[Genetics and hepatitis C treatment: towards a personalized treatment?]

Profile of HIV subtypes in HIV/HBV- and HIV/HCV-coinfected patients in Southern Brazil

INTRODUCTION:

HIV and viral hepatitis infections are major causes of chronic disease worldwide and have some similarities with regard to routes of transmission, epidemiology, front barriers faced during access of treatment, and strategies for a global public health response. The objective was to describe the HIV-1 subtypes, viral tropism and single-nucleotide polymorphisms (SNPs) of interleukin 28B (IL28B) from a case series of HIV/viral hepatitis coinfected patients from southern Brazil.

METHODS:

Clinical and epidemiological data were evaluated by a review of medical records. Periodic blood draws were taken to determine the viral and host characteristics.

RESULTS:

This study included 38 patients with HIV/HBV or HIV/HCV coinfection; the median age was 49 years. Thirty-seven (97.4%) were on antiretroviral therapy, 32 (84.2%) had an undetectable viral load, a median CD4+ T-cell count of 452 cells/mm3. HIV-1 subtyping showed 47.4 and 31.6% of patients with subtypes C and B, respectively. Analysis of viral co-receptor usage showed a predominance of the R5 variant (64.7%), with no significant difference between the subtypes. Twenty patients with HIV/HCV coinfection were eligible to receive HCV therapy with pegylated-interferon-alpha plus ribavirin, and 10/20 (50%) of them achieved sustained virological response. SNPs of IL28B were evaluated in 93.3% of patients with HIV/HCV coinfection, and 17 (60.7%) presented the CC genotype.

CONCLUSIONS:

In the present case series, a higher frequency of HIV subtype C was found in coinfected patients. However such findings need to be prospectively evaluated with the inclusion of data from regional multicenter analyses.

IL28B gene polymorphisms in mono- and HIV-coinfected chronic hepatitis C patients

Introduction: Single-nucleotide polymorphisms (SNPs) associated with hepatitis C virus (HCV) clearance were identified near the IL28B gene. Coinfection by the human immunodeficiency virus (HIV) influences the course of HCV contributing to liver damage. Nevertheless, little is known about the relationship between these SNPs and HCV/HIV coinfection. Our aim was to estimate the frequencies of the allelic and genotypic variants of the IL28B polymorphisms rs12979860 (C/T) and rs8099917 (T/G) and their possible association with the establishment of HCV infection.

Methodology: A total of 199 non-infected controls and 230 patients with chronic hepatitis C, including 53 coinfected with HIV, participated in the study. Genotyping consisted of polymerase chain reaction and subsequent analysis of the restriction patterns resulting from exposure to endonucleases.

Results: Among the controls with established results, 47.4% (90/190) exhibited the rs12979860 CC genotype, 43.7 CT, and 8.9% TT, whereas 29.1% (66/227), 51.5%, and 19.4% of the patients exhibited the CC, CT, and TT genotypes, respectively. With respect to rs8099917, 66.8% (133/199) of the controls exhibited the TT genotype, 31.2% TG, and 2.0% GG, whereas 56.1% (129/230), 40.9%, and 3.0% of the patients exhibited the TT, TG, and GG genotypes, respectively.

Conclusion: The frequencies of the rs12979860 C allele and CC genotype and of the rs8099917 T allele and TT genotype were significantly higher among controls compared with patients, thus confirming the suggested protective effect against HCV infection. No significant difference was observed in the genotype and allelic distributions between the mono- and coinfected patients.

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

AIM

To analyze the role of rs12979860 and rs8099917 polymorphisms in hepatitis C virus (HCV) genotype 1 infection of Brazilians.

METHODS

A total of 145 adult patients diagnosed with genotype 1 chronic hepatitis C (CHC) who had completed a 48-wk regimen of pegylated-interferon α-2a or -2b plus ribavirin combination therapy were recruited from six large urban healthcare centers and 199 healthy blood donors (controls) from a single site between January 2010 and January 2012. Data on the patients' response to treatment was collected. Polymerase chain reaction-restriction fragment length polymorphism genotyping of the interleukin (IL)28B gene fragment encompassing the single nucleotide polymorphisms (SNPs) rs12979860 (C/T) and rs8099917 (T/G) was carried out for 79 of the CHC patients and 199 of the controls. Bi-directional amplicon sequencing of the two SNPs was carried out for the remaining 66 CHC patients.

RESULTS

SNP rs12979860 genotyping was successful in 99.5% of the controls and 97.2% of the CHC patients, whereas the SNP rs8099917 genotyping was successful in 95.5% of the controls and 100% of the CHC patients. The genotype and allele distributions for both rs12979860 and rs8099917 were significantly different between the control and CHC patient groups, with significantly higher genotype frequencies of CC and TT in the controls (P = 0.037 and 0.046, respectively) and of TT and GG in the CHC patients (P = 0.0009 and 0.0001, respectively). Analysis of the CHC patients who achieved sustained virological response (SVR) to treatment (n = 55) indicated that the rs12979860 C allele and CC genotype were predictors of SVR (P = 0.02). No significant correlation was found between rs8099917 genotypes and treatment response, but carriers of the T allele showed significantly higher rates of SVR (P = 0.02). Linkage disequilibrium analysis of the group that achieved SVR showed a significant association between rs12979860 and rs8099917 (P = 0.07).

CONCLUSION

The higher allele frequency of rs12979860 C and rs8099917 T observed in non-HCV-infected individuals may indicate a potential protective role for these IL28B-related polymorphisms.

A straightforward genotyping of the relevant IL28B SNPs for the prediction of hepatitis C treatment outcome

A sustained virological response is not achieved by a significant proportion of chronic hepatitis C patients treated with interferon-based regimens. Due to the associated side effects and high costs, therapy response markers have been thoroughly sought. Two Single Nucleotide Polymorphisms (SNPs), rs12979860 and rs8099917, which are located upstream from the IL28B gene, have been remarkably described to have a strong association with treatment efficacy. The aim of this study was to develop a straightforward method for genotyping such polymorphisms. A Polymerase Chain Reaction (PCR) followed by enzymatic restriction of amplicons was established for SNPs genotyping. Online computation resources were employed for retrieving reference sequences, such as the selection of oligonucleotides and restriction enzymes. Two pairs of primers were designed and validated for the amplification of segments encompassing rs12979860 (694bp) and rs8099917 (496bp) with common thermocycling parameters. The endonucleases Hpy166II and BsrDI were selected and used for allelic discrimination related to rs12979860 (C/T) and rs8099917 (T/G), respectively. The expected electropherotypes were confirmed for all possible genotypes in 75 blood samples. In addition, the results were validated by sequencing. The method constitutes a simple and reliable assay, which may be readily available for genotyping of rs12979860 and rs8099917 in laboratories that support hepatitis C treatment centers.