Histopathology of hepatitis C in children, a systematic review: implications for treatment

ESPGHAN recommendations on treatment of chronic hepatitis C virus infection in adolescents and children including those living in resource-limited settings

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease worldwide, with more than three million viraemic adolescents and children. Treatment of adults with HCV infection and HCV-related liver disease has advanced considerably thanks to development and improvements in therapy. Direct-acting antiviral regimens are safe and effective. Three regimens with pangenotypic activity (glecaprevir/pibrentasvir, sofosbuvir/velpatasvir and sofosbuvir/velpatasvir/voxilaprevir) and three regimens with genotype-specific activity (sofosbuvir/ribavirin, sofosbuvir/ledipasvir and elbasvir/grazoprevir) have been approved with age-specific limitation for treatment of children with chronic hepatitis C by the European Medicines Agency and the United States Food and Drug Administration. The World Health Organization has set the ambitious target to eliminate hepatitis C as a major public health threat by 2030 and based its actions against HCV on the large use of direct acting antivirals. These updated European Society for Pediatric Gastroenterology, Hepatology and Nutrition recommendations on treatment of hepatitis C describe the optimal therapeutic management of adolescents and children with HCV infection including specific indications for those living in resource-limited settings.

Efficacy and safety of treatment with sofosbuvir/velpatasvir in patients aged 6-18 years with chronic hepatitis C-Results of the PANDAA-PED study

BACKGROUND AND AIMS

The aim of this non-commercial, open-label, real-life, non-randomized clinical trial was to analyse the efficacy and safety of a pangenotypic regimen sofosbuvir/velpatasvir (SOF/VEL) in patients aged 6-18 years with chronic hepatitis C virus (HCV) infection.

METHODS

Fifty patients qualified for the 12-week treatment were divided into two weight groups: 15 children weighting between 17 and <30 kg received a fixed dose of 200/50 mg of SOF/VEL (tablet) once daily, and 35 patients weighting ≥30 kg were treated with 400/100 mg SOF/VEL. The primary endpoint of the study was efficacy defined as sustained viral response (undetectable HCV RNA using an real-time polymerase chain reaction method) at 12 weeks posttreatment (SVR12).

RESULTS

Median age of the participants was 10 (IQR 8-12) years, 47 were infected vertically, and 3 patients were previously ineffectively treated with pegylated interferon and ribavirin. Thirty-seven participants were infected with HCV genotype 1, 10 with HCV genotype 3 and the remaining 3 with genotype 4. There was no case of cirrhosis. SVR12 was 100%. Thirty-three reported adverse events (AEs) were considered related to the administration of SOF/VEL, all of them were mild or moderate. Children presenting with AEs were older compared to these without AEs: 12 (9.5-13) versus 9 (IQR 8-11) years (p = 0.008).

CONCLUSIONS

Results of the PANDAA-PED study indicated a 100% effectiveness of a 12-week therapy with SOF/VEL in children aged 6-18 years with chronic HCV infection and its good safety profile, in particular in younger patients.

Epidemiology and Natural History of Childhood-Acquired Chronic Hepatitis C: A Single-Center Long-Term Prospective Study

OBJECTIVES

To prospectively describe the epidemiology and long-term outcome of childhood-acquired hepatitis C virus (HCV) infection in a large cohort of children followed at a single center.

METHODS

All children with chronic HCV infection followed at the Liver Unit of our tertiary Hospital in Florence (Italy) from January 1, 1988, to September 30, 2021, were included in the analysis.

RESULTS

The final sample consisted of 163 children (median age at enrollment 4 years, interquartile range (IQR): 10; median age at last follow-up 14 years, IQR: 7). The median duration of follow-up was 86 months (IQR: 112). One hundred twenty-five children were vertically infected and 26 acquired the infection horizontally. Twenty-six of the 125 children who were vertically infected (20.8%) underwent spontaneous clearance of HCV RNA at a median age of 4 years (IQR: 2), whereas all the others remained persistently viremic. One patient was diagnosed with cirrhosis; 2 presented clinically detectable extrahepatic manifestations (chronic urticaria). Thirty-two children (19.6%) received antiviral therapy: 8 out of 32 (25%) were treated with pegylated-interferon alfa-2b [sustained virological response (SVR) 24 weeks after the end of treatment in 7/8]; 24 out of 32 (75%) were treated with direct-acting antivirals (SVR 12 weeks after the end of treatment in 23/24).

CONCLUSIONS

The present study describes the largest cohort of children with chronic HCV infection prospectively evaluated with a long follow-up at a single center. HCV infection in children is often a chronic infection that can be cured with modern antiviral therapy. Early treatment could prevent the development of advanced liver disease.

Clinical practice guidelines for the management of children with mother-to-child transmitted hepatitis C virus infection

BACKGROUND

The first guidelines for care of pregnant women carrying the hepatitis C virus (HCV) and their infants were published in 2005 in Japan. Since then, evidence has gradually accumulated worldwide regarding the natural course and treatment of this condition and, especially in recent years, treatment for chronic hepatitis C in adult patients has made great progress. However, the clinical practice policy for children has not been standardized, and new clinical practice guidelines for children with mother-to-child (MTC) transmitted HCV infection have become necessary.

METHODS

In the development of the current guideline, we requested cooperation from The Japanese Society for Pediatric Infectious Diseases, The Japan Society of Hepatology, and the Japan Society of Obstetrics and Gynecology. The committee members were recommended and approved by each society to participate in developing the guidelines. The guideline was also created in accordance with the Minds Guide for Practice Guideline Development. The statements were prepared by consensus-building using the Delphi method, based on the comprehensively searched academic papers and guidelines. These articles were retrieved through searching the PubMed, Cochrane Library, and the Igaku Chuo Zasshi databases.

RESULTS

Eight clinical questions (CQs) with clinical statements were developed regarding etiology (CQs 1-3), diagnosis (CQs 4 and 5), and treatment (two CQs 6 and 7). In each statement, the consensus rate, evidence level, and recommendation level were determined.

CONCLUSION

The guidelines will be helpful in the management of children with hepatitis C MTC transmission.

Safety and Efficacy of Ledipasvir/Sofosbuvir in the Treatment of Chronic Hepatitis C Virus Infection in Treatment-Naïve Children without and with Comorbidities

BACKGROUND

Chronic hepatitis C virus (HCV) infection represents a crucial health problem in children that greatly influences their quality of life. Many efforts have been directed toward investing in effective drugs with a high safety profile and oral administration for better compliance.

OBJECTIVES

This study aims to assess the safety of a fixed-dose combination of ledipasvir/sofosbuvir plus drug efficacy and sustained virologic response (SVR) at 12 weeks after treatment discontinuation.

METHOD

One tablet (90 mg ledipasvir, 400 mg sofosbuvir) was administered to treatment-naïve children aged 12-18 years weighing at least 35 kg with chronic HCV infection for 6 months, genotype 4. Patients were divided into 2 groups, (1) without comorbidities (24 patients) and (2) with comorbidities (26 patients).

RESULTS

At the end of the therapy, all patients (100%) had SVR and a significant reduction of liver enzymes with mild tolerable side effects.

CONCLUSION

Ledipasvir/sofosbuvir fixed-dose combination is a safe and highly effective therapeutic option in Egyptian children aged ≥ 12 years, with chronic HCV infection, genotype 4, either without or with comorbidities.

Effective and Safe Daclatasvir Drug Exposures Predicted in Children Using Adult Formulations

BACKGROUND

Sofosbuvir (SOF)/daclatasvir (DCV) is the direct-acting antiviral regimen of choice in many low- and middle-income countries for curative treatment of chronic hepatitis C virus (HCV) infection in adults, but data on the use of DCV in children are lacking. We performed a population pharmacokinetic (PK) analysis to predict DCV exposure in children treated with available adult formulations.

METHODS

DCV concentration data from HCV-infected adolescents receiving SOF/DCV [400/60 mg, once daily (OD)] who participated in a PK study in Egypt were used for model development. PK parameters were estimated using a population approach. Monte Carlo simulations were run for virtual children weighing 10 to <35 kg receiving 60 or 30 mg OD, and DCV exposures were compared with adults ranges.

RESULTS

Seventeen HCV-infected adolescents (13 males) provided 151 DCV concentrations. Median (range) age was 14 (11-18) years and weight 50 (32-63) kg. In these adolescents receiving 60 mg DCV, median (interquartile range) DCV area under the concentration time curve 0 to 24 hours, maximum concentrations, and minimum concentrations were 11,130 (8140-14,690) ng·h/mL, 1030 (790-1220) ng/mL and 130 (110-220) ng/mL, respectively, compared with 10,343 (7661-14,095) ng·h/mL, 1132 (876-1518) ng/mL and 110 (55.7-192) ng/mL predicted in children 10 to <35 kg receiving 30 mg. The proportion of children with DCV exposures above the adult range rapidly increased for children <30 kg using 60 mg OD, similarly for children 10-14 kg using 30 mg.

CONCLUSIONS

DCV 30 mg OD was predicted to achieve effective and safe exposures in children 14 to <35 kg, perhaps down to 10 kg. These results should be validated clinically. Low-cost available adult DCV formulations together with approved pediatric doses of SOF would expand global access to HCV treatment for children.

Breakthroughs and challenges in the management of pediatric viral hepatitis

Chronic infections by hepatitis B virus (HBV) and hepatitis C virus (HCV) major causes of advanced liver disease and mortality worldwide. Although regarded as benign infections in children, their persistence through adulthood is undoubtedly of concern. Recent advances in HCV treatment have restored the visibility of these conditions and raised expectations for HBV treatment, which is currently far from being curative. Herein we describe direct-acting antivirals available for pediatric HCV (sofosbuvir/ledipasvir, sofosbuvir/velpatasvir, glecaprevir/pibrentasvir) and their real-world use. A critical review of the HBV pediatric classification is provided. Anti-HBV investigational compounds are reviewed in light of the pathophysiology in the pediatric population, including capsid assembly modulators, antigen secretion inhibitors, silencing RNAs, and immune modifiers. Recommendations for screening and management of immunosuppressed children or those with other risk factors or comorbidities are also summarized.

Management of Hepatitis C in Children and Adolescents

The management of hepatitis C virus (HCV) infections has changed dramatically in recent years with the use of direct antiviral agents (AADs). New AADs have excellent safety profile and demonstrated to be highly effective. Interferon free regimens are now recommended for children and adolescents but significant barriers for treatment exist. Overcoming those barriers will facilitate HCV elimination. This review covers varied topics to familiarize providers with the current status of pediatric HCV management in light of newly available DAAs medications.

Systematic review with meta-analysis: the efficacy and safety of direct-acting antivirals in children and adolescents with chronic hepatitis C virus infection

BACKGROUND

The effect of direct-acting anti-virals (DAAs) in children and adolescents with chronic hepatitis C virus (HCV) infection is difficult to determine, since few, aged between 3 and 18 years, have been enrolled in clinical trials, and some data come from observational studies.

AIM

To summarise the evidence on efficacy and safety of DAAs in children and adolescents with chronic HCV infection.

METHODS

We performed a systematic review and meta-analysis of prospective studies on the efficacy and safety of DAAs in subjects <18 years of age. We considered the sustained virological response at post-treatment week 12 as efficacy outcome and adverse events as safety outcome. We considered intervention effect for each study arm by calculating the proportion of sustained virologic response at post-treatment week 12 in subjects receiving all doses of treatment and proportion of adverse events in subjects receiving at least one dose of treatment. Pooled proportions were calculated using the Freeman-Tukey double arcsine transformation. Random effects model was used for all analyses.

RESULTS

Among 39 included studies (1796 subjects), the pooled proportion among those receiving all doses of treatment and reaching sustained virologic response at post-treatment week 12 was 100% (95% confidence interval: 100-100). Considering subjects receiving at least one dose of treatment, lowest estimates were reported among children with cirrhosis (83%). Headache and fatigue were the most common adverse events. Serious adverse events were uncommon.

CONCLUSIONS

Children and adolescents with chronic HCV infection can be safely treated with DAAs with similar efficacy as reported in adults.

Management of hepatitis C in children and adolescents during COVID-19 pandemic

In recent years, significant progress in the antiviral treatment of chronic hepatitis C (CHC) has been made due to the development of interferon-free therapies. Three different highly effective, oral direct-acting antiviral (DAA) regimens have been approved for use in adolescents with CHC between the ages of 12-years-old and 17-years-old in Europe. According to the current recommendations, all treatment-naïve and treatment-experienced children with CHC virus infection should be considered for DAA therapy to prevent the possible progression of hepatitis C virus-related liver disease and its complications. However, the novel coronavirus disease 2019 outbreak, which was classified as a pandemic in March 2020, is currently spreading throughout the world, resulting in a disruption of the healthcare system. This disruption is having a negative impact on the care of patients with chronic diseases, including children with CHC. Thus, several efforts have to be made by pediatric hepatologists to prioritize patient care in children with CHC. These efforts include promoting telemedicine in the outpatient setting, using local laboratory testing for follow-up visits, and engaging in the home delivery of DAAs for patients under antiviral therapy whenever possible.

Hepatitis C Virus Treatment in Children: A Challenge for Hepatitis C Virus Elimination

Hepatitis C is a global public health threat. The introduction of direct-acting antivirals (DAAs) brings the prospect of curing the 71 million people living with the disease, dramatically changing the landscape of hepatitis C. The World Health Organization developed a roadmap for the elimination and cure of hepatitis C by 2030 with a clear goal with measurable targets. However, there is a lack of a well-defined strategy to tackle the hepatitis C virus (HCV) problem in children and adolescents vis-à-vis the adult population. Hepatitis C in children and adolescents can be addressed as part of a national policy for elimination in the whole population, namely macroelimination, or could be fragmented into a microelimination approach targeting the high-risk population groups. Children born to HCV-infected mothers, adolescents who are injecting drugs, migrants, and those suffering from inherited blood diseases are important target populations. After the U.S. Food and Drug Administration approval for the use of DAAs in children aged 3 years and above, evidence from clinical trials and real-world experience was accumulated using brand and generic medicines, with sustained virological response rates exceeding 95%. The evidence created should guide policies on the management of hepatitis C in children and adolescents. There are many challenges in managing HCV in this left-behind marginalized population. The lack of awareness and epidemiological data, consent age, prohibitive prices of medicines, and absence of policies on access to diagnostics, treatment, and linkage to care are among the many barriers to service delivery that should be addressed to achieve the elimination goal by 2030.

Paediatric hepatitis C virus infection and its treatment: Present, past, and future

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease in the world. It is a challenging medico-social problem in the paediatric population. High HCV infection rates are reported in low and middle incomes countries. From the health economic point of view treatment of hepatitis C virus (HCV) with subsequent virus eradication is very effective as it eliminates the long-term sequelae of untreated or maltreated HCV. In this review we summarize the updates and highlight the historical approach of treatment of chronic HCV infection in children in the new era of directly acting antiviral (DAA) agents.

Treatment and monitoring of children with chronic hepatitis C in the Pre-DAA era: A European survey of 38 paediatric specialists

The burden of paediatric Hepatitis C virus (HCV) infection across Europe is unknown, as are current policies regarding monitoring and treatment. This collaborative study aimed to collect aggregate data to characterise the population of ≤18-year-olds with HCV infection in specialist follow up in a 12-month period (2016) across the PENTAHep European consortium, and investigate current policies around monitoring and treatment. A cross-sectional, web-based survey was distributed in April 2017 to 50 paediatricians in 19 European countries, covering patients' profile, and monitoring and treatment practices. Responses were received from 38/50 clinicians collectively caring for 663 children with chronic HCV infection of whom three-quarters were aged ≥6 years and 90% vertically infected. HCV genotype 1 was the most common (n 380; 57.3%), followed by genotype 3, 4 and 2. Seventeen children (3%) with chronic HCV infection were diagnosed with cirrhosis, and six were reported to have received liver transplantation for HCV-related liver disease. The majority (n 425; 64.1%) of the European children with HCV infection remained treatment-naive in 2016. Age affected clinicians' attitudes towards treatment; 94% reported being willing to use direct-acting antivirals, if available, in adolescents (aged ≥11 years), 78% in children aged 6-10 and 42% in those 3-5 years of age (Pearson correlation coefficient -0.98; P 0.0001). This survey provides the largest characterisation of the population of children in clinical follow-up for chronic HCV infection in Europe, alongside important contextual information on their management and treatment. Discussion is needed around strategies and criteria for use of direct-acting antivirals in these children.

Hepatitis C virus infection in children and adolescents

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease and associated morbidity and mortality worldwide. Short-course, oral, curative, direct-acting antiviral regimens have transformed treatment for HCV infection. Since the 2016 launch of the first global strategy towards elimination of viral hepatitis as a public health threat by 2030, the predominant focus of the global response has been on the treatment of adults, who bear the greatest burden of morbidity and mortality of HCV-related chronic liver disease. Compared with adults, there has been little attention paid to addressing the response to HCV in children and adolescents, in part because of the scarcity of data to inform specific paediatric management practices and policy. In this Series paper, we summarise knowledge on the epidemiology, natural history, and treatment of chronic HCV infection in adolescents and children, and we highlight key differences from infection acquired in adulthood. The estimated global prevalence and burden of HCV infection in children aged 1-19 years is 0·15%, corresponding to 3·5 million people (95% CI 3·1-3·9 million). HCV infection is usually asymptomatic during childhood, and cirrhosis and hepatocellular carcinoma are rare. Sofosbuvir with ledipasvir and sofosbuvir with ribavirin have received regulatory approval and guidelines recommend their use in adolescents aged 12 years and older with HCV infection. In April, 2019, glecaprevir with pibrentasvir also received regulatory approval for adolescents aged 12-17 years. Key actions to address the current policy gaps and achieve treatment scale-up that is comparable to that in adults include: establishment of a campaign on access to testing and treatment that is targeted at children and adolescents; fast-track evaluation of pan-genotypic regimens; and accelerated approval of paediatric formulations. Research gaps that need to be addressed include: age-specific prevalence studies of HCV viraemia in priority countries; further validation of non-invasive tests for staging of liver disease in children; and establishment of paediatric treatment registries and international consortia to promote collaborative research agendas.

Treatment of Adolescents With Chronic Hepatitis C Virus Infection: New Regimen on the Block

BLURB FOR ETOC

Editorial to Leung et al. "Ombitasvir/Paritaprevir/Ritonavir With or Without Dasabuvir and With or Without Ribavirin for Adolescents With HCV Genotype 1 or 4".

Peripheral lymphocytes analyses in children with chronic hepatitis C virus infection

BACKGROUND

Hepatitis C virus (HCV)-specific immune response is believed to play a crucial role in viral clearance. There is, nevertheless, no reliable parameter to monitor this immune response or predict chronic HCV infection development.

METHOD

An observational case-control study was performed to identify such parameters, peripheral blood mononuclear cells from 57 children with chronic HCV were systemically phenotyped, and the serum level of Interferon gamma and interleukin (IL) -17 was measured. The data were compared with 37 age-matched healthy volunteers (controls).

RESULTS

Children with chronic HCV infection had a lower frequency of natural killer cells (NK) cells, CD56Dim NK cells and expansion of CD56Bright NK cells compared with controls (P = 0.001, P < 0.0001 and P < 0.0001 respectively). Increased CD56Dim NK cells were negatively correlated with the higher viral load, R²  = 0.29, P = 0.05, while, increased NK T cells were positively correlated with high viral load, R²  = 0.17, P = 0.011. T helper cells, naive T cells, CD127 negative T cells, and HLA-DR-positive T cells significantly increased in patients than in controls. The frequency of CD4+CD25high+ T regulatory (Treg) cells increased in HCV-infected patients, compared with those in control, and FOXP3 was upregulated within them. Treg cells' increase was positively correlated with high viral load, R²  = 0.45, P = 0.004. The level of IL-17 was higher in HCV patients than that in control, P < 0.0001.

CONCLUSION

Although the contribution of those markers to the chronic HCV establishment in children remains elusive, the results may provide important clues for reliable indicators of HCV infection.

Hepatitis C virus infection in children: How do we prevent it and how do we treat it?

INTRODUCTION

Hepatitis C virus (HCV) infection is an important contributor to the worldwide burden of liver-related morbidity and mortality. Mother-to-child transmission of HCV ranges from 6 to 11% in different populations globally, but accurate estimates on the burden of pediatric HCV infection are limited because screening approaches are not consistent. Areas covered: The advent of new direct-acting antiviral agents that achieve very high rates of sustained virologic response (representing virologic cure) with short (i.e. 8-12 weeks) regimens has revolutionized the field of HCV treatment and led to the development of global elimination goals for HCV transmission and mortality. However, information on their safety during pregnancy and efficacy in preventing mother-to-child transmission is lacking. Currently, there are no approved treatment regimens with these antiviral agents for children younger than 12 years of age. Expert commentary: If these agents are shown to be safe during pregnancy and effective in preventing transmission to the infant, screening of pregnant women and antenatal treatment of those infected, could pave the way for eliminating pediatric HCV infection- particularly as these drugs become less costly and more accessible. Treatment of infected children when indicated, along with universal safe health care practices, can further pediatric HCV elimination.

Hepatitis C virus infection in children in the era of direct-acting antiviral

Hepatitis C virus (HCV) infection remains an important global health problem with chronic infection affecting approximately 11 million children worldwide. The emergence of direct-acting antiviral (DAA) therapies and the development of non-invasive methods for the determination of liver fibrosis will significantly improve the management of paediatric patients with chronic HCV infection in subsequent years. For paediatric patients, a new era of highly effective DAA agents is beginning, and the first results of available clinical trials are very promising. In this era, the identification and monitoring of patients continues to be an important issue. The availability of non-invasive serological and imaging methods to measure hepatic fibrosis enables the identification of patients with significant or advanced liver fibrosis stages. This article summarizes the current data on the epidemiology and progress of research aimed to evaluate the new therapies and non-invasive methods for liver injury in paediatric patients with chronic hepatitis C.

Treatment of Chronic Hepatitis C Virus Infection in Children: A Position Paper by the Hepatology Committee of European Society of Paediatric Gastroenterology, Hepatology and Nutrition

OBJECTIVES

In 2017, the European Medicines Agency and the Food and Drug Administration approved the use of the fixed-dose combination of ledipasvir/sofosbuvir and of the combination of sofosbuvir and ribavirin for treatment of adolescents (12-17 years or weighing >35 kg) with chronic hepatitis C virus (HCV) genotype 1, 4, 5, and 6 and genotype 2 and 3 infections, respectively. Although trials with direct-acting antivirals are ongoing for younger children, the only available treatment in the United States and Europe for those <12 years is still the dual therapy of pegylated interferon and ribavirin. There is currently a lack of a systematic approach to the care of these patients. The Hepatology Committee of the European Society of Pediatric Gastroenterology, Hepatology and Nutrition developed an evidence-based position paper for the management of chronic HCV infection in children.

METHODS

A systematic literature search and meta-analysis were performed using MEDLINE and Embase from June 1, 2007 to June 1, 2017. The approach of the Grading of Recommendations Assessment, Development and Evaluation was applied to evaluate outcomes. European Society of Pediatric Gastroenterology, Hepatology and Nutrition Committee members voted on each recommendation, using the nominal voting technique.

RESULTS

The efficacy of the different direct-acting antivirals combinations tested was higher, the relapse and the treatment discontinuation rates lower when compared to pegylated interferon and ribavirin.

CONCLUSIONS

This position paper addresses therapeutic management issues including goals, endpoints, indications, contraindications, and the optimal treatment regimen in children with chronic HCV infection.

[Hepatitis C during pregnancy, vertical transmission and new treatment possibilities]

Hepatitis C virus (HCV) infection has been recognised as a worldwide health problem. HCV is the most common cause of cirrhosis, hepatocellular carcinoma and liver transplantation. The HCV prevalence reported in pregnant women is similar to that found among the general population and does not appear to have an adverse effect on the course of pregnancy. The vertical transmission of HCV (HCV-VT) is a major route of HCV infection in children in the developed countries (>90%). The overall rate of mother-to-child transmission and chronification is about 3%-8%; however, this rate is higher for mothers who are co-infected with the human immunodeficiency virus (15-20%). In this review, we analyse the course of HCV infection during gestation, the risk factors associated with HCV-VT, the diagnostic methods/clinical monitoring recommended and the new possibilities of treatment in the era of direct-acting antiviral agents, which are essential to guide future public health efforts appropriately.

Altered natural killer cells subsets distribution in children with hepatitis C following vertical transmission

BACKGROUND

Natural killer (NK) cells number, phenotypes and function have been evaluated in many studies in adults with hepatitis C as compared with healthy controls or dynamically during interferon-based and interferon-free treatments. Overall, in adults with chronic infection number of circulating NK cells has been reported to be lower when compared to spontaneous resolvers and healthy subjects. Different studies yielded inconsistent findings due to patient and virus heterogeneity.

AIM

To evaluate NK cells in children according to the different outcomes of the infection.

METHODS

In this cross-sectional study, we examined numbers and phenotypes of circulating NK cells from a homogenous cohort of Italian children with vertically acquired hepatitis C.

RESULTS

We compared 31 children who developed chronic infection with nine who presented spontaneous clearance and 13 controls. CD56(+) CD3(-) NK cell numbers were consistently lower in the persistently infected group (P = 0.03 and 0.04). This decrease was due to depletions of CD56(dim) NK cells (P = 0.03 chronic infection vs. spontaneous clearance), while CD56(bright) NK cells were expanded (P = 0.03). No significant difference was found in the frequencies of CD56(+) CD16(+) and CD56(dim) CD16(-) cells. Perforin expression was higher in children with chronic infection (P = 0.03 vs. spontaneous clearance).

CONCLUSIONS

Altered NK cells number and phenotypes could impact the outcome of HCV infection in children following vertical transmission. This study suggests for the first time that NK cells cytolytic function, featured by CD56(dim) cells, contributes to the elimination of HCV in children presenting spontaneous clearance.