Demographics, socio-behavioral factors, and drug use patterns: what matters in spontaneous HCV clearance?

Sociodemographic and clinical characteristics of persons who experienced spontaneous hepatitis C viral clearance

Background

In the United States Hepatitis C virus (HCV) viral clearance is estimated to range between 20 and 30%. The objective of this study was to estimate the frequency of HCV clearance and identify correlates of viral clearance among patients newly identified as HCV antibody positive in a large urban health system in Los Angeles, California.

Methods

We identified patients between November 2015 and September 2017 as part of a newly implemented HCV screening and linkage-to-care program at University of California Los Angeles (UCLA) Health System. All patients were eligible for screening, though there were additional efforts to screen patients born between 1945 and 1965. We reviewed Medical records to categorize anti-HCV antibody positive patients as having spontaneously cleared HCV infection (HCV RNA not detected) or not (HCV RNA detected). We excluded those with a prior history of anti-HCV positivity or history of HCV treatment. We compared differences between those with and without detectable HCV RNA using chi-square test, Fisher’s exact test, and t-test as appropriate. We assessed factors associated with HCV clearance using logistic regression analysis.

Results

Among the 320 patients included in this study, 56% were male. Baby boomers (52–72 years of age) comprised the single largest age group (62%). We found spontaneous HCV clearance in 58% (n = 185). HCV viral clearance was slightly higher among women as compared to men (63% vs. 53%; p value = 0.07) and varied by race/ethnicity: clearance among Blacks/African Americans was 37% vs. 58% among whites (p value = 0.02). After adjusting for age, race/ethnicity, and sex we found that those diagnosed with chronic kidney disease had a tendency of decreased HCV viral clearance (adjusted OR = 0.34; 95% CI 0.14–1.03).

Conclusion

Of those patients newly identified as anti-HCV positive, 58% had cleared HCV virus, while the rest showed evidence of active infection. In addition, we found that clearance varied by race/ethnicity and clinical characteristics.

Assessing hepatitis C spontaneous clearance and understanding associated factors-A systematic review and meta-analysis

New advances in the treatment of hepatitis C provide high levels of sustained viral response but their expense limits availability in publicly funded health systems. The aim of this review was to estimate the proportion of patients who will spontaneously clear HCV, to identify factors that are associated with clearance and to support better targeting of directly acting antivirals. We searched Ovid EMBASE, Ovid MEDLINE and PubMed from 1 January 1994 to 30 June 2015 for studies reporting hepatitis C spontaneous clearance and/or demographic, clinical and behavioural factors associated with clearance. We undertook meta-analyses to estimate the odds of clearance for each predictor. Forty-three studies met the inclusion criteria, representing 20 110 individuals, and 6 of these studies included sufficient data to estimate spontaneous clearance. The proportion achieving clearance within 3, 6, 12 and 24 months following infection were, respectively, 19.8% (95% CI: 2.6%-47.5%), 27.9% (95% CI: 17.2%-41.8%), 36.1% (95% CI: 23.5%-50.9%) and 37.1% (95% CI: 23.7%-52.8%). Individuals who had not spontaneously cleared by 12 months were unlikely to do so. The likelihood of spontaneous clearance was lower in males and individuals with HIV co-infection, the absence of HBV co-infection, asymptomatic infection, black or nonindigenous race, nongenotype 1 infection, older age and alcohol or drug problems. This study suggests that patients continue to spontaneously clear HCV for at least 12 months following initial infection. However, injecting drug users are comparatively less likely to achieve clearance; thus, they should be considered a priority for early treatment given the continuing risks that these individuals pose for onwards transmission.

Association of killer cell immunoglobulin-like receptors with spontaneous clearance of hepatitis C virus in the Chinese population

BACKGROUND

Natural killer (NK) cells are critical components in innate immune response to viral infection. Killer cell immunoglobulin-like receptors (KIRs) are involved in regulating the balance of activation or inhibitory function of NK cells. However, the association of KIRs with the spontaneous clearance of hepatitis C virus (HCV) remains unclear in the Chinese population.

STUDY DESIGN AND METHODS

A total of 407 HCV-seropositive voluntary blood donors were recruited, including 203 with spontaneous viral clearance and 204 with chronic infection. The presence of KIR genes was detected individually by polymerase chain reaction with sequence-specific primers. Data of HLA and interleukin-28B (IL28B) genotypes were extracted from our previous study.

RESULTS

Our results showed that KIR2DL2, 2DS2, 2DL2/2DL3, and 2DL5A-/2DL5B+ were more frequent in subjects with HCV clearance than those with chronic infection (odds ratio [OR], 1.640, p = 0.034; OR, 1.664, p = 0.032; OR, 1.636, p = 0.040; and OR, 2.601, p = 0.012, respectively). Multivariate logistic regression analysis showed that KIR2DL5A-/2DL5B+ associated with HCV clearance (OR, 2.448, p = 0.027), independent of sex, IL28B, and other KIRs. In contrast, KIR2DL3/2DL3 (OR, 0.610, p = 0.034) as well as 2DL3/2DL3+HLA-C1 or C1C1 (OR, 0.580, p = 0.017; and OR, 0.639, p = 0.025, respectively) was found associated with chronic HCV infection. The presence of the homozygous KIR2DL3 with or without its HLA ligand increased the OR of developing chronic HCV infection in the context of IL28B.

CONCLUSIONS

In this study we identified KIR2DL5A-/2DL5B+ associated with HCV spontaneous clearance, while KIR2DL3/2DL3, 2DL3/2DL3+HLA-C1, or C1C1 associated with chronic infection. Our study highlighted the fact that the roles of KIR and KIR-HLA contributed to the control of HCV infection by innate immune responses.

A Biomolecular Network Driven Proteinic Interaction in HCV Clearance

Hepatitis C virus infection causes chronic liver disease that leads to cancer-related mortality. Presently around 30% of the HCV (infected) affected population get rid of the infection through spontaneous disease clearance. This phenomenon is conducted by a set of reported immune candidate genes. Hence, this study focuses only on these immune-response related genes with aid of network approach, where the idea is to disseminate the network for better understanding of key functional genes and their transcription control activity. Based on the network analysis the IFNG, TNF, IFNB1, STAT1, NFKB1, STAT3, SOCS1, and MYD88 genes are prioritized as hub genes along with their common transcription factors (TFs), IRF9, NFKB1, and STAT1. The dinucleotide frequency of TF binding elements indicated GG-rich motifs in these regulatory elements. On the other hand, gene enrichment report suggests the regulation of response to interferon gamma signaling pathway, which plays central role in the spontaneous HCV clearance. Therefore, our study tends to prioritize the genes, TFs, and their regulatory pathway towards HCV clearance. Even so, the resultant hub genes and their TFs and TF binding elements could be crucial in underscoring the clearance activity in specific populations.

HBV/HCV co-infection is associated with a high level of HCV spontaneous clearance among drug users and blood donors in China

Understanding the biology of spontaneous clearance of hepatitis C virus (HCV) infection could lead to improved strategies to prevent the sequelae associated with chronic HCV infection. Chronic infections with hepatitis virus are very common in China, but the factors associated with spontaneous clearance of HCV have not been adequately studied. We evaluated the spontaneous clearance of HCV among 1918 drug users and 1526 HCV-seropositive blood donors in Guangzhou, China. Among participants who were co-infected with hepatitis B virus (HBV), 41.38% of drug users and 39.47% of blood donors had cleared their HCV infection without antiviral therapy compared to 9.41% of drug users and 16.73% of blood donors who were mono-infected with a single virus (P<.01). The proportion of subjects who had cleared their HCV infection was significantly greater in the co-infected subjects whose serum HBV DNA was greater than 2000IU/mL than those with lower levels. A multiple logistic regression analysis found female gender, IL28B rs8099917 TT genotype, HBV co-infection and blood donors (vs drug users) associated with increased spontaneous clearance of HCV infection. Although acute HCV infections are common in China, the incidence of chronic HCV may be reduced among the high prevalence of chronic HBV and IL28B genotypes associated with spontaneous clearance of HCV in Chinese populations.

The effects of alcohol on spontaneous clearance of acute hepatitis C virus infection in females versus males

BACKGROUND

Approximately one quarter of persons exposed to hepatitis C virus (HCV) will spontaneously clear infection. We undertook this study to investigate the impact of alcohol on likelihood of HCV spontaneous viral clearance stratified by sex groups.

METHODS

Pooled data from an international collaboration of prospective observational studies of incident HIV and HCV infection in high-risk cohorts (the InC3 Study) was restricted to 411 persons (or 560.7 person-years of observation) with documented acute HCV infection and data regarding alcohol use. The predictor of interest was self-reported alcohol use at or after estimated date of incident HCV infection and the outcome was HCV spontaneous clearance. Sex stratified Cox proportional hazards models were used to evaluate the association between alcohol and spontaneous clearance, adjusting for age, race/ethnicity, and IFNL4 genotype.

RESULTS

The median age was 28.5 years, 30.4% were women, 87.2% were white, and 71.8% reported alcohol use at or after incident infection. There were 89 (21.6%) cases of spontaneous clearance observed, 39 (31.2%) among women and 50 (17.5%) in men (p<0.01). Overall, spontaneous clearance occurred less frequently among participants who drank alcohol compared to those who did not drink (18.9% v. 28.5%, p=0.03). After adjustment for other covariates, alcohol was significantly and independently associated with lower relative hazards for spontaneous clearance of HCV in women (AHR=0.35; 95% CI: 0.19-0.66; p=0.001) but not in men (AHR=0.63; 95% CI: 0.36-1.09; p=0.10).

CONCLUSION

Results indicate that abstaining from drinking alcohol may increase the likelihood of spontaneous clearance among women.

Spontaneous viral clearance of hepatitis C virus (HCV) infection among people who inject drugs (PWID) and HIV-positive men who have sex with men (HIV+ MSM): a systematic review and meta-analysis

Background

Hepatitis C virus (HCV) infection causes significant morbidity and mortality among people who inject drugs (PWID) and HIV+ men who have sex with men (MSM). Characterizing spontaneous viral clearance of HCV infection among PWID and HIV+ MSM is important for assessing the burden of disease and treatment strategies in these populations.

Methods

Electronic and other searches of medical literature were conducted. Reports were eligible if they presented original data from upper-middle- and high-income countries on laboratory-confirmed HCV infection and spontaneous viral clearance among PWID or HIV+ MSM. Pooled estimates of spontaneous viral clearance were generated using fixed-effect and random-effects models. Meta-regression examined potential predictors related to individual characteristics and research methodology.

Results

The meta-analysis estimated that spontaneous viral clearance occurs in 24.4 % of PWID and 15.4 % of HIV+ MSM. In univariate meta-regression among PWID, male sex and age were significantly associated with spontaneous viral clearance, and in multivariate analysis, male sex and HIV positivity were predictors of spontaneous viral clearance; among HIV+ MSM no variables were found to affect spontaneous viral clearance.

Conclusion

The variability in estimates of spontaneous viral clearance between HIV+ MSM and PWID suggests the impact of HIV co-infection and HCV re-infection. Due to limited data on additional factors that may affect the natural history of HCV, more research is needed to further understand spontaneous viral clearance in these risk groups.

Protocol registration

The protocols for the PWID and HIV+ MSM research were registered with PROSPERO (CRD42014008805; CRD42013006462).

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1807-5) contains supplementary material, which is available to authorized users.

The Associations of HLA-A*02:01 and DRB1*11:01 with Hepatitis C Virus Spontaneous Clearance Are Independent of IL28B in the Chinese Population

Spontaneous clearance of hepatitis C virus (HCV) occurs in 10-40% of the infections. Specific human leukocyte antigen (HLA) alleles have been identified in associating with HCV clearance. However, data on the association of HLA with the spontaneous clearance of HCV are scarce in the Chinese population. In the current study we studied the HLA class I and class II genes in 231 Chinese voluntary blood donors who had cleared HCV infection spontaneously compared to 429 subjects with chronic HCV infections. We also studied their IL28B SNP (rs8099917) genotype, since a number of investigators have found a strong association of IL28B with spontaneous or treatment induced HCV clearance. We found that HLA-A*02:01 and DQB1*05:02 distributed differently between the two groups after Bonferroni correction (odds ratio [OR] = 1.839, Pc = 0.024 and OR = 0.547, Pc = 0.016, respectively). Multivariate logistic regression analysis suggested that A*02:01 and DRB1*11:01 (OR = 1.798, P = 0.008 and OR = 1.921, P = 0.005, respectively) were associated with HCV spontaneous clearance, independent of age, gender and IL28B polymorphism. We concluded that in the Chinese population, HLA-A*02:01 and DRB1*11:01 might be associated with the host capacity to clear HCV independent of IL28B, which suggesting that the innate and adaptive immune responses both play an important role in the control of HCV.

Liver mortality attributable to chronic hepatitis C virus infection in Denmark and Scotland--using spontaneous resolvers as the benchmark comparator

Liver mortality among individuals with chronic hepatitis C (CHC) infection is common, but the relative contribution of CHC per se versus adverse health behaviors is uncertain. We explored data on spontaneous resolvers of hepatitis C virus (HCV) as a benchmark group to uncover the independent contribution of CHC on liver mortality. Using national HCV diagnosis and mortality registers from Denmark and Scotland, we calculated the liver mortality rate (LMR) for persons diagnosed with CHC infection (LMRchronic ) and spontaneously resolved infection (LMRresolved ), according to subgroups defined by age, sex, and drug use. Through these mortality rates, we determined subgroup-specific attributable fractions (AFs), defined as (LMRchronic - LMRresolved )/LMRchronic , and then calculated the total attributable fraction (TAF) as a weighted average of these AFs. Thus, the TAF represents the overall fraction (where 0.00 = not attributable at all; and 1.00 = entirely attributable) of liver mortality attributable to CHC in the diagnosed population. Our cohort comprised 7,005 and 21,729 persons diagnosed with HCV antibodies in Denmark and Scotland, respectively. Mean follow-up duration was 6.3-6.9 years. The TAF increased stepwise with age. It was lowest for death occurring at <45 years of age (0.21 in Denmark; 0.26 in Scotland), higher for death occurring at 45-59 years (0.69 in Denmark; 0.69 in Scotland), and highest for death at 60+years (0.92 in Denmark; 0.75 in Scotland). Overall, the TAF was 0.66 (95% confidence interval [CI]: 0.55-0.78) in Denmark and 0.55 (95% CI: 0.44-0.66) in Scotland.

CONCLUSIONS

In Denmark and Scotland, the majority of liver death in the CHC-diagnosed population can be attributed to CHC-nevertheless, an appreciable fraction cannot, cautioning that liver mortality in this population is a compound problem that can be reduced, but not solved, through antiviral therapy alone.

Baseline HCV Antibody Prevalence and Risk Factors among Drug Users in China's National Methadone Maintenance Treatment Program

BACKGROUND

Hepatitis C virus (HCV) is the most common viral infection among injecting drug users worldwide. We aimed to assess HCV antibody prevalence and associated risk factors among clients in the Chinese national methadone maintenance treatment (MMT) program.

METHODS

Data from 296,209 clients who enrolled in the national MMT program between March 2004 and December 2012 were analyzed to assess HCV antibody prevalence, associated risk factors, and geographical distribution.

RESULTS

Anti-HCV screening was positive for 54.6% of clients upon MMT entry between 2004 and 2012. HCV antibody prevalence at entry declined from 66.8% in 2005 to 45.9% in 2012. The most significant predictors of HCV seropositivity were injecting drug use (adjusted odds ratio [AOR]: 8.34, 95% confidence interval [CI]: 8.17-8.52, p<0.0001) and a history of drug use ≥9 years (AOR: 2.01, 95% CI: 1.96-2.06, p<0.0001). Being female, of Uyghur or Zhuang ethnicity, and unmarried were identified as demographic risk factors (all p-values<0.0001). Of the 28 provincial-level divisions included in the study, we found that 5 divisions had HCV antibody prevalence above 70% and 20 divisions above 50%. The HCV screening rate within 6 months after MMT entry greatly increased from 30.4% in 2004 to 93.1% in 2012.

CONCLUSIONS

The current HCV antibody prevalence remains alarmingly high among MMT clients throughout most provincial-level divisions in China, particularly among injecting drug users and females. A comprehensive prevention strategy is needed to control the HCV epidemic among MMT clients in China.

Prevalence of Hepatitis C among Egyptian Children with Sickle Cell Disease and the Role of IL28b Gene Polymorphisms in Spontaneous Viral Clearance

Background and Objectives

Hepatitis C virus (HCV) is a major health problem in Egypt with its prevalence estimated to be 14.7% among the general population in 2008. Patients receiving frequent blood transfusions like those with sickle cell disease (SCD) are more exposed to the risk of acquiring HCV. IL28B gene polymorphisms have been associated with spontaneous HCV clearance. This study aims to determine the prevalence of HCV infection among children with SCD and to investigate the relation between IL28B gene polymorphisms and spontaneous HCV clearance.

Methods

Seventy SCD patients were screened for HCV antibody. HCV-positive patients were tested for the level of HCV RNA using quantitative real-time PCR. IL28B polymorphisms (rs 12979860 SNP and rs 12980275 SNP) were detected using TaqMan QRT-PCR and sequence-specific primers PCR respectively.

Results

Sixteen patients (23%) were HCV antibody positive, 9 of them (56.3%) had undetectable HCV RNA in serum, and 7 (43.7%) had persistent viremia. Genotypes CC/CT/TT of rs12979860 were found in 30 (42.9%), 29 (41.4%) and 11 (15.7%) patients and rs12980275 AA/AG/GG were found in 8 (11.4%), 59 (84.3%) and 3 (4.3%) patients. There was no significant difference in the frequency of IL28B (rs 12979860 and rs12980275) genotypes among HCV patients who cleared the virus and those with persistent viremia (p=0.308 and 0.724 respectively).

Conclusion

Egyptian SCD patients have a high prevalence of HCV. Multi-transfused patients still exposed to the risk of transmission of HCV. IL28B gene polymorphismsare not associated with spontaneous clearance of HCV in this cohort of Egyptian children with SCD.

Differentially regulated gene expression associated with hepatitis C virus clearance

Human chronic hepatitis C virus (HCV) infections pose a significant public health threat, necessitating the development of novel treatments and vaccines. HCV infections range from spontaneous resolution to end-stage liver disease. Approximately 10-30% of HCV infections undergo spontaneous resolution independent of treatment by yet-to-be-defined mechanisms. These individuals test positive for anti-HCV antibodies in the absence of detectable viral serum RNA. To identify genes associated with HCV clearance, this study compared gene expression profiles between current drug users chronically infected with HCV and drug users who cleared their HCV infection. This analysis identified 91 differentially regulated (up- or downregulated by twofold or more) genes potentially associated with HCV clearance. The majority of genes identified were associated with immune function, with the remaining genes categorized either as cancer related or 'other'. Identification of factors and pathways that may influence virus clearance will be essential to the development of novel treatment strategies.