Multi-ancestry fine mapping of interferon lambda and the outcome of acute hepatitis C virus infection

Clearance of acute infection with hepatitis C virus (HCV) is associated with the chr19q13.13 region containing the rs368234815 (TT/ΔG) polymorphism. We fine-mapped this region to detect possible causal variants that may contribute to HCV clearance. First, we performed sequencing of IFNL1-IFNL4 region in 64 individuals sampled according to rs368234815 genotype: TT/clearance (N = 16) and ΔG/persistent (N = 15) (genotype-outcome concordant) or TT/persistent (N = 19) and ΔG/clearance (N = 14) (discordant). 25 SNPs had a difference in counts of alternative allele >5 between clearance and persistence individuals. Then, we evaluated those markers in an association analysis of HCV clearance conditioning on rs368234815 in two groups of European (692 clearance/1 025 persistence) and African ancestry (320 clearance/1 515 persistence) individuals. 10/25 variants were associated (P < 0.05) in the conditioned analysis leaded by rs4803221 (P value = 4.9 × 10−04) and rs8099917 (P value = 5.5 × 10−04). In the European ancestry group, individuals with the haplotype rs368234815ΔG/rs4803221C were 1.7× more likely to clear than those with the rs368234815ΔG/rs4803221G haplotype (P value = 3.6 × 10−05). For another nearby SNP, the haplotype of rs368234815ΔG/rs8099917T was associated with HCV clearance compared to rs368234815ΔG/rs8099917G (OR: 1.6, P value = 1.8 × 10−04). We identified four possible causal variants: rs368234815, rs12982533, rs10612351 and rs4803221. Our results suggest a main signal of association represented by rs368234815, with contributions from rs4803221, and/or nearby SNPs including rs8099917

Genetic basis for variation in plasma IL-18 levels in persons with chronic hepatitis C virus and human immunodeficiency virus-1 infections

Inflammasomes are multi-protein complexes integrating pathogen-triggered signaling leading to the generation of pro-inflammatory cytokines including interleukin-18 (IL-18). Hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infections are associated with elevated IL-18, suggesting inflammasome activation. However, there is marked person-to-person variation in the inflammasome response to HCV and HIV. We hypothesized that host genetics may explain this variation. To test this, we analyzed the associations of plasma IL-18 levels and polymorphisms in 10 genes in the inflammasome cascade. About 1538 participants with active HIV and/or HCV infection in three ancestry groups are included. Samples were genotyped using the Illumina Omni 1-quad and Omni 2.5 arrays. Linear regression analyses were performed to test the association of variants with log IL-18 including HCV and HIV infection status, and HIV RNA in each ancestry group and then meta-analyzed. Eleven highly correlated single-nucleotide polymorphisms (r²=0.98–1) in the IL-18-BCO2 region were significantly associated with log IL-18; each T allele of rs80011693 confers a decrease of 0.06 log pg ml⁻¹ of IL-18 after adjusting for covariates (rs80011693; rs111311302 β=−0.06, P-value=2.7 × 10⁻⁴). In conclusion, genetic variation in IL-18 is associated with IL-18 production in response to HIV and HCV infection, and may explain variability in the inflammatory outcomes of chronic viral infections

Risk Factors for Fatty Liver in the Multicenter AIDS Cohort Study

ObjectivesHuman immunodeficiency virus (HIV) infection and antiretroviral therapy (ART) may increase the risk of fatty liver disease. We determined the prevalence of and risk factors for fatty liver by comparing HIV-infected men with HIV-uninfected men who have sex with men in the Multicenter AIDS Cohort Study (MACS).MethodsIn 719 MACS participants who consumed less than three alcoholic drinks daily, fatty liver was defined as a liver-to-spleen attenuation ratio &lt;1 on noncontrast computed tomography (CT). We genotyped single nucleotide polymorphisms in the patatin-like phospholipase domain-containing 3 (PNPLA3) gene and in other genes previously associated with nonalcoholic fatty liver disease. Risk factors for fatty liver were determined using multivariable logistic regression.ResultsAmong 254 HIV-uninfected men and 465 HIV-infected men, 56% were White with median age 53 years and median body mass index 25.8 kg/m(2). The vast majority of HIV-infected men (92%) were on ART, and 87% of the HIV-infected men were treated with a nucleoside reverse transcriptase inhibitor for a median duration of 8.5 years. Overall, 15% of the cohort had fatty liver, which was more common in the HIV-uninfected compared with the HIV-infected men (19 vs. 13%, P=0.02). In multivariable analysis, HIV infection was associated with a lower prevalence of fatty liver (odds ratio (OR)=0.44, P=0.002), whereas a higher prevalence of fatty liver was seen in participants with PNPLA3 (rs738409) non-CC genotype (OR=2.06, P=0.005), more abdominal visceral adipose tissue (OR=1.08 per 10 cm(2), P&lt;0.001), and homeostatic model assessment of insulin resistance (HOMA-IR) ≥4.9 (OR=2.50, P=0.001). Among HIV-infected men, PNPLA3 (rs738409) non-CC genotype was associated with a higher prevalence of fatty liver (OR=3.30, P=0.001) and cumulative dideoxynucleoside exposure (OR=1.44 per 5 years, P=0.02).ConclusionsCT-defined fatty liver is common among men at risk for HIV infection and is associated with greater visceral adiposity, HOMA-IR, and PNPLA3 (rs738409). Although treated HIV infection was associated with a lower prevalence of fatty liver, prolonged exposure to dideoxynucleoside analogs is associated with higher prevalence

Risk Factors for Fatty Liver in the Multicenter AIDS Cohort Study

OBJECTIVES: Human immunodeficiency virus (HIV) infection and antiretroviral therapy (ART) may increase the risk of fatty liver disease. We determined the prevalence of and risk factors for fatty liver by comparing HIV-infected men with HIV-uninfected men who have sex with men in the Multicenter AIDS Cohort Study (MACS). METHODS: In 719 MACS participants who consumed less than three alcoholic drinks daily, fatty liver was defined as a liver-to-spleen attenuation ratio < 1 on noncontrast computed tomography (CT). We genotyped single nucleotide polymorphisms in the patatin-like phospholipase domain-containing 3 (PNPLA3) gene and in other genes previously associated with nonalcoholic fatty liver disease. Risk factors for fatty liver were determined using multivariable logistic regression. RESULTS: Among 254 HIV-uninfected men and 465 HIV-infected men, 56 % were White with median age 53 years and median body mass index 25.8 kg/m (2). The vast majority of HIV-infected men (92 %) were on ART, and 87 % of the HIV-infected men were treated with a nucleoside reverse transcriptase inhibitor for a median duration of 8.5 years. Overall, 15 % of the cohort had fatty liver, which was more common in the HIV-uninfected compared with the HIV-infected men (19 vs. 13 %, P= 0.02). In multivariable analysis, HIV infection was associated with a lower prevalence of fatty liver (odds ratio (OR) = 0.44, P= 0.002), whereas a higher prevalence of fatty liver was seen in participants with PNPLA3 (rs738409) non-CC genotype (OR = 2.06, P= 0.005), more abdominal visceral adipose tissue (OR = 1.08 per 10 cm(2), P< 0.001), and homeostatic model assessment of insulin resistance (HOMA-IR) ≥ 4.9 (OR = 2.50, P= 0.001). Among HIV-infected men, PNPLA3 (rs738409) non-CC genotype was associated with a higher prevalence of fatty liver (OR = 3.30, P= 0.001) and cumulative dideoxynucleoside exposure (OR = 1.44 per 5 years, P= 0.02). CONCLUSIONS: CT-defined fatty liver is common among men at risk for HIV infection and is associated with greater visceral adiposity, HOMA-IR, and PNPLA3 (rs738409). Although treated HIV infection was associated with a lower prevalence of fatty liver, prolonged exposure to dideoxynucleo side analogs is associated with higher prevalence

Admixture analysis of spontaneous hepatitis C virus clearance in individuals of African descent

Hepatitis C virus (HCV) infects an estimated 3% of the global population with the majority of individuals (75–85%) failing to clear the virus without treatment, leading to chronic liver disease. Individuals of African-descent have lower rates of clearance compared to individuals of European-descent and this is not fully explained by social and environmental factors. This suggests that differences in genetic background may contribute to this difference in clinical outcome following HCV infection. Using 473 individuals and 792,721 SNPs from a genome-wide association study (GWAS), we estimated local African ancestry across the genome. Using admixture mapping and logistic regression we identified two regions of interest associated with spontaneous clearance of HCV (15q24, 20p12). A genome-wide significant variant was identified on chromosome 15 at the imputed SNP, rs55817928 (P=6.18×10(−8)) between the genes SCAPER and RCN. Each additional copy of the African ancestral C allele is associated with 2.4 times the odds of spontaneous clearance. Conditional analysis using this SNP in the logistic regression model explained one-third of the local ancestry association. Additionally, signals of selection in this area suggest positive selection due to some ancestral pathogen or environmental pressure in African, but not in European populations

Genome-wide association study of hepatitis C virus- and cryoglobulin-related vasculitis.

The host genetic basis of mixed cryoglobulin vasculitis is not well understood and has not been studied in large cohorts. A genome-wide association study was conducted among 356 hepatitis C virus (HCV) RNA-positive individuals with cryoglobulin-related vasculitis and 447 ethnically matched, HCV RNA-positive controls. All cases had both serum cryoglobulins and a vasculitis syndrome. A total of 899 641 markers from the Illumina HumanOmni1-Quad chip were analyzed using logistic regression adjusted for sex, as well as genetically determined ancestry. Replication of select single-nucleotide polymorphisms (SNPs) was conducted using 91 cases and 180 controls, adjusting for sex and country of origin. The most significant associations were identified on chromosome 6 near the NOTCH4 and MHC class II genes. A genome-wide significant association was detected on chromosome 6 at SNP rs9461776 (odds ratio=2.16, P=1.16E-07) between HLA-DRB1 and DQA1: this association was further replicated in additional independent samples (meta-analysis P=7.1 × 10(-9)). A genome-wide significant association with cryoglobulin-related vasculitis was identified with SNPs near NOTCH4 and MHC Class II genes. The two regions are correlated and it is difficult to disentangle which gene is responsible for the association with mixed cryoglobulinemia vasculitis in this extended major histocompatibility complex region