Prospective follow-up of patients with acute hepatitis C virus infection in Brazil

A potential new way to facilitate HCV elimination: The prediction of viremia in anti-HCV seropositive patients using machine learning algorithms

BACKGROUND AND STUDY AIMS

The present study was undertaken to design a new machine learning (ML) model that can predict the presence of viremia in hepatitis C virus (HCV) antibody (anti-HCV) seropositive cases.

PATIENTS AND METHODS

This retrospective study was conducted between January 2012-January 2022 with 812 patients who were referred for anti-HCV positivity and were examined for HCV ribonucleic acid (HCV RNA). Models were constructed with 11 features with a predictor (presence and absence of viremia) to predict HCV viremia. To build an optimal model, this current study also examined and compared the three classifier data mining approaches: RF, SVM and XGBoost.

RESULTS

The highest performance was achieved with XGBoost (90%), which was followed by RF (89%), SVM Linear (85%) and SVM Radial (83%) algorithms, respectively. The four most important key features contributing to the models were: alanine aminotransferase (ALT), aspartate aminotransferase (AST), albumin (ALB) and anti-HCV levels, respectively, while "ALB" was replaced by the "AGE" only in the XGBoost model.

CONCLUSION

This study has shown that XGBoost and RF based ML models, incorporating anti-HCV levels and routine laboratory tests (ALT, AST, ALB), and age are capable of providing HCV viremia diagnosis with 90% and 89% accuracy, respectively. These findings highlight the potential of ML models in the early diagnosis of HCV viremia, which may be helpful in optimizing HCV elimination programs.

Negative impact of HIV infection on broad-spectrum anti-HCV neutralizing antibody titers in HCV-infected patients with advanced HCV-related cirrhosis

OBJECTIVES

The current study aimed to assess the impact of HIV on the production of anti-HCV antibodies in HCV-infected individuals with advanced HCV-related cirrhosis before and 36 weeks after the sustained virological response (SVR) induced by direct-acting antivirals (DAAs) therapy.

METHODS

Prospective study on 62 patients (50 HIV/HCV-coinfected and 12 HCV-monoinfected). Plasma anti-E2 and HCV-nAbs were determined respectively by ELISA and microneutralization assays.

RESULTS

At baseline, the HCV-group had higher anti-E2 levels against Gt1a (p = 0.012), Gt1b (p = 0.023), and Gt4a (p = 0.005) than the HIV/HCV-group. After SVR, anti-E2 titers against Gt1a (p < 0.001), Gt1b (p = 0.001), and Gt4a (p = 0.042) were also higher in the HCV-group than HIV/HCV-group. At 36 weeks post-SVR, plasma anti-E2 titers decreased between 1.3 and 1.9-fold in the HIV/HCV-group (p < 0.001) and between 1.5 and 1.8-fold in the HCV-group (p ≤ 0.001). At baseline, the HCV-group had higher titers of HCV-nAbs against Gt1a (p = 0.022), Gt1b (p = 0.002), Gt2a (p < 0.001), and Gt4a (p < 0.001) than the HIV/HCV-group. After SVR, HCV-nAbs titers against Gt1a (p = 0.014), Gt1b (p < 0.001), Gt2a (p = 0.002), and Gt4a (p = 0.004) were also higher in the HCV-group. At 36 weeks post-SVR, HCV-nAbs decreased between 2.6 and 4.1-fold in the HIV/HCV-group (p < 0.001) and between 1.9 and 4.0-fold in the HCV-group (p ≤ 0.001).

CONCLUSIONS

HIV/HCV-coinfected patients produced lower levels of broad-spectrum anti-HCV antibodies than HCV-monoinfected patients.

Antibody Responses in Hepatitis C Infection

Antibody responses in hepatitis C virus (HCV) have been a rather mysterious research topic for many investigators working in the field. Chronic HCV infection is often associated with dysregulation of immune functions particularly in B cells, leading to abnormal lymphoproliferation or the production of autoantibodies that exacerbate inflammation and extrahepatic diseases. When considering the antiviral function of antibody, it was difficult to endorse its role in HCV protection, whereas T-cell response has been shown unequivocally critical for natural recovery. Recent breakthroughs in the study of HCV and antigen-specific antibody responses provide important insights into viral vulnerability to antibodies and the immunogenetic and structural properties of the neutralizing antibodies. The new knowledge reinvigorates HCV vaccine research by illuminating a new path for the rational design of vaccine antigens to elicit broadly neutralizing antibodies for protection.

High spontaneous clearance of symptomatic iatrogenic acute hepatitis C genotype 4 infection

Acute hepatitis C (AHC) infection resolves spontaneously in 15% to 40% of patients. Factors favoring spontaneous viral clearance remain undefined. In this study, predictors of spontaneous viral clearance in patients with symptomatic AHC were investigated. Epidemiological, clinical, and virologic parameters were also examined. Patients with symptomatic AHC were enrolled and followed up prospectively. The patients were followed up every 2 weeks in the first month and then monthly for the following 5 months, with a follow-up visit 6 months after the last hepatitis C virus (HCV)-RNA negative sample for those who had cleared the virus. Interleukin (IL)-28B.rs12979860 single-nucleotide polymorphism and HCV genotype were tested at baseline. HCV-RNA was tested during each visit. Patients who remained RNA-positive at 24 weeks were treated with pegylated interferon plus ribavirin for 24 weeks. A total of 30 patients, mostly with iatrogenically acquired AHC genotype 4 infections completed 6-months' follow-up, to either spontaneous clearance or start of treatment. The mean age of the patients was 37 ± 13 years. In total, 67% of patients were females, and the mean incubation period was 7.6 ± 3.5 weeks. Viral clearance occurred spontaneously in 19 (63.3%) patients. The average time to clearance was 24.3 ± 9.6 weeks. A total of 11 patients received therapy, and 8 (72.7%) cleared the virus and had a sustained virologic response to the treatment 24 weeks after the therapy. A total of three patients were treatment nonresponders. IL28B.rs12979860 CC genotype, female gender, and viremia level were not associated with self-limiting AHC in this cohort. In conclusion, patients with symptomatic AHC genotype 4 infection caused by an iatrogenic exposure had higher rates of spontaneous resolution than previously reported. Predicting spontaneous viral clearance after iatrogenic AHC exposure was not possible in this population.

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.

Clinical epidemiology of acute hepatitis C in South America

There is scarce data pertaining to acute hepatitis C (aHC) infection in South America. We aimed to describe clinical characteristics and evolution of aHC in a South American cohort. A retrospective survey was conducted at 13 hepatology units. All patients ≥16 years old with aHC diagnosis were included. Demographic, clinical and outcome information were registered in a standardized ad hoc questionnaire. Sixty-four patients were included. The majority were middle-aged (median age: 46 years) and female (65.6%); most of them were symptomatic at diagnosis (79.6%). HCV-1 was the most prevalent genotype (69.2%). Five patients had liver failure: three cases of severe acute hepatitis, one case of fulminant hepatitis and one case of acute-on-chronic liver failure. Nosocomial exposure was the most prevalent risk factor. Evolution was assessed in 46 patients. In the untreated cohort, spontaneous resolution occurred in 45.8% and was associated with higher values of AST/ALT and with the absence of intermittent HCV RNA viremia (P = 0.01, 0.05, and 0.01, respectively). In the treated cohort, sustained virological response was associated with nosocomial transmission and early treatment initiation (P = 0.04 each). The prevalence of nosocomial transmission in this South-American cohort of aHC stresses the importance of following universal precautions to prevent HCV infection. J. Med. Virol. 89:276-283, 2017. © 2016 Wiley Periodicals, Inc.

The natural history of recent hepatitis C virus infection among blood donors and injection drug users in the country of Georgia

Introduction

Hepatitis C virus (HCV) infection is a serious health problem in Georgia.

Methods

We conducted a prospective study to identify and characterize the natural history of recent HCV infection since very first days of infection. Recent HCV infection was defined as detectable plasma HCV RNA in the absence of anti-HCV antibodies.

Results

A total of 7600 HCV seronegative blood donors and 3600 HCV seronegative drug users were screened for recent HCV infection. Among them 7 (0.09 %) blood donors and 10 (0.28 %) drug users tested positive for HCV RNA and were classified as having recent HCV infection. Of these 17 patients 4 (23.5 %) spontaneously cleared the virus by the end of 24 week follow-up. Five clinical forms of recent HCV infection were identified during the follow-up. Four patients had symptomatic disease, including 3 patients with jaundice and other clinical symptoms (2 of them cleared virus) and 1 patient only had other symptoms without jaundice. All symptomatic patients had ALT elevation. Three distinct variants of asymptomatic disease were identified in 13 patients: 9 patients had ALT elevation and none cleared the virus; 2 patients developed chronic disease without ALT elevation; 2 patients cleared virus without anti-HCV seroconversion and without ALT elevation; this form can be described as transitory HCV viremia.

Conclusion

Additional studies are needed to define clinical and public health implications of transitory HCV viremia. Our study suggests the need for implementing nucleic acid testing of blood donors and key populations in order to more effectively identify HCV infected persons.

Hepatitis C virus treatment as prevention among injecting drug users: who should we cure first?

BACKGROUND AND AIMS

Treatment of injecting drug users (IDU) for hepatitis C virus (HCV) infection may prevent onward transmission. Treating individuals who often share injecting equipment is most likely to prevent new infections. However, these high-risk IDU are also more likely to become re-infected than low-risk IDU. We investigated to which group treatment is best targeted.

DESIGN

We modelled the expected benefits per treatment of one chronically HCV-infected IDU in a population of low- and high-risk IDU. The benefits of treating one low- or one high-risk IDU were compared.

MEASUREMENTS

Benefits included the probability for the treated IDU to become and remain uninfected, as well as the expected number of prevented infections to others (i.e. we quantified the total expected decrease in chronic infections).

FINDINGS

We found a threshold in HCV-RNA prevalence above which treating low-risk IDU, and below which treating high-risk IDU, resulted in the greatest benefits. This threshold was at 50% of exchanged syringes being HCV contaminated. When 42% of IDU engaged in high-risk behaviour (borrowing and lending out syringes 7.3 times more frequently than low-risk IDU), the corresponding threshold of HCV-RNA prevalence among IDU was at 32%. Larger-risk heterogeneity led to a lower corresponding threshold among IDU. A combination of HCV treatment and 50% risk reduction was best directed at high-risk IDU for prevalence among syringes up to 59%. The threshold was marginally sensitive to changes in disease and treatment variables.

CONCLUSIONS

When more than half of all exchanged syringes in a population of injecting drug users (IDU) are contaminated by hepatitis C virus, it is most efficient to treat low-risk IDU first. Below this threshold, it is most efficient to treat high-risk IDU first.

Predictors of spontaneous viral clearance and outcomes of acute hepatitis C infection

Background/Aims

This study evaluated the predictors of spontaneous viral clearance (SVC), as defined by two consecutive undetectable hepatitis C virus (HCV) RNA tests performed ≥12 weeks apart, and the outcomes of acute hepatitis C (AHC) demonstrating SVC or treatment-induced viral clearance.

Methods

Thirty-two patients with AHC were followed for 12-16 weeks without administering antiviral therapy.

Results

HCV RNA was undetectable at least once in 14 of the 32 patients. SVC occurred in 12 patients (37.5%), among whom relapse occurred in 4. SVC was exhibited in 8 of the 11 patients exhibiting undetectable HCV RNA within 12 weeks. HCV RNA reappeared in three patients (including two patients with SVC) exhibiting undetectable HCV RNA after 12 weeks. SVC was more frequent in patients with low viremia than in those with high viremia (55.6% vs. 14.3%; P=0.02), and in patients with HCV genotype non-1b than in those with HCV genotype 1b (57.1% vs. 22.2%; P=0.04). SVC was more common in patients with a ≥2 log reduction of HCV RNA at 4 weeks than in those with a smaller reduction (90% vs. 9.1%, P<0.001). A sustained viral response was achieved in all patients (n=18) receiving antiviral therapy.

Conclusions

Baseline levels of HCV RNA and genotype non-1b were independent predictors for SVC. A ≥2 log reduction of HCV RNA at 4 weeks was a follow-up predictor for SVC. Undetectable HCV RNA occurring after 12 weeks was not sustained. All patients receiving antiviral therapy achieved a sustained viral response. Antiviral therapy should be initiated in patients with detectable HCV RNA at 12 weeks after the diagnosis.

Role of IL28B gene polymorphism and cell-mediated immunity in spontaneous resolution of acute hepatitis C

BACKGROUND

 A single-nucleotide polymorphism (SNP; rs12979860) near the IL28B gene has been associated with spontaneous and treatment-induced hepatitis C virus clearance. We investigated predictors of spontaneous disease resolution in a cohort of patients with acute hepatitis C (AHC), analyzing epidemiological, clinical and virological parameters together with IL28B.rs12979860 genotypes and cell-mediated immunity (CMI).

METHODS

 Fifty-six symptomatic AHC patients were enrolled and followed prospectively. CMI was measured in 31 patients at multiple time points by interferon-γ enzyme-linked immunospot assay and was correlated to the IL28B.rs12979860 SNP.

RESULTS

 Eighteen patients had a self-limiting AHC that was associated with female sex (P = .028), older age (P = .018), alanine aminotransferase level >1000 U/L (P = .027), total bilirubin level >7 mg/dL (P = .036), and IL28B.rs12979860 genotype CC (P = .030). In multivariate analysis, only CC genotype was independently associated with self-limiting AHC (odds ratio, 5.3; 95% confidence interval, 1.1-26.5). Patients with the CC genotype with self-limiting AHC had a stronger (P = .02) and broader (P = .013) CMI than patients with the CT genotype with chronically evolving AHC. In patients with chronically evolving disease, CC genotype was associated with a broader CMI compared to CT genotype (P = .028). A negative CMI was more frequently associated with CT genotype among persistently infected patients (P = .043) and with persistent infection among CT patients (P = .033).

CONCLUSIONS

. Self-limiting AHC was independently associated with CC genotype. The correlation between IL28B.rs12979860 genotypes and CMI is suggestive of a possible important role of CMI in favoring hepatitis C virus clearance in CC patients.

Case definitions for acute hepatitis C virus infection: a systematic review

BACKGROUND & AIMS

Case definitions for recent hepatitis C virus (HCV) infection vary considerably between studies. The aim of this systematic review was to characterize case definitions for recent HCV and explore the heterogeneity in studies performed to date.

METHODS

A systematic literature search of MEDLINE, SCOPUS, and ISI Web of Knowledge was performed covering all studies of recent HCV infection cited between January 2000 and June 2011. The criteria used by each study to define cases of recent HCV infection were extracted, structured, and analyzed.

RESULTS

Overall, 195 articles were included, with 87% (n=169) providing a clear case definition for recent HCV infection. The most frequently used individual criteria for defining a case included HCV antibody seroconversion (77%), alanine aminotransferase (ALT) elevation (68%), and HCV RNA detection (63%). In studies using HCV antibody seroconversion, the window period between the last negative and the first positive antibody test varied widely across studies (4 weeks to 4 years). Considerable diversity was also observed with respect to the ALT threshold used to characterize ALT elevations, ranging from 2 to 20 times the upper limit of normal. HCV antibody seroconversion was used as a single criterion in 41% of the studies, while all other studies used at least two criteria (range: 2-9). Epidemiology/surveillance studies mostly used a more sensitive case definition, whereas treatment studies, natural history studies, and diagnosis studies used more specific case definitions.

CONCLUSIONS

Marked heterogeneity in case definitions for recent HCV infection was observed. Although a single case definition for recent HCV is not warranted, a degree of standardization within specific study categories would enable improved cross-study comparison and more uniform evaluation of HCV prevention and management strategies.

Laboratory diagnostics for hepatitis C virus infection

Identification of prevalent infection by hepatitis C virus (HCV) is based serologically on detecting anti-HCV immunoglobulin G, using immunoassays, immunoblot assays, and, more recently, immunochromatography-based rapid tests. None discriminate between active and resolved HCV infection. Tests for detecting HCV RNA identify active HCV infection but are costly. Serologic assays for HCV antigens have been developed and show potential for diagnosis of active HCV infection, and their performance characteristics are undergoing evaluation. The diagnosis of acute HCV infection without the demonstration of seroconversion remains elusive.

Association of IL-10, IL-4, and IL-28B gene polymorphisms with spontaneous clearance of hepatitis C virus in a population from Rio de Janeiro

BACKGROUND

Cytokines play an important role in the regulation of the immune response. In hepatitis C virus (HCV) infection, cytokine levels may influence the outcome of acute HCV infection. Polymorphisms in cytokine genes have been associated to different expression levels in response to infection. This study was carried out to investigate the association of several cytokine gene polymorphisms with disease outcome in HCV-infected patients.

FINDINGS

Patients with chronic or spontaneously resolved HCV infection were included in a cross-sectional study. A comparative analysis was performed between the groups regarding frequency distribution of the following cytokines' gene polymorphisms: IL-10 (-1082 A/G; -819 T/C; -592 A/C), IL-4 (+33C/T), IFN-γ (+874 T/A), TNF-α (-238 G/A and -308 G/A) and IL-28B (rs12979860 C/T and rs8099917 T/G).

RESULTS

Eighteen patients with spontaneous viral clearance and 161 with chronic HCV infection were included. In the comparative analysis, the GG genotype of the IL-10 polymorphism -1082A/G was more frequent in patients with spontaneous viral clearance when compared to patients with chronic HCV (41.2% vs 6.2%; p = 0.001). This association was also found for the CC genotype of the IL-4 polymorphism +33C/T (72.2% vs 36.7%; p = 0.017) and the CC and TT genotypes of the IL-28B polymorphisms rs 12979860 and rs 8099917 (88.9% vs 30.3%; p < 0.001 and 88.9% vs 49.6%; p = 0.002). The IL10 (A-1082 G) and IL-28B (Crs12979860T) gene polymorphisms showed odds ratios of 12.848 and 11.077, respectively, and thus may have a greater influence on HCV spontaneous viral clearance. The IFN-γ (+874 T/A), TNF-α (-238 G/A and -308 G/A) polymorphisms did not show significant association with spontaneous viral clearance or chronicity.

CONCLUSION

The G allele for IL-10 (-1082 A/G), the C allele for IL-4 (+3 C/T) and the C and T alleles for IL-28B (rs12979860 and rs8099917, respectively) are associated with spontaneous viral clearance in hepatitis C infection.

Immediate vs. delayed treatment in patients with acute hepatitis C based on IL28B polymorphism: a model-based analysis

BACKGROUND & AIMS

Timing of treatment initiation in acute hepatitis C (AHC) patients is unclear. Spontaneous viral clearance argues for a "watch-and-wait" strategy. However, early initiation of treatment could increase the sustained virological response (SVR) rate. We compared three different HCV treatment initiation strategies in patients with AHC according to presence of clinical symptoms and IL28B polymorphism: (1) within 2 months after transmission (immediate initiation), (2) at 3 months (early initiation), and (3) at 4/5 months (delayed initiation).

METHODS

We calculated spontaneous HCV clearance probability based on the symptomatic (sAHC) and asymptomatic (aAHC) nature of disease and C/C or non-C/C genotype. We used different SVR probabilities according to delay between transmission and treatment. We estimated the probability of developing chronic hepatitis C (CHC).

RESULTS

The probability of developing CHC was lower for immediate treatment initiation (7.1% in C/C and 7.3% in non-C/C patients with sAHC; 6.6% in C/C and 7.1% in non-C/C patients with aAHC) than for delayed initiation (13.5% in C/C and 18.0% in non-C/C patients with sAHC; 14.6% in C/C and 18.5% in non-C/C patients with aAHC) regardless of the presence of symptoms or IL28B genotype.

CONCLUSIONS

In patients such as health care workers, in whom HCV is detected ≤ 2 months following transmission, treatment should be immediately initiated regardless of clinical symptoms and IL28B polymorphism. In those in whom HCV is detected>2 months after transmission, treatment 4/5 months after may be preferable because of a higher rate of spontaneous HCV clearance after 2 months and a poor HCV treatment efficacy's differential between months 3 and 4/5.

Spontaneous clearance of primary acute hepatitis C virus infection correlated with high initial viral RNA level and rapid HVR1 evolution

The aim of this study is to determine whether early viral dynamics and evolution predict outcome of primary acute hepatitis C virus (HCV) infection. HCV- and human immunodeficiency virus-negative injection drug users were enrolled prospectively and followed monthly to identify acute HCV infection using RNA detection. Subjects with more than 1 month between HCV-RNA-negative and -positive visits were excluded to ensure stringent acute infection. Differences in medians of log-transformed viral RNA levels and evolutionary rates in each gene of a 5'-hemigenomic amplicon were assessed using Mann-Whitney's rank-sum test. Correlation coefficient was calculated using Spearman's rank order. Initial viremia level was 50-fold higher in subjects with spontaneous clearance (compared with persistence) of primary acute HCV infection (median, 7.1 versus 5.4 log(10) IU/mL; P = 0.002). Initial viremia level in subjects with interleukin (IL)28B-C allele at rs12979860 and clearance was higher than that in subjects with IL28B-T allele and persistence (P = 0.001). Evolutionary rates in the hypervariable region 1 (HVR1) region of the E2 gene were significantly higher in self-resolvers than those in persistence subjects during early infection, whereas other genes or regions had comparable rates. All major substitutions in HVR1 in persistence subjects were convergent changes, whereas over the same time interval clearance subjects displayed divergent evolution, indicating different immune responses between the two groups.

CONCLUSION

Spontaneous clearance of acute HCV infection is predicted by high initial viremia as well as favorable IL28B genotype and is associated with rapid envelope-sequence evolution. This linkage of host genetics, viral dynamics, and evolution provides new directions for mechanistic studies. (HEPATOLOGY 2012;55:1684-1691).

An intermediate dose of LCMV clone 13 causes prolonged morbidity that is maintained by CD4+ T cells

Wasting is a sign of various underlying disorders and is a common feature of cancer, sepsis, and AIDS. We have developed an in vivo model to study the various stages of wasting following infection of mice with lymphocytic choriomeningitis virus cl-13. Using this model we have identified four distinct stages of wasting and have discovered that all stages occur in the different groups of mice regardless of whether the virus is cleared or persists. However, the degree and extent of wasting vary between groups of mice, depending upon the dose of virus administered. Blocking IFNγ or TNFα, which are believed to take part in the wasting process, did not affect the wasting state. Finally, we found that CD4+ T cells control the maintenance stage of wasting. We believe this model will be useful in studying the regulation of wasting during a persistent viral infection, hopefully leading to improved therapies to ameliorate the disorder.

The impact of illicit drug use on spontaneous hepatitis C clearance: experience from a large cohort population study

BACKGROUND AND AIMS

Acute hepatitis C infection usually ends in chronic infection, while in a minority of patients it is spontaneously cleared. The current population-based study is performed on a large cohort in Golestan province of Iran to examine the demographic correlates of Spontaneous Hepatitis C Clearance.

METHODS

Serum samples used in this study had been stored in biorepository of Golestan Cohort Study. These samples were evaluated for anti hepatitis C Virus by third generation Enzyme-linked immunosorbent assay (ELISA). Subjects who tested positive were then invited and tested by Recombinant Immunoblot Assay (RIBA) and Ribonucleic Acid Polymerase Chain Reaction test (PCR). If tested positive for RIBA, subjects were recalled and the two tests were re-done after 6 months. Those subjects who again tested positive for RIBA but negative for PCR were marked as cases of spontaneous clearance.

RESULTS

49,338 serum samples were evaluated. The prevalence of Chronic Hepatitis C Virus (CHCV) infection based on PCR results was 0.31%. Among those who had acquired hepatitis C, the rate of SC was 38%. In multivariate analysis, illicit drug use both Injecting Use (OR = 3.271, 95% CI: 1.784-6.000, p-value<0.001) and Non-Injecting Use (OR = 1.901, 95% CI: 1.068-3.386, p-value = 0.029) were significant correlates of CHCV infection versus SC.

CONCLUSIONS

Illicit drug use whether intravenous or non-intravenous is the only significant correlate of CHCV, for which several underlying mechanisms can be postulated including repeated contacts with hepatitis C antigen.

Antibody dynamics and spontaneous viral clearance in patients with acute hepatitis C infection in Rio de Janeiro, Brazil

Background

The anti-HCV antibody response has not been well characterized during the early phase of HCV infection and little is known about its relationship to the clinical course during this period.

Methods

We analyzed serial anti-HCV antibodies longitudinally obtained from a prospective cohort of 65 patients with acute HCV infection by using a microparticle enzyme immunoassay AxSYM HCV 3.0 (Abbott Diagnostics) during the first 12 months from HCV acquisition in Rio de Janeiro, Brazil. Spontaneous viral clearance (SVC) was defined as undetectable HCV RNA in serum, in the absence of treatment, for three consecutive HCV PCR tests within 12-months of follow-up.

Results

Baseline antibody values were similar among patient groups with self-limiting HCV evolution (n = 34) and persistent viremia (n = 31) [median (interquartile range) signal/cut-off ratio (s/co) 78.7 (60.7-93.8) vs. 93.9 (67.8-111.9), p = 0.26]. During 12-months follow-up, patients with acute spontaneous resolving HCV infection showed significantly lower serial antibody response in comparison to individuals progressing to chronic infection [median (interquartile range) s/co 62.7 (35.2-85.0) vs. 98.4 (70.4-127.4), p < 0.0001]. In addition, patients with self-limiting HCV evolution exhibited an expeditious, sharp decline of serial antibody values after SVC in comparison to those measured before SVC [median (interquartile range) s/co 56.0 (25.4-79.3) vs. 79.4 (66.3-103.0), p < 0.0001].

Conclusion

Our findings indicate a rapid short-term decline of antibody values in patients with acute spontaneous resolving HCV infection.