Interleukin 28B-related polymorphisms: A pathway for understanding hepatitis C virus infection?

The association of LMP7 and TAP2 gene polymorphisms with treatment response to interferon/ribavirin in patients with genotype 1 chronic hepatitis C

Previous studies have highlighted the important role of genes related to antigen presentation in the spontaneous clearance of hepatitis C virus. The present study aimed to explore the association between TAP, LMP and tapasin gene polymorphism and treatment response in chronic hepatitis C virus (CHC) patients. Six single nucleotide polymorphisms in TAP, LMP and tapasin genes were genotyped among 352 Chinese genotype 1 CHC patients with pegylated interferon-α and ribavirin (pegIFN-α/RBV) treatment. There were 232 cases achieving sustained virological response (SVR), which yielded an SVR rate of 65.9%. LMP7 rs2071543 variant genotypes [additive model: odds ratio (OR), 0.52; 95% confidence interval (CI), 0.33-0.82; P=0.005] and TAP2 rs1800454 variant genotypes (additive model: OR, 0.66; 95% CI, 0.45‑0.98; P=0.039) were suggested to decrease the possibility of achieving an SVR. After conducting combined effect analysis of rs2071543 and rs1800454, the authors found that the SVR rate was lower among patients carrying more unfavorable rs1800454-A and rs2071543-A alleles, and the SVR rate of carrying 3-4 alleles was 20%. In addition, carrying two unfavorable alleles led to significantly decreased possibility for SVR (OR, 0.30; 95% CI, 0.14-0.61; P=0.001). Multivariate stepwise analysis indicated that rs2071543, rs1800454, glucose, α-fetoprotein, platelets and baseline viral load were risk factors of SVR that were independent of each other. The area under the curve (AUC) consisting of all the above factors produced an AUC of 0.704 (95% CI, 0.647‑0.761; P<0.001). The line charts indicated that the drop in viral load was significantly faster in GG patients than in GC/CC patients during the whole therapy, which was in accordance with the decline of viral load in rs2071543. The present study illustrated that the carriage of LMP7 rs2071543-AA and TAP2 rs1800454-AA had a negative effect on treatment response to pegIFN-α/RBV among genotype 1 patient with CHC in a Chinese Han population.

IL28B gene polymorphisms and Th1/Th2 cytokine levels might be associated with HTLV-associated arthropathy

The present study is the first investigation of the association between single nucleotide polymorphisms (SNPs - rs8099917, rs12979860 and rs8103142) of the IL28B gene and the development of human T-lymphotropic virus (HTLV)-associated arthropathy (HAA). Individuals with HAA exhibited low interleukin (IL) 6 (p<0.05) and high IL-10 (p<0.05) levels compared with asymptomatic patients. TNF-α/CD4(+) T cell count, TNF-α/CD8(+) T cell count and IFN-γ/proviral load positively correlated in asymptomatic patients. The allelic and genotypic frequencies did not differ between patients with HAA and asymptomatic patients. Seven haplotypes were detected in the investigated population, with haplotype CCT (p<0.05) being the most frequent among the HTLV-infected individuals, while haplotype TTG (p<0.05) was detected in the group with HAA only. Compared with asymptomatic patients, individuals with HAA and genotype TT (rs8099917) exhibited larger numbers of CD8(+) T cells (p<0.05) and higher proviral load levels (p<0.05). Those patients with HAA and genotypes CC (rs12979860) and TT (rs8103142) exhibited high TNF-β (p<0.05) and IFN-γ (p<0.05) levels. Those patients with HAA and genotype CT/TT (rs12979860) exhibited high IL-10 levels (p<0.05). These results suggest that haplotypes CCT and TTG might be associated with susceptibility to HTLV infection and progression to HAA, respectively. Genotype TT (rs8099917) might be a risk factor for elevation of the proviral load and CD8(+) T cell count. In addition, genotypes CC (rs12979860) and TT (rs8103142) seem to be associated with increased TNF-β and IFN-γ levels.

Association of cytokine gene polymorphisms with hepatitis C virus infection in a population from Rio de Janeiro, Brazil

Background

The host immune response is an important indicator of the outcome of hepatitis C virus (HCV) infection and disease progression. The aim of this study was to explore cytokine gene polymorphisms as a candidate for susceptibility to persistent HCV infection or HCV spontaneous clearance in a population from Rio de Janeiro, Brazil.

Methods

Genetic polymorphisms in the cytokines, tumor necrosis factor-alpha (−308), transforming growth factor-beta 1 (codons 10 and 25), interleukin-10 (IL-10; −1082 and −592), IL-6 (−174), and interferon-gamma (+874) were analyzed by polymerase chain reaction sequence-specific primers in 245 patients with chronic hepatitis C (CHC), 41 spontaneous recovery (SR) patients, and 189 healthy volunteers. Further, polymorphisms in IL-28B (rs12979860, rs12980275, and rs8099917) were assessed by real-time polymerase chain reaction in all groups.

Results

The IL-28B rs12979860 CC and rs12980275 AA genotypes were significantly associated with SR of HCV infection and response to therapy, whereas the C allele of IL-6 (−174) was associated with protection to CHC. A multivariate analysis showed that the male sex and IL-28B rs12979860 CT and TT and transforming growth factor-beta 1 (codon 10) TC genotypes were factors associated with CHC. Additionally, IL-6 (−174) C allele was increased in SR patients compared with patients with CHC.

Conclusion

IL-28B polymorphisms are associated with spontaneous clearance of HCV and response to therapy in a Brazilian population. Also, IL-6 (−174) C allele is involved in SR and decreased inflammation scores.

IL28B gene polymorphism SNP rs8099917 genotype GG is associated with HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) in HTLV-1 carriers

BACKGROUND

The polymorphisms of IL28B have been described as important in the pathogenesis of infections caused by some viruses. The aim of this research was to evaluate whether IL28B gene polymorphisms (SNP rs8099917 and SNP rs12979860) are associated with HAM/TSP.

METHODS

The study included 229 subjects, classified according to their neurological status in two groups: Group I (136 asymptomatic HTLV-1 carriers) and Group II (93 HAM/TSP patients). The proviral loads were quantified, and the rs8099917 and rs12979860 SNPs in the region of IL28B-gene were analyzed by StepOnePlus Real-time PCR System.

RESULTS

A multivariate model analysis, including gender, age, and HTLV-1 DNA proviral load, showed that IL28B polymorphisms were independently associated with HAM/TSP outcome in rs12979860 genotype CT (OR = 2.03; IC95% = 0.96-4.27) and in rs8099917 genotype GG (OR = 7.61; IC95%  = 1.82-31.72).

CONCLUSION

Subjects with SNP rs8099917 genotype GG and rs12979618 genotype CT may present a distinct immune response against HTLV-1 infection. So, it seems reasonable to suggest that a search for IL28B polymorphisms should be performed for all HTLV-1-infected subjects in order to monitor their risk for disease development; however, since this is the first description of such finding in the literature, we should first replicate this study with more HTLV-1-infected persons to strengthen the evidence already provided by our results.

Strategies to manage hepatitis C virus (HCV) disease burden

The number of hepatitis C virus (HCV) infections is projected to decline while those with advanced liver disease will increase. A modeling approach was used to forecast two treatment scenarios: (i) the impact of increased treatment efficacy while keeping the number of treated patients constant and (ii) increasing efficacy and treatment rate. This analysis suggests that successful diagnosis and treatment of a small proportion of patients can contribute significantly to the reduction of disease burden in the countries studied. The largest reduction in HCV-related morbidity and mortality occurs when increased treatment is combined with higher efficacy therapies, generally in combination with increased diagnosis. With a treatment rate of approximately 10%, this analysis suggests it is possible to achieve elimination of HCV (defined as a >90% decline in total infections by 2030). However, for most countries presented, this will require a 3-5 fold increase in diagnosis and/or treatment. Thus, building the public health and clinical provider capacity for improved diagnosis and treatment will be critical.