A influência dos polimorfismos nos genes interferons lambda 3 lambda 4 e ancestralidade genética na infecção crônica pelo vírus da hepatite c e na resposta ao tratamento em uma população miscigenada de Belém-Pará-Brasil

Abstract

Chronic infection by Hepatitis C virus is a global public health problem in which more than half of infected people evolves to chronicity and can progress to cirrhosis with its complications as well as hepatocellular carcinoma. This study aimed to describe the polymorphisms in genes IL-28B and IFNL4 in a population of Belém with chronic infection by hepatitis C because they can influence the therapeutic response and the natural history of this infection. Three hundred and sixty-six patients were attended at Santa Casa de Misericórdia do Pará Hospital, confirmed by RT-PCR and 243 controls. The SNPs studied were determined by PCR Real Time technique and ancestry was assessed using 48 INDEL markers validated for European, African and Indian parental populations. Contributions of African, European and Amerindian ancestry were found in patients and controls, respectively (0.06 vs 0.04), (0,58 vs 0.662) (0.275) vs (0.214). The frequencies of rs-860 C/C, C/T, T/T (C/T and T/T) in patients and controls were respectively: (21% vs 38%), 59% vs 48%), (19% vs 14%), (79% vs 62%). The rs-917 genotype frequencies in patients and controls showed no significance and genotype frequencies in ss-590 were similar to those in rs-860. As predictors of therapeutic response: female gender, age below 45 years old, hepatic fibrosis stage (F1F2), rs-917 genotype T/T, HCV RNA <600.000UI/ml and platelets levels ≥ 150 x104 / mm3. Therapeutic response was associated with the rs-917 T/T and its mutant allele in heterozygous or homozygous was associated with therapeutic failure and F3 F4. In conclusion, from the point of view of genetics, one nitrogenous base exchange on a particular chromosome leads to large repercussions on different studied populations interfering with aspects related to the response to therapy, natural course of HCV infection. This information could lead to individualized treatment with better prospects of responses, increased vigilance for certain patients more likely to progress to more advanced stages of fibrosis and hepatocellular carcinoma.