) years after a questionnaire administration. PCR-based genotyping of B. hominis selective in vitro cultivation was performed. C-3, total and specific IgE were all measured in patients' serum utilizing ELISA. Blastocystosis was detected in 100 out of 300 children, 65 (43.3%) out of 150 asthmatics and 35 (23.3%) out of 150 non-asthmatics. Vacuolar forms were the most prevalent in both direct wet mount and stool cultures. Forty (61.5%) out 65 asthmatics and 5 (14.2%) out of 35 non-asthmatics were ≥ 5 organisms/HPF. Sex and irritable bowel disease were statistically insignificant (p value < 0.05). Urticaria was coincided in 15.4% of asthmatics and 8.6% of non-asthmatics. Of 100 cases of blastocystosis, eighty-four were genotype-3 and sixteen were genotype-4. Out of these, 55 cases of genotype-3 and 6 cases of genotype-4 were asthmatics. Positive C-3 serum levels were in 46 (54.81%) of genotype-3 and 2 (12.5%) of genotype-4. High total IgE levels in 30 (35.7%) out of 84 cases of genotype-3 and 4 (25%) out of 16 cases of genotype-4. Positive specific IgE was in 25 (29.8%) of genotype-3 and 3 (18.75%) of genotype-4. Genotype-3 was of higher infection intensity (p value = 0.0001). In conclusion, B. hominis possess a hidden allergy triggering impact that can be obscured by simultaneous high (total and specific) IgE levels towards specific common intestinal allergens. Blastocystosis induces allergy by increasing C-3 serum levels in a genotype-dependent manner being higher in genotype-3. Virulence of genotype-3 seems to stand beyond increased parasite intensity and wide absorption of intestinal allergens that indirectly elevate IgE serum levels.

Early Experience of Sofosbuvir based Combination Therapy in "Real-Life" Cohort with Chronic Hepatitis-C Infection

INTRODUCTION

There is scarcity of data in literature regarding the treatment response with Sofosbuvir (SOF) based therapy in Indian patients with chronic Hepatitis-C Virus (HCV) infection.

AIM

This study was designed to observe initial treatment response to SOF based therapy in a "real-life" cohort of Indian patients with HCV infection.

MATERIALS AND METHODS

This is a prospective, observational and single center study. A total of 107 patients who were diagnosed with chronic HCV infection and received SOF based treatment between March 2015 and December 2015 were included. The patients were treated with either triple drug regimen [SOF, Ribavirin (RBV) and Pegylated Interferon-α (Peg IFN-α)] or dual drug regimen (SOF and RBV) for either 12 or 24 weeks. The virological responses were obtained at baseline and thereafter weekly (up to four weeks) till viral load became undetected during treatment.

RESULTS

A total of 107 patients who received SOF based therapy for chronic HCV infection were included in the study. Mean age of the patients was 48.7±10.7 years. Among included patients, 24 (22.4%) patients were treatment-experienced. Majority of the patients (n=69; 64.5%) were infected with HCV genotype-3. Except one patient, all the included patients achieved virological response up to week-4 of the treatment. There was statistically insignificant association between virological response (up to four week of the treatment) and severity of the disease (cirrhosis and non-cirrhosis) or treatment status (treatment-naïve and treatment-experienced), or HCV genotype (genotype-1 and 3).

CONCLUSION

The results of this observational study demonstrated rapid initial virological response of SOF based therapy in "real-life" cohort of Indian patients with chronic HCV infection. However, long-term follow-up data are needed to ensure the sustained antiviral efficacy of SOF based therapy.