Identificação de polimorfismos e mutações primárias de resistência aos inibidores de protease (NS3/NS4A) no vírus da hepatite C em pacientes com hepatite C crônica monoinfectados e coinfectados pelo vírus da imunodeficiência humana

Lisbôa Neto G. Characterization of NS3/NS4A polymorphisms and hepatitis C protease inhibitors resistance-associated mutations in hepatitis C virus monoinfected and human immunodeficiency virus coinfected patients [Thesis]. São Paulo: Faculdade de Medicina, Universidade de São Paulo; 2017. INTRODUCTION: Chronic hepatitis C is a major cause of liver disease worldwide. Hepatitis C vírus (HCV) and HIV coinfection is not uncommon due to similar transmission routes. Recently developed direct-acting antivirals drugs (DAAs) have increased the rate of SVR even in coinfected patients. HCV has a high replication rate and a lack of proofreading activity, leading to a greatly diverse viral population. Baseline spontaneously occurring resistance substitutions in the protease region may impair the rate of success in some protease inhibitors (PI) based regimens. OBJECTIVE: to determine the prevalence of naturally occurring polymorphisms and resistance associated variants to HCV PIs in mono and coinfected HCV HIV patients and to evaluate potential associations between amino acid substitutions in protease domain and clinical / virological features of those patients. METHODS: Clinical and epidemiological data were retrieved from medical records of 247 subjects in Brazil (135 HCV monoinfected and 112 HIV HCV coinfected patients). HCV-RNA was extracted from plasma and a fragment of 765 base pairs from the NS3 region was amplified and sequenced with Sanger-based technology. Fibrosis staging was assessed by non invasive score (FIB-4). RESULTS: Overall, 54 patients (21.9%) had at least one amino acid substitution in the NS3 region; only 14 patients (5.7%) harboured at least one resistance mutation (T54S, V55A, Q80R). Q80K mutation was not found in any sample. There was no difference between monoinfected and coinfected patients regarding the frequency of natural polymorphisms and resistance mutations. Variables independently associated with amino acid substitution were HCV subtype 1b, total bilirubin level > 1.5 ULN and albumin level < 3.5 g/dL. Advanced liver fibrosis (FIB-4 > 3.25) was not related to NS3 polymorphisms nor resistance associated variants. Examination of HCV protease nucleotide diversity revealed greater heterogeneity in subtype 1b than subtype 1a. Analysis of selective pressure did not reveal a greater quasispecies variability in advanced liver fibrosis group, being such finding consistent with a relatively conserved gene in this setting. CONCLUSION: Baseline HCV NS3 amino acid substitutions depicted herein were considered mostly natural polymorphisms with no clinical impact in a PI based therapy. The prevalence of resistance-associated substitutions was low and compatible with values reported by most national and international studies. HIV coinfection was not associated with a greater frequency of such substitutions in the studied sample. The NS3 region of genotype 1b was highly variable in relation to genotype 1a, highlighting geographic differences concerning HCV genetic profile. Descriptors: 1.Hepatitis C, chronic/epidemiology 2.Hepatitis C, chronic/therapy 3.HIV 4.Protease inhibitors 5.Drug resistance, viral 6.Cross-sectional studies