Intermediate Monocytes in Acute Alcoholic Hepatitis Are Functionally Activated and Induce IL-17 Expression in CD4+ T Cells.

In humans, the three main circulating monocyte subsets are defined by their relative cell surface expression of CD14 and CD16. They are all challenging to study because their characteristics are strongly context specific, and this has led to a range of conflicting reports about their function, which is especially so for CD14++CD16+ (intermediate) monocytes. Ex vivo cultures are also often confounded by the concomitant use of immunosuppressive drugs. We therefore sought to characterize the phenotype and function of intermediate monocytes in the setting of acute inflammation prior to treatment in a cohort of 41 patients with acute alcoholic hepatitis (AH). Circulating intermediate monocytes were enriched in patients with AH and had an activated phenotype with enhanced expression of CCR2 and CD206 compared with healthy controls. Proinflammatory cytokine expression, including IL-1ß and IL-23, was also higher than in healthy controls, but both classical (CD14++CD16-) and intermediate monocytes in AH were refractory to TLR stimulation. Compared with healthy controls, both AH monocyte subsets had greater phagocytic capacity, enhanced ability to drive memory T cell proliferation in coculture, and skewed CD4+ T cells to express an increased ratio of IL-17/IFN-γ. Furthermore, liver tissue from AH patients demonstrated an enrichment of monocytes including the intermediate subset compared with controls. These data demonstrate that intermediate monocytes are expanded, functionally activated, induce CD4+ T cell IL-17 expression, and are enriched in the liver of patients with AH.

A polymorphism in IL28B distinguishes exposed, uninfected individuals from spontaneous resolvers of HCV infection.

BACKGROUND & AIMS: Polymorphisms in the interleukin-28B (IL28B) gene are associated with outcomes from infection with hepatitis C virus (HCV). However, the role of these polymorphisms in protecting injection drug users who are at high risk for HCV infection but do not have detectable antibodies against HCV or HCV RNA (exposed uninfected) has not been demonstrated. We investigated whether these individuals have the IL28B genotype rs12979860-CC, which protects some individuals against HCV infection. METHODS: Seventy-four exposed uninfected individuals, 89 spontaneous resolvers, and 234 chronically infected individuals were genotyped to determine single nucleotide polymorphisms at IL28B.rs12979860. RESULTS: Exposed, uninfected individuals had a significantly lower frequency of the protective genotype (rs12979860-CC) than anti-HCV-positive spontaneous resolvers (41.9% vs 69.7%, respectively; P=.0005; odds ratio [OR], 0.31; 95% confidence interval [CI]: 0.16-0.60) but a similar frequency to patients who were chronically infected (41.9% vs 43.6%, respectively; P=ns). However, exposed, uninfected individuals had a significantly higher frequency of homozygosity for killer cell immunoglobulin-like receptor 2DL3:group 1 HLA-C (KIR2DL3:HLA-C1) than those with chronic infection (31.1% vs 13.3%, respectively; P=.0008; OR, 2.95; 95% CI: 1.59-5.49). For patients who spontaneously resolved infection, IL28B and KIR:HLA protected, independently, against chronic HCV infection, based on logistic regression and synergy analyses (synergy factor, 1.3; 95% CI: 0.37-4.75; P synergy=.6). CONCLUSIONS: IL28B and KIR2DL3:HLA-C1 are independently associated with spontaneous resolution of viremia following HCV exposure. Resistance to HCV infection in exposed uninfected cases is associated with homozygosity for KIR2DL3:HLA-C1 but not the single nucleotide polymorphism IL28B.rs12979860. Uninfected individuals are therefore a distinct population from patients who spontaneously resolve HCV infection. Distinct, nonsynergistic innate immune mechanisms can determine outcomes of HCV exposure.

Loss of virus-specific T-cell responses in HCV exposed uninfected injection drug users with drug rehabilitation.

INTRODUCTION: Hepatitis C virus (HCV)-specific T lymphocyte responses have been demonstrated in peripheral blood from injection drug users (IDUs) persistently HCV antibody and RNA negative despite high-risk behavior. We have termed these apparently HCV resistant cases "Exposed Uninfecteds" (EUs), and have studied the evolution of T-cell responses to determine if they are protective in nature. METHODS: Twenty-one EU cases were studied using a questionnaire to ascertain injecting behavior details. Peripheral blood mononuclear cells were isolated from whole blood and an interferon-gamma (IFN-γ) enzyme-linked immunosorbent spot (ELISPOT) assay used to detect T-cell responses to a panel of HCV proteins. EU cases were subdivided by injecting drug patterns into (1) cases in rehabilitation who stopped injecting, (2) prisoners (infrequent/noninjectors), and (3) cases who continued to inject. RESULTS: EUs continuing to inject had significantly stronger (P < .01) and more frequent (P < .05) HCV-specific IFN-γ ELISPOT responses than controls or noninjecting EUs. EUs in rehabilitation lost their T-cell responses during follow-up, while those continuing to inject maintained them. CONCLUSIONS: HCV-specific T-cell responses in EU cases wane within months of cessation of injection drug use. Maintenance of these T-cell responses appears to be dependent on continuing HCV exposure through injection drug use.

Consistent beneficial effects of killer cell immunoglobulin-like receptor 2DL3 and group 1 human leukocyte antigen-C following exposure to hepatitis C virus.

UNLABELLED: Natural killer cells are a key component in the immune control of viral infections. Their functions are controlled by inhibitory receptors for major histocompatability complex (MHC) class I, including the killer cell immunoglobulin-like receptors (KIR). KIR2DL3 in combination with its cognate human leukocyte antigen (HLA)-C ligand has been shown to be associated with spontaneous resolution of viremia following hepatitis C virus (HCV) infection. In order to determine if this gene combination is advantageous across all potential outcomes following HCV exposure, we studied individuals with apparent resistance to HCV infection who remain seronegative and aviremic despite long-term injection drug use and also individuals chronically infected with HCV who successfully clear HCV with treatment. Homozygosity for KIR2DL3 in combination with group 1 HLA-C allotypes was more frequent in exposed seronegative aviremic individuals as compared to those with chronic HCV (25.0% versus 9.7%, P = 0.003, odds ratio [OR] = 3.1, 95% confidence interval [CI] = 1.3-7.1) in a model similar to that found for those spontaneously resolving HCV. In individuals undergoing treatment for HCV, those with KIR2DL3 and group 1 HLA-C were more likely to make a sustained virological response (SVR) (P = 0.013, OR = 2.3, 95% CI = 1.1-4.5). KIR and HLA-C protection in both treatment response and spontaneously resolving HCV was validated at the allelic level, in which KIR2DL3-HLA-Cw*03 was associated with SVR (P = 0.004, OR = 3.4, 95% CI = 1.5-8.7) and KIR2DL3/KIR2DL3-HLA-Cw*03 was associated with spontaneous resolution of HCV infection (P = 0.01, OR = 2.3, 95% CI = 1.2-4.4). CONCLUSION: KIR and HLA-C genes are consistently beneficial determinants in the outcome of HCV infection. This advantage extends to the allelic level for both gene families.

Altered coronal tissue of the human dental pulp in chronic hepatitis C virus infected patients.

INTRODUCTION: Hepatitis C virus (HCV) infection is characterized by a high rate of chronicity and concerns 170 million individuals worldwide. Extrahepatic manifestations are frequently observed in patients with chronic viral hepatitis. Although extrahepatic manifestations do exist with all hepatitis viruses, they are more commonly associated with chronic HCV infection. This study aimed to evaluate qualitatively and quantitatively the effect of chronic HCV infection on the coronal tissue of the human dental pulp. METHODS: Thirty sound impacted teeth were obtained from healthy individuals as healthy controls. The patient group included another 30 sound impacted teeth obtained from chronic HCV-infected patients. The coronal pulp tissues were carefully removed, fixed, and processed to be stained with hematoxylin-eosin, alcian blue (2.5)/periodic acid-Schiff, van Gieson, and fibronectin. RESULTS: The tissue sections of chronic HCV patients revealed disorganized pulp tissue, chronic inflammatory cell infiltrate, thickening, stenosis and occlusion of large-sized blood vessel arteriole, and collapsed venule and lymphatic system. The acidic, neutral, and mixed mucins were increased, whereas the amount of collagen was decreased, accompanied with marked decrease in the distribution and quantity of fibronectin glycoprotein. Application of Kruskal-Wallis test showed that there were statistically significant changes between the 2 groups (P ≤ .05). CONCLUSIONS: The coronal tissue of the dental pulp, like any other body tissues, is affected by chronic HCV infection, with an inappropriate cellularity, vasculature, and extracellular matrix proteins. The clinician should be alerted to these histologic changes and their subsequent implications.

Vasculitis of dental pulp associated with cryoglobulinemia in hepatitis C virus patients: case report.

INTRODUCTION: This report presents a case of impacted lower third molar extracted for surgical reasons in patient with uncontrolled hepatitis C. After decalcification, dental pulp vasculature and its tissue quality were investigated. METHODS: Serial sections of 4-µm thickness along the midline buccolingually for the demineralized specimen were obtained, mounted on a glass slide, stained with hematoxylin-eosin, covered, and viewed under the light microscope. RESULTS: The histologic investigation of the pulp tissue revealed thickening, stenosis, and occlusion of the vessel wall, ectopic calcification of the pulp tissue in close association with pulpal blood vessels, interrupted and vacuolated odontoblastic layer in the coronal pulp chamber, with an inflammatory cell infiltrate throughout the pulpal tissue. CONCLUSIONS: Cryoglobulinemia associated with uncontrolled hepatitis C virus infection in patients endangers the dental pulp vasculature and alters its normal tissue architecture.

Hepatitis C virus (HCV)--specific T cell responses in injection drug users with apparent resistance to HCV infection.

BACKGROUND: Injection drug users (IDUs) are at risk of acquiring hepatitis C virus (HCV) infection. We have identified a cohort of long-term IDUs who remain uninfected by HCV despite high-risk behavior. We have categorized these subjects as "exposed uninfected" and have sought immunological correlates with this apparent resistance. METHODS: We studied 40 exposed uninfected subjects testing negative for both HCV antibody and HCV RNA. Details of injection behavior were ascertained by questionnaire. In vitro interferon (IFN)-gamma production by T cells in response to HCV proteins (core, E1, NS3, NS4, and NS5) was quantified by enzyme-linked immunospot assay, and findings were compared with those in 21 healthy control subjects. RESULTS: All exposed uninfected subjects reported sharing needles or other injection paraphernalia on multiple occasions. The mean duration of injecting was 9.3 years (range, 0.5-26 years), with a median estimated number of injection episodes of 8760. IFN-gamma production in response to HCV proteins was found in 23 (58%) of 40 exposed uninfected subjects versus 4 (19%) of 21 control subjects (P = .004), with 14 exposed uninfected subjects responding to multiple antigens, compared with none of the control subjects (P = .001). CONCLUSIONS: The majority of long-term IDUs who remain uninfected by HCV despite their high-risk behavior have HCV-specific T cell responses. These responses were frequently found for multiple HCV proteins, making cross-reactivity to other homologous antigens unlikely. These responses may represent an immunological footprint of HCV exposure that has not resulted in viremia or HCV antibody seroconversion. The potential role played by these responses in protection from HCV infection is of clinical importance.

Variant Creutzfeldt-Jakob disease: prion protein genotype analysis of positive appendix tissue samples from a retrospective prevalence study.

OBJECTIVE: To perform prion protein gene (PRNP) codon 129 analysis in DNA extracted from appendix tissue samples that had tested positive for disease associated prion protein. DESIGN: Reanalysis of positive cases identified in a retrospective anonymised unlinked prevalence study of variant Creutzfeldt-Jakob disease (vCJD) in the United Kingdom. STUDY SAMPLES: Three positive appendix tissue samples out of 12,674 samples of appendix and tonsil tested for disease associated prion protein. The patients from whom these samples were obtained were aged 20-29 years at the time of surgery, which took place in 1996-9. SETTING: Pathology departments in two tertiary centres in England and Scotland. RESULTS: Adequate DNA was available for analysis in two of the three specimens, both of which were homozygous for valine at codon 129 in the PRNP. CONCLUSIONS: This is the first indication that the valine homozygous subgroup at codon 129 in the PRNP is susceptible to vCJD infection. All tested clinical cases of vCJD have so far occurred in the methionine homozygous subgroup, and a single case of probable iatrogenic vCJD infection has been identified in one patient who was a methionine/valine heterozygote at this genetic locus. People infected with vCJD with a valine homozygous codon 129 PRNP genotype may have a prolonged incubation period, during which horizontal spread of the infection could occur either from blood donations or from contaminated surgical instruments used on these individuals during the asymptomatic phase of the illness.

Prevalence of lymphoreticular prion protein accumulation in UK tissue samples.

This study aims to provide an estimate of the number of individuals in the UK who may be incubating variant Creutzfeldt-Jakob disease and at risk of causing iatrogenic spread of the disease. Lymphoreticular accumulation of prion protein is a consistent feature of variant Creutzfeldt-Jakob at autopsy and has also been demonstrated in the pre-clinical phase. Immunohistochemical accumulation of prion protein in the lymphoreticular system remains the only technique that has been shown to predict neurological disease reliably in animal prion disorders. In this study, immunohistochemistry was used to demonstrate the presence of prion protein, with monoclonal antibodies KG9 and 3F4, in surgically removed tonsillectomy and appendicectomy specimens. The samples were collected from histopathology departments across the UK and anonymised prior to testing. Samples were tested from 16 703 patients (14 964 appendectomies, 1739 tonsillectomies), approximately 60% of whom were from the age group 20-29 years at operation. Twenty-five per cent of the samples were excluded from the final analyses because they contained inadequate amounts of lymphoid tissue. Three appendicectomy samples showed lymphoreticular accumulation of prion protein, giving an estimated prevalence of 3/12 674 or 237 per million (95% CI 49-692 per million). The pattern of lymphoreticular accumulation in two of these samples was dissimilar from that seen in known cases of variant Creutzfeldt-Jakob disease. Although it is uncertain whether immunohistochemical accumulation of prion protein in the lymphoreticular system is specific for variant Creutzfeldt-Jakob disease, it has not been described in any other disease, including other forms of human prion disease or a range of inflammatory and infective conditions. These findings reinforce the importance of measures taken by the UK Department of Health to reduce the risk of spread of variant Creutzfeldt-Jakob via blood products and surgical instruments, and of the urgency to proceed with large-scale screening of fresh tonsil specimens for the presence of prion protein.