Influência dos polimorfismos nos genes dos receptores TLR4 e TLR9 no desenvolvimento da fibrose hepática associada à infecção pelos vírus das hepatites B e Delta

Abstract

Introduction: Hepatitis B and Delta are diseases caused by hepatotropic viruses, with a high incidence in the Amazon basin region, where it is typical to find the genotype considered the most aggressive of Delta hepatitis and, according to the World Health Organization, it is the most serious form of chronic viral hepatitis for having faster progression to advanced stages of hepatic impairment and death. The analysis of single nucleotide polymorphisms (SNPs), which can affect the recognition functions of Toll-like receptors of innate immunity, and cytokines could explain the chronification processes during the infection caused by the hepatitis B and Delta viruses in the Amazon region. Objective: Describe the frequency of polymorphisms in the TLR4 (rs4986790 and rs4986791) and TLR9 (rs5743836 and rs187084) receptor genes, assess the influence of these polymorphisms on the development of liver fibrosis associated with infection by the Hepatitis B and Delta viruses, relating to the degree liver fibrosis, laboratory and clinical changes, expression of TLR4 and TLR9 in monocytes, as well as with the levels of cytokines IL-2, IL-4, IL-6, IL-10, TNF and IFN-γ. Material and methods: The study population consisted of 77 patients diagnosed with HBV/HDV viruses treated at the Fundação de Medicina Tropical Doutor Heitor Vieira Dourado and 137 blood donors who attended the Fundação Hospitalar de Hematologia e Hemoterapia do Amazonas, both in the city of Manaus/AM. Fibrosis staging was performed using the FIB-4 index and METAVIR classification; serum levels of cytokines were analyzed using the CBA Flow Cytometry technique; the characterization of the polymorphisms was obtained by PCR-RFLP; and the expression of TLR4 and TLR9 in monocytes by flow cytometry. Results: In HDV+ patients with >F2 fibrosis, there is a significant increase in serum levels of Th1 profile cytokines: IL-6 when compared to those of fibrosis ≤F2 (in live, p = 0,0142; and in confirmed death, p = 0,0317); and TNF in the presence of the C/T genotype in relation to the C/C genotype of TLR9 -1486 C/T (p = 0,0067). In HDV+ patients with ≤F2 fibrosis, cytokines that reached significantly elevated serum levels were: IL-6 (Th1), in carriers of the A/A genotype compared to those of the A/G genotype of TLR4 A299G (p = 0,0242); and IL-10 (regulatory), in individuals of T/T and T/C genotypes in relation to those of C/C genotype of TLR9 -1237 T/C genotype (p = 0,0098 and p = 0,0335, respectively). Conclusion: These results infer that there is possibly a balancing of the immune response between the Th1 profile (IL-6) and the regulatory profile (IL-10) in HDV+ fibrosis patients ≤F2 so that there is no progression to advanced fibrosis.