Extrahepatic manifestations of hepatitis C infection

Hepatitis C virus association with peripheral blood B lymphocytes potentiates viral infection of liver-derived hepatoma cells

Hepatitis C virus (HCV) primarily replicates within the liver, leading to hepatitis, fibrosis, and hepatocellular carcinoma. Infection is also associated with B-cell abnormalities, suggesting an association of the virus with B cells. The infectious JFH-1 strain of HCV can bind primary and immortalized B cells but fails to establish productive infection. However, B cell-associated virus readily infects hepatoma cells, showing an enhanced infectivity compared with extracellular virus. B cells express the viral receptors CD81, SR-BI, and the C-type lectins DC-SIGN and L-SIGN. Antibodies specific for SR-BI and DC-SIGN/L-SIGN reduced B-cell transinfection, supporting a role for these molecules in B-cell association with HCV. Stimulation of B cells with CD40 ligand and interleukin-4 promoted their ability to transinfect hepatoma cells. B cell-associated virus is resistant to trypsin proteolysis and HCV-specific neutralizing antibodies, consistent with particle internalization. HCV promoted the adhesion of primary B cells to Huh-7 hepatomas, providing a mechanism for B-cell retention in the infected liver. In summary, B cells may provide a vehicle for HCV to persist and transmit to the liver.

Hepatitis C virus infection and primary Sjögren's syndrome: a clinical and serologic description of 9 patients

OBJECTIVE

To define the clinical and immunologic profile of 9 patients with Sjögren's Syndrome (SS) and Hepatitis C virus (HCV) infection.

PATIENTS

9 out of 305 patients with SS, diagnosed according to the criteria proposed in 2002, had repeated positive serology for HCV.

RESULTS

9 female patients were studied. The mean age at onset of SS was 59 years, with a mean period of follow-up of 7.1 years. All the patients had glandular manifestations and they were all positive for dacryologic tests. Salivary gland biopsy was performed in 4 patients, all showing characteristic lymphocytic infiltrate. The main extraglandular features were arthralgias, photosensitivity, purpura, thyroiditis. All the patients were positive for anti-nuclear antibodies (ANA): 6 anti-Ro/SSA, 3 anti-Ro/SSA and anti-La/SSB positive. HCV-positive SS were compared with 296 patients with primary SS. They showed higher mean age (p=0.01), higher prevalence of photosensitivity (p=0.0266) and circulating cryoglobulins (p=0.0372). In primary SS, most patients had anti-Ro/SSA antibodies alone (49.8%) or associated to anti-La/SSB (46.5%). Five patients (1.8%) had other ANA specificities.

CONCLUSIONS

A chronic HCV infection is concomitant in about 3% of patients with pSS. They differ from patients without HCV infection for the higher prevalence of photosensitivity and cryoglobulins, without clinical manifestations of cryoglobulinemia.

Hepatitis C virus (HCV)-induced immunoglobulin hypermutation reduces the affinity and neutralizing activities of antibodies against HCV envelope protein

Hepatitis C virus (HCV) often causes persistent infection despite the presence of neutralizing antibodies against the virus in the sera of hepatitis C patients. HCV infects both hepatocytes and B cells through the binding of its envelope glycoprotein E2 to CD81, the putative viral receptor. Previously, we have shown that E2-CD81 interaction induces hypermutation of heavy-chain immunoglobulin (V(H)) in B cells. We hypothesize that if HCV infects antibody-producing B cells, the resultant hypermutation of V(H) may lower the affinity and specificity of the HCV-specific antibodies, enabling HCV to escape from immune surveillance. To test this hypothesis, we infected human hybridoma clones producing either neutralizing or non-neutralizing anti-E2 or anti-E1 antibodies with a lymphotropic HCV (SB strain). All of the hybridoma clones, except for a neutralizing antibody-producing hybridoma, could be infected with HCV and support virus replication for at least 8 weeks after infection. The V(H) sequences in the infected hybridomas had a significantly higher mutation frequency than those in the uninfected hybridomas, with mutations concentrating in complementarity-determining region 3. These mutations lowered the antibody affinity against the targeting protein and also lowered the virus-neutralizing activity of anti-E2 antibodies. Furthermore, antibody-mediated complement-dependent cytotoxicity with the antibodies secreted from the HCV-infected hybridomas was impaired. These results suggest that HCV infection could cause some anti-HCV-antibody-producing hybridoma B cells to make less-protective antibodies.

HLA-DPbeta chain may confer the susceptibility to hepatitis C virus-associated hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a heart muscle disease characterized by hypertrophy and diastolic dysfunction of cardiac ventricles. It is suggested that one possible aetiology of HCM is the hepatitis C virus (HCV) infection, but molecular mechanisms underlying development of HCV-associated HCM (HCV-HCM) remains unknown. Because the human leucocyte antigen (HLA) molecule is involved in the control of progression/suppression of viral infection, extensive HLA allelic diversity may modulate the post-infectious course of HCV and pathogenesis of HCV-HCM. Here we undertook a case-control study with 38 patients with HCV-HCM and 132 unrelated healthy controls to reveal the potential impact of polymorphisms in seven classical and two non-classical HLA genes on the pathogenesis of HCV-HCM. It was found that DPB1*0401 and DPB1*0901 were significantly associated with increased risk to HCV-HCM in dominant model (P < 0.028, OR = 3.94, 95% confidence interval (CI) = 1.19, 13.02) and in recessive model (P < 0.007, OR = 9.85, 95% CI = 1.83, 53.04), respectively. The disparity in the gene-dose effect by two susceptible DPB1 alleles may be attributable to the difference between the susceptible (36 A and 55 A) and resistant (8L, 9F, 11G, 57E and 76M) residue-combination consisting of DPbeta anchor pocket for antigenic peptide-binding. These results implied that the HLA-DP molecules with specificity pocket appropriate for HCV antigen(s) might confer the progressive process of HCM among the HCV-infected individuals.

Increased all-cause, liver, and cardiac mortality among hepatitis C virus-seropositive blood donors

Hospital-based studies suggest that hepatitis C virus (HCV) infection causes frequent cirrhosis, hepatocellular carcinoma, and mortality, but epidemiologic studies have shown less morbidity and mortality. The authors performed a retrospective cohort study of 10,259 recombinant immunoblot assay-confirmed, HCV antibody-positive (HCV+), allogeneic blood donors from 1991 to 2002 and 10,259 HCV antibody-negative (HCV-) donors matched for year of donation, age, gender, and Zone Improvement Plan Code (ZIP Code). Vital status through 2003 was obtained from the US National Death Index, and hazard ratios with 95% confidence intervals were calculated by survival analysis. After a mean follow-up of 7.7 years, there were 601 (2.92%) deaths: 453 HCV+ and 148 HCV- (hazard ratio (HR) = 3.13, 95% confidence interval (CI): 2.60, 3.76). Excess mortality in the HCV+ group was greatest in liver-related (HR = 45.99, 95% CI: 11.32, 186.74), drug- or alcohol-related (HR = 10.81, 95% CI: 4.68, 24.96), and trauma/suicide (HR = 2.99, 95% CI: 2.05, 4.36) causes. There was also an unexpected increase in cardiovascular mortality among the HCV+ donors (HR = 2.21, 95% CI: 1.41, 3.46). HCV infection is associated with a significant, threefold increase in overall mortality among former blood donors, including significantly increased mortality from liver and cardiovascular causes. High rates of mortality from drug/alcohol and trauma/suicide causes are likely due to lifestyle factors and may be at least partially preventable.

Clonal expansion of immunoglobulin M+CD27+ B cells in HCV-associated mixed cryoglobulinemia

Hepatitis C virus (HCV) is associated with B-cell lymphoproliferative disorders such as mixed cryoglobulinemia (MC) and B-cell non-Hodgkin lymphoma (B-NHL). The pathogenesis of these disorders remains unclear, and it has been proposed that HCV drives the pro-liferation of B cells. Here we demonstrate that certain HCV(+)MC(+) subjects have clonal expansions of immunoglobulin M (IgM)(+)kappa(+)IgD(low/-)CD21(low)CD27(+) B cells. Using RT-PCR to amplify Ig from these singly sorted cells, we show that these predominantly rheumatoid factor-encoding V(H)1-69/J(H)4 and V(kappa)3-20 gene segment-restricted cells have low to moderate levels of somatic hypermutations. Ig sequence analysis suggests that antigen selection drives the generation of mutated clones. These findings lend further support to the notion that specific antigenic stimulation leads to B-cell proliferation in HCV MC and that chronic B-cell stimulation may set the stage for malignant transformation and the development of B-NHL. The finding that these hypermutated, marginal zone-like IgM(+)CD27(+) B cells are clonally expanded in certain subjects with MC offers insight into mechanisms of HCV-associated MC and B-cell malignancy. This study was registered at www.clinicaltrials.gov as NCT00219999.

Induction of interleukin-6 by hepatitis C virus core protein in hepatitis C-associated mixed cryoglobulinemia and B-cell non-Hodgkin's lymphoma

PURPOSE

Chronic hepatitis C carries the risk to develop mixed cryoglobulinemia (MC) and B-cell non-Hodgkin's lymphoma (B-NHL), possibly because viral antigens stimulate the host's inflammatory response via extracellular pattern recognition receptors (PRR). To clarify this issue, we studied whether recognition of hepatitis C virus (HCV) proteins by PRR is involved in the pathogenesis of HCV-associated MC or B-NHL.

EXPERIMENTAL DESIGN

Peripheral blood mononuclear cells of patients with HCV-associated B-NHL (n = 12), MC (n = 14), uncomplicated hepatitis C (n = 12), and healthy volunteers (n = 12) were incubated with the recombinant HCV proteins E2, core, and NS3 to study induction of cytokine production, stimulation of B-cell proliferation, and immunoglobulin secretion. In addition, serum levels of interleukin-6 (IL-6) were measured by ELISA.

RESULTS

HCV core was the only studied protein, which induced production of IL-6 and IL-8 in CD14(+) cells. IL-6 induction was mediated via Toll-like receptor 2 (TLR2) and lead to increased B-cell proliferation in vitro. TLR2 expression on monocytes and IL-6 serum concentrations were increased in all groups of HCV-infected patients compared with healthy controls and were highest in MC (P < 0.05).

CONCLUSIONS

Increased secretion of IL-6 via stimulation of TLR2 by HCV core protein may play a role in the pathogenesis of hepatitis C-associated MC and B-NHL.

Simultaneous hepatic relapse of non-Hodgkin's lymphoma and hepatocellular carcinoma in a patient with hepatitis C virus-related cirrhosis

We report a 66-year-old man with hepatitis C virus (HCV)-related cirrhosis and simultaneous hepatic relapse of non-Hodgkin's lymphoma (NHL) and of hepatocellular carcinoma (HCC). Although the liver is frequently involved by NHL, hepatic colocalization of NHL and HCC is rarely detected by imaging techniques. HCV has been suggested to be lymphotrophic as well as hepatotrophic, and therefore has attracted speculation about a causative role in some cases of lymphoma. The patient had a past history of cutaneous diffuse large B cell lymphoma (DLBCL) in concurrence with HCC 32 months previously. Complete remission (CR) had been maintained for both diseases until February 2004, when ultrasonography and computed tomography (CT) showed multiple liver tumors. Two of these, appearing hyperattenuating in the arterial phase of contrast-enhanced CT, were diagnosed histopathologically as HCC, and treated with radiofrequency ablation. The other tumors, hypoattenuating in the portal phase CT, were diagnosed histopathologically as DLBCL, and treated with cyclophosphamide, tetrahydropyranyl-Adriamycin, vincristine and prednisolone (THP-COP) in combination with rituximab. CR was achieved for both DLBCL and HCC. Given the previously demonstrated immune system tropism and perturbation by HCV, the virus might have contributed to the occurrence of the NHL as well as the HCC.

Review article: the pathophysiology of thrombocytopenia in hepatitis C virus infection and chronic liver disease

BACKGROUND

The pathophystology of thrombocytopenia in patients with chronic liver disease resulting from hepatitis C virus (HCV) infection is complex and involves several complementary mechanisms that likely act in concert.

AIM

To summarize the available data on the etiology of thrombocytopenia in patients with chronic liver disease.

RESULTS

In patients with untreated hepatitis C, both prevalence and severity of thrombocytopenia increase in parallel with the extent of disease, usually becoming clinically relevant when patients develop extensive fibrosis and/or cirrhosis. Pathogenetic mechanisms include hypersptenism secondary to portal hypertension, bone marrow suppression resulting from either HCV itself or interferon treatment, aberrations of the immune system resulting in the formation of anti-platelet antibodies and/or immune-complexes that bind to platelets and facilitate their premature clearance, development of immunologically-mediated extrahepatic manifestations including mixed cryoglobulinemia with or without associated joint, renal, or cutaneous involvement, and thrombopoietin (TPO) deficiency secondary to liver dysfunction. In chronic liver disease, the natural inverse relationship between TPO and platelet levels is not maintained; therefore, blood TPO levels fail to have clinical relevance or predictive value in assessing the thrombocytopenic status of a given patient.

CONCLUSIONS

The development of thrombocytopenisa in patients with chronic liver disease is complex and multifactorial.

Introduction: thrombocytopenia in chronic liver disease -- treatment implications and novel approaches

BACKGROUND

Thrombocytopenia is a common hematologic toxicity among patients with chronic liver disease.

AIM

To give a brief overview of thrombocytopenia and its effects on patients with chronic liver disease.

RESULTS

Thrombocytopenia is generally mild to moderate in severity and can thus be managed relatively easily. Severe thrombocytopenia (platelet count <50,000 /microL), however, may present significant challenges to patient management. Thrombocytopenia can increase the risk of bleeding associated with invasive or surgical procedures. Therefore, while perhaps less widely appreciated than the impact of anemia or neutropenia, effective prevention and management of thrombocytopenia is also critical for patients with liver disease.

CONCLUSIONS

This supplement to Alimentary Pharmacology & Therapeutics provides a comprehensive review of the significance of thrombocytopenia in patients with chronic liver disease, its pathophysiology and relationship to coagulation disorders, impact on clinical care and resource utilization, and novel therapies that may be able to supplant platelet transfusions.

Hepatitis C and ocular surface disease

PURPOSE

To assess the frequency of changes in the ocular surface and the presence of hepatitis C virus (HCV) in tear samples of patients with chronic HCV infection.

DESIGN

Prospective, nonrandomized, clinical, interdisciplinary, single-center study.

METHODS

Seventy-one patients with previously untreated chronic HCV infection and a control group consisting of 66 patients without systemic HCV infection were enrolled in the trial. The patients with HCV infection were screened for ocular symptoms, visual acuity, and ocular changes. Tear production was measured by the Jones test. Conjunctival impression cytologic analysis was performed. The presence of HCV ribonucleic acid (RNA) in tear and blood samples was determined by quantitative polymerase chain reaction.

RESULTS

On examination, systemic HCV infection was present for a median of 30 months. Fifty percent of all HCV patients showed a decrease in tear production measured by the Jones test. Apart from epithelial changes related to dry eye syndrome in 12 patients, two patients presented mild peripheral corneal thinning. Polymerase chain reaction analysis detected HCV RNA in five (10%) of 52 tear samples. HCV RNA levels in tear samples (mean, 1.0 x 10(4) copies/ml) were considerably lower than in blood samples (mean, 5.3 x 10(5) copies/ml).

CONCLUSIONS

Dry eye syndrome is the most frequently observed ocular feature in HCV infection. Patients with HCV infection (age range, 21 to 60 years) compared with the controls had a significant lower tear production (P = .05). The presence of HCV RNA in 10% of tear samples emphasizes the potential risk of viral transmission through tears.

An unusual case of autoimmune hemolytic anemia in treatment naïve hepatitis C virus infection

Hepatitis C virus (HCV) infection is emerging as a common and insidiously progressive liver condition. In more than one third of the cases, extrahepatic manifestations are seen in the course of the disease. Over the past decade, authors have reported membranous nephropathy, cutaneous vasculitis, idiopathic thrombocytopenic purpura, porphyria cutanea tarda and diabetes mellitus, among other extrahepatic manifestations of HCV infection. Recently, there have been a growing number of reports relating HCV infection to autoimmune cytopenias. Here, we report an unusual case of Coombs'-negative autoimmune hemolytic anemia (AHA) with severe autoimmune leukopenia and neutropenia, occurring simultaneously, in a patient with untreated hepatitis C infection. Mild cytopenias during chronic hepatitis C have been reported widely in the medical literature; however, severe cytopenias are seldom described and are usually seen only after or simultaneously with therapy.

Hepatitis C virus infection and the prevalence of renal insufficiency

BACKGROUND

Hepatitis C virus (HCV) is associated with pathologic changes in the kidney. However, the association between HCV and renal dysfunction is not well defined.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

This study estimated the prevalence of renal insufficiency among veterans who received care through the Veterans Affairs Puget Sound Health Care System. The study population consisted of veterans who underwent HCV antibody testing between January 1, 1999, and December 31, 2004, and had at least one primary care or medical subspecialty visit and at least one outpatient creatinine measurement within the 18 mo before antibody testing. Veterans were excluded when they had a history of chronic dialysis, creatinine >5 mg/dl, or renal transplantation. Study data were extracted from the electronic medical record. Renal insufficiency was defined as a creatinine level > or =1.5 mg/dl. Multivariate logistic regression was performed to estimate the risk for renal insufficiency associated with HCV. Among 25,782 eligible veterans, 1928 were HCV antibody positive and 23,854 were HCV antibody negative.

RESULTS

Although the proportion with renal insufficiency was lower for antibody-positive versus -negative veterans (4.8 versus 6.0%), after adjustment for age, race, gender, diabetes, and hypertension, HCV-positive veterans had a 40% higher odds for renal insufficiency (odds ratio 1.40; 95% confidence interval 1.11 to 1.76) as compared with HCV-negative veterans.

CONCLUSIONS

HCV was associated with an increased prevalence of renal insufficiency.

Flying Under the Radar: The Immunobiology of Hepatitis C

The hepatitis C virus (HCV) is a remarkably successful pathogen, establishing persistent infection in more than two-thirds of those who contract it. Its success is related to its abilities to blunt innate antiviral pathways and to evade adaptive immune responses. These two themes may be related. We propose that HCV takes advantage of the impaired innate response to delay the organization of an effective adaptive immune attack. The tolerogenic liver environment may provide cover, prolonging this delay. HCV's error-prone replication strategy permits rapid evolution under immune pressure. Persistent high levels of viral antigens may contribute to immune exhaustion. Finally, the virus may benefit from the efficient enlistment of memory T and B cells in the pursuit of a moving target.

Severe hepatitis C virus-related cryoglobulinaemic sensory-motor polyneuropathy treated with pegylated interferon-a2b and ribavirin: clinical, laboratory and neurophysiological study

BACKGROUND/AIMS

Severe involvement of central and/or peripheral nervous system is a rare complication of hepatitis C virus (HCV)-related cryoglobulinaemia.

METHOD

Four patients with HCV-related type II/III cryoglobulinaemia (three males with genotype 1, one female with genotype 3) who presented with severe sensory-motor polyneuropathy, one with central nervous system involvement as well, were treated with pegylated IFNa-2b 1.5 microg/kg/week and ribavirin 10.6 mg/kg/daily for 48 weeks. Neurological evaluation involved detailed clinical motor and sensory scores/scales and neurophysiological studies before and after treatment.

RESULTS/CONCLUSION

Three out of four patients had undetectable serum HCV-RNA, normal levels of aminotransferases and substantially lower or undetectable levels of cryoglobulins at the end of treatment and at 24 weeks follow-up period. Treatment was well tolerated and all patients exhibited significant improvement of neuropathy based on solid clinical and laboratory criteria that was associated with the virological response.

Dermatologic disorders associated with chronic hepatitis C: effect of interferon therapy

Chronic hepatitis C virus infection (HCV) is associated with extrahepatic manifestations, including such dermatologic conditions as mixed cryoglobulinemia, porphyria cutanea tarda, and lichen planus. Patients with chronic HCV and extrahepatic manifestations are often excluded from clinical trials evaluating interferon (IFN) therapy due to concerns about poor response, adverse events, and toxicity. Thus, data regarding the efficacy of IFN not only on the underlying chronic HCV, but also on extrahepatic manifestations, are limited in these patients. Case reports suggest that the response of dermatologic extrahepatic manifestations to IFN in patients with chronic HCV is highly variable. This review summarizes available data on dermatologic conditions associated with chronic HCV and their response to IFN therapy.

Pericardial involvement as an atypical manifestation of giant cell arteritis: report of a clinical case and literature review

PURPOSE

Pericardial effusion has been known to be a rare manifestation of giant cell arteritis. During the last six decades, only 24 cases have been cited in the literature. In this report, we describe the case of a patient presenting with nonspecific symptoms and development of pericardial effusion.

PROCEDURES AND FINDINGS

A 71-year-old woman was admitted to the hospital with low-grade fever, exertion breathlessness, atypical diffuse muscular pain, and weight loss over a period of about 5 weeks. Pericardial effusion and giant cell arteritis were diagnosed by echocardiography and left temporal artery biopsy, respectively. Treatment with corticosteroids resulted in remarkable improvement of symptoms and complete remission of pericardial effusion. One year after admission, the patient remained in a stable good condition, under low steroid maintenance dosage.

CONCLUSIONS

The diversity of clinical manifestations (such as pericardial effusion) in such a potentially severe disease should alert the physician to prompt diagnosis and treatment in view of impending irreparable vascular damages, even in cases in which the initial presentation is quite uncommon.

Sustained virological response correlates with reduction in the incidence of glucose abnormalities in patients with chronic hepatitis C virus infection

OBJECTIVE

There is evidence to suggest that hepatitis C virus (HCV) infection is a high-risk condition for developing type 2 diabetes. However, there are no interventional studies that confirm that HCV infection causes diabetes. The main aim of this study was to compare the incidence of glucose abnormalities (diabetes plus impaired fasting glucose) between HCV-infected patients with or without sustained virological response (SVR) after antiviral therapy.

RESEARCH DESIGN AND METHODS

Patients with normal fasting glucose (<100 mg/dl) with biopsy-proven chronic hepatitis C without cirrhosis and with at least 3 years of follow-up after finishing antiviral therapy were included in the study (n = 234). Patients received interferon alpha-2b (alone or with ribavirin) for 6 or 12 months according to genotype. Cumulative incidence of glucose abnormalities was evaluated by using the Kaplan-Meier method comparing subjects with and without a SVR to antiviral treatment. A multivariate Cox proportional hazards analysis was performed to explore the variables independently associated with the development of glucose abnormalities.

RESULTS

During follow-up, 14 of 96 (14.6%) patients with SVR and 47 of 138 (34.1%) nonsustained responders developed glucose abnormalities (P = 0.001). Patients with SVR did not develop diabetes during follow-up, whereas nine cases of diabetes were detected in nonsustained responders (P = 0.007). After adjustment for the recognized predictors of type 2 diabetes, the hazard ratio for glucose abnormalities in patients with SVR was 0.48 (95% CI [0.24-0.98], P = 0.04).

CONCLUSIONS

Our results provide evidence that eradication of HCV infection significantly reduces the incidence of glucose abnormalities in chronic hepatitis C patients. In addition, this study supports the concept that HCV infection causes type 2 diabetes.

Extrahepatic replication of HCV: insights into clinical manifestations and biological consequences

An estimated 170 million persons are infected with the hepatitis C virus (HCV) worldwide. While hepatocytes are the major site of infection, a broad clinical spectrum of extrahepatic complications and diseases are associated with chronic HCV infection, highlighting the involvement of HCV in a variety of non-hepatic pathogenic processes. There is a growing body of evidence to suggest that HCV can replicate efficiently in extrahepatic tissues and cell types, including peripheral blood mononuclear cells. Nonetheless, laboratory confirmation of HCV replication in extrahepatic sites is fraught with technical challenges, and in vitro systems to investigate extrahepatic replication of HCV are severely limited. Thus, future studies of extrahepatic replication should combine innovative in vitro assays with a prospective cohort design to maximize our understanding of this important phenomenon to the pathogenesis and treatment response rates of HCV.

Extrahepatic manifestations of hepatitis C virus

Given the high prevalence of chronic hepatitis C virus (HCV) infection, its clinical sequelae account for a significant proportion of patients presenting to gastroenterologists and hepatologists. Whereas the hepatic manifestations of hepatitis C are well described, including hepatitis, cirrhosis, and the development of hepatocellular carcinoma, the extrahepatic manifestations, though common, are less well appreciated. Although nonspecific, fatigue and arthralgias are very common in those with chronic hepatitis C. Extrahepatic syndromes have been reported in as much as 36% of HCV patients, but the exact prevalence is not known. Patients with these syndromes can be divided into those with a high degree of association and those with a more moderate or mild association with HCV. The most prevalent extrahepatic diseases with the highest degree of association with HCV are the essential mixed cryoglobulins with skin, neurologic, renal, and rheumatologic complications. Non-cryoglobulin diseases with a less definite relationship to HCV include systemic vasculitis, splenic lymphoma, porphyria cutanea tarda, and the sicca syndromes. This article highlights the pathophysiology and clinical manifestations of these disorders.

Hepatitis C infection and diabetes

Since the discovery of the hepatitis C virus (HCV) in 1989, attention has been paid to the association of chronic HCV infection and the development of diabetes. The risk factors for diabetes include older age, HCV genotype 3, severe liver fibrosis, family history of diabetes, and liver/kidney transplantation. Emerging evidence in animals and humans has shown that HCV infection induces hepatic steatosis and increases tumor necrosis factor-alpha level, both resulting in the development of insulin resistance and subsequent type 2 diabetes. It is suggested that the presence of diabetes and hepatic steatosis may enhance fibrosis progression, hepatocellular carcinoma, and atherosclerosis. Interferon is reportedly associated with improved glucose tolerance. However, interferon might enhance underlying autoimmunity against beta cells, leading to overt type 1 diabetes that is genetically predisposed or give rise to hyperglycemia, resulting in the development of type 2 diabetes. In light of the national epidemic of type 2 diabetes, the link between HCV and diabetes would be a major public health problem. Further clinical researches are awaited in order to effectively detect, prevent, and treat HCV-associated type 2 diabetes, which would also slow the progression of hepatitis C itself.

Interferon-induced sarcoidosis

Interferons (IFNs) are widely used for the treatment of various medical diseases. They have marked immunomodulatory effects, and many reports have been published associating IFN therapy with the induction of autoimmune phenomena and other disorders of immune regulation such as sarcoidosis. The clinical presentation of IFN-induced sarcoidosis (IIS) is insidious and can be confused with common constitutional side effects of these drugs. The age of onset of IIS is later than that of naturally occurring sarcoidosis. The most common organs involved are the lungs and skin. In the majority of cases, IIS follows a benign course. As we show in an illustrative case report, complete resolution after discontinuation of IFN therapy can be expected. This review summarises 65 cases of IIS reported in the literature and highlights the pathophysiology, clinical features, diagnostic modalities and therapeutic options for this increasingly recognised phenomenon.

The haplotype block, NFKBIL1-ATP6V1G2-BAT1-MICB-MICA, within the class III-class I boundary region of the human major histocompatibility complex may control susceptibility to hepatitis C virus-associated dilated cardiomyopathy

Cardiomyopathy is a heart muscle disease with impaired stretch response that can result in severe heart failure and sudden death. A small proportion of hepatitis C virus (HCV)-infected patients may be predisposed to develop dilated cardiomyopathy (DCM) and hypertrophic cardiomyopathy (HCM). The molecular mechanisms involved in the predisposition remain unknown due in part to the lack of information on their genetic background. Because the human leukocyte antigen (HLA) region has a pivotal role in controlling the susceptibility to HCV-induced liver disease, we hypothesized that particular HLA alleles and/or non-HLA gene alleles within the human major histocompatibility complex (MHC) genomic region might control the predisposition to HCV-associated DCM (HCV-DCM) and/or HCV-associated HCM (HCV-HCM). Here, we present mapping results of the MHC-related susceptibility gene locus for HCV-associated cardiomyopathy by analyzing microsatellite and single nucleotide polymorphism markers. To delineate the susceptibility locus, we genotyped 44 polymorphic markers scattered across the entire MHC region in a total of 59 patients (21 HCV-DCM and 38 HCV-HCM) and 120 controls. We mapped HCV-DCM susceptibility to a non-HLA gene locus spanning from NFKBIL1 to MICA gene loci within the MHC class III-class I boundary region. Our results showed that HCV-DCM was more strongly associated with alleles of the non-HLA genes rather than the HLA genes themselves. In addition, no significant association was found between the MHC markers and HCV-HCM. This marked difference in the MHC-related disease susceptibility for HCV- associated cardiomyopathy strongly suggests that the development of HCV- DCM and HCV-HCM is under the control of different pathogenic mechanisms.

Rheumatoid Factors: Good or Bad for You?

BACKGROUND

Rheumatoid factors (RFs) are autoantibodies associated with rheumatoid arthritis. They can be detected in normal individuals, although transiently. This dichotomy has led to questions about the origins and types of RFs. Recently it has been shown that B cells that produce RFs only do so when activated by two signals, one from engagement of the B-cell receptor and the other from recognition of a pathogen-associated molecular pattern through a Toll-like receptor (TLR). These autoantibodies thus link the innate and acquired immune responses.

OBJECTIVE

Through a review of the literature, an examination of the current knowledge of RF induction is presented. The focus is on a discussion of a beneficial or detrimental role for RFs in normal individuals and in those with chronic disease.

RESULTS

What makes RF 'good' in some cases and 'bad' in others may reflect the type of RF produced. Low-affinity polyreactive IgM RFs are probably beneficial as they aid in the clearance of immune complexes that are more efficiently cleared, and the RF B cell can act as an antigen-presenting cell and stimulate host defense. However, large amounts of high-affinity RFs found in patients with chronic disease may be harmful by participation in a vicious cycle of autoantibody production by stimulation of self lymphocytes, and/or deposition in blood vessels thus causing vasculitis.

CONCLUSIONS

Whether RFs are beneficial or detrimental depends on the context in which they are expressed, the type and amount of RF produced, whether the response is perpetuated by TLR ligation and whether other cells are stimulated either directly or indirectly by RF-positive B cells.

Extrahepatic immunological complications of hepatitis C virus infection

Chronic hepatitis C virus (HCV) infection is frequently associated with a number of extrahepatic complications. In the majority of cases the underlying pathogenetic mechanisms are immune mediated, as evidenced by the presence of circulating autoantibodies (mixed cryoglobulinemia), whereas for others a localized host cellular immune response is implicated (e.g. sialadenitis, lichen planus). In this review, the latest data on the pathogenesis and clinical manifestations of the most common autoimmune extrahepatic manifestations of chronic HCV infection are presented.

LKM1 autoantibodies in chronic hepatitis C infection: a case of molecular mimicry?

Anti-liver-kidney microsome type 1 (LKM1) autoantibodies directed against the cytochrome P450 2D6 (CYP2D6) are considered specific markers of type 2 autoimmune hepatitis, but are also found in 5% of sera from patients chronically infected by hepatitis C virus (HCV). Molecular mimicry between HCV proteins and CYP2D6 has been proposed to explain the emergence of these autoantibodies. Anti-LKM1 autoantibodies from hepatitis C-infected patients were affinity-purified against immobilized CYP2D6 protein and used to screen a phage display library. CYP2D6 conformational epitopes were identified using phage display analysis and the identification of statistically significant pairs (SSPs). Cross-reactivity between CYP2D6 and HCV protein candidates was tested by immunoprecipitation. Nineteen different clones were isolated, and their sequencing resulted in the mapping of a conformational epitope to the region of amino acids 254-288 of CYP2D6. Candidate HCV proteins for molecular mimicry included: core, E2, NS3 and NS5a. Affinity-purified autoantibodies from HCV+/LKM1+ patients immunoprecipitated either NS3, NS5a, or both, and these reactivities were specifically inhibited by immobilized CYP2D6. In conclusion, HCV+/LKM1+ sera recognize a specific conformational epitope on CYP2D6 between amino acids 254 to 288, the region that contains the major linear epitope in type 2 autoimmune hepatitis patients. Cross-reactivity due to molecular mimicry at the B-cell level was shown between the CYP2D6 and the HCV NS3 and NS5a proteins and could explain the presence of anti-LKM1 in patients chronically infected with HCV. Further investigation of the role played by this molecular mimicry in HCV-infected patients may lead to more specific strategies for diagnosis and treatment.

Management of hepatitis C virus-related arthritis

In recent years, hepatitis C virus-related arthritis (HCVrA) has been recognised as an autonomous rheumatic disorder. Two subsets of the disease have been identified: a polyarthritis involving small joints that resembles rheumatoid arthritis, but is usually milder, and a mono-oligoarthritis that shows an intermittent course and is frequently associated with the presence of cryo-globulins in serum. Few data about HCVrA treatment are reported in the literature. As a consequence, the therapeutic approach for this disorder is still largely empirical. Hydroxychloroquine, low doses of corticosteroids and NSAIDs are frequently administered to patients with HCVrA, but some authors describe an incomplete relief of symptoms, especially in the rheumatoid-like subset. Intake of low doses of corticosteroids and NSAIDs is more effective in subjects belonging to the mono-oligoarthritis group. Use of antiviral drugs (IFN plus ribavirin) shows good results, but IFN can induce or worsen autoimmune disorders. For this reason, in our opinion, this approach should be prescribed only when required by the coexistent liver disease. On the basis of the poor available data, the administration of anti-TNF-alpha agents seems safe in HCV patients, but the usually non-aggressive course of HCVrA does not justify their use as a current therapy.

Consequence or coincidence? The occurrence, pathogenesis and significance of autoimmune manifestations after viral vaccines

BACKGROUND

Viruses and virus-induced lymphokines may have an important role in the pathogenesis of autoimmunity (Schattner A. Clin Immunol Immunopathol; 1994). The occurrence and significance of autoimmune manifestations after the administration of viral vaccines remain controversial.

METHODS

Medline search of all relevant publications from 1966 through June 2004 with special emphasis on search of each individual autoimmune manifestation and vaccination, as well as specifically searching each viral vaccine for all potential autoimmune syndromes reported. All relevant publications were retrieved and critically analyzed.

RESULTS

The most frequently reported autoimmune manifestations for the various vaccinations, were: hepatitis A virus (HAV)--none; hepatitis B virus (HBV)--rheumatoid arthritis, reactive arthritis, vasculitis, encephalitis, neuropathy, thrombocytopenia; measles, mumps and rubella vaccine (MMR)--acute arthritis or arthralgia, chronic arthritis, thrombocytopenia; influenza--Guillain-Barre syndrome (GBS), vasculitis; polio--GBS; varicella--mainly neurological syndromes. Even these 'frequent' associations relate to a relatively small number of patients. Whenever controlled studies of autoimmunity following viral vaccines were undertaken, no evidence of an association was found.

CONCLUSIONS

Very few patients may develop some autoimmune diseases following viral vaccination (in particular - arthropathy, vasculitis, neurological dysfunction and thrombocytopenia). For the overwhelming majority of people, vaccines are safe and no evidence linking viral vaccines with type 1 diabetes, multiple sclerosis (MS) or inflammatory bowel disease can be found.

Remission of natural-killer cell lymphoma of the liver with anti-hepatitis C therapy

Non-Hodgkin lymphomas (NHL) consist of a diverse group of lymphoproliferative neoplasms with unique patterns of biology, behavior, and differing responses to therapy. A rare subtype of malignancy arising from cells of putative natural killer (NK) origin is being recognized as a distinct clinicopathological entity. Viruses including hepatitis C have been reported in association with various types of NHL but not the NK-cell subtype. We hereby report a unique case of a patient with hepatitis C who developed hepatic NK-cell lymphoma and chronic NK-cell leukemia. Interestingly, we observed clinical and radiologic remission of the neoplasm following treatment with anti-hepatitis C therapy.

Children with hepatitis C

Hepatitis C affects thousands of children throughout the world. Most children acquire the virus through vertical transmission, although parenteral routes of acquisition are also common. Hepatitis C progresses slowly, with mild biopsy findings and no symptoms in most children and in many adults. However, significant liver inflammation and fibrosis can occur in childhood. Trials of antiviral therapy with interferon and ribavirin have shown these drugs to be effective in almost half of the children treated. Children tend to tolerate therapy well. Further research on the natural history and treatment of hepatitis C in children is needed because the infection can have serious long-term consequences, including end-stage liver disease and hepatocellular carcinoma.

Novel insights into hepatitis C virus replication and persistence

Hepatitis C virus (HCV) is a small enveloped RNA virus that belongs to the family Flaviviridae. A hallmark of HCV is its high propensity to establish a persistent infection that in many cases leads to chronic liver disease. Molecular studies of the virus became possible with the first successful cloning of its genome in 1989. Since then, the genomic organization has been delineated, and viral proteins have been studied in some detail. In 1999, an efficient cell culture system became available that recapitulates the intracellular part of the HCV life cycle, thereby allowing detailed molecular studies of various aspects of viral RNA replication and persistence. This chapter attempts to summarize the current state of knowledge in these most actively worked on fields of HCV research.

TNF-{alpha}, chronic hepatitis C and diabetes: a novel triad

Patients with chronic hepatitis C virus (HCV) infection have a significantly increased prevalence of type 2 DM compared to controls or HBV-infected patients, independent of the presence of cirrhosis. Moreover, antecedent HCV infection markedly increases the risk of developing DM in susceptible subjects. Even non-diabetic HCV patients have insulin resistance and specific defects in the insulin-signalling pathway. Activation of the tumour necrosis factor (TNF)-alpha system has a pivotal role in the inflammatory process of chronic hepatitis C, and TNF-alpha levels correlate with the degree of inflammation. TNF-alpha is known to cause insulin resistance, with similar defects in the insulin signalling pathway to those described in HCV infection. A model of mice transgenic for the HCV core protein demonstrated insulin resistance, glucose intolerance, and elevated intrahepatic TNF-alpha mRNA; all of which were ameliorated by anti-TNF-alpha antibodies. In addition, diabetic HCV patients have significantly higher levels of soluble TNF-alpha receptors, compared to non-diabetic HCV patients and controls. TNF-alpha may be the link between HCV infection and diabetes, suggesting an additional mechanism of diabetes with important implications for prognosis and therapy.

Core protein of hepatitis C virus induces cardiomyopathy

Hepatitis C virus (HCV) has been reported to be associated with cardiomyopathy. However, the mechanism of cardiomyopathy in chronic HCV infection is still unclear. Therefore, we investigate the development of cardiomyopathy in mice transgenic for the HCV-core gene. After the age of 12 months, mice developed cardiomyopathy that appeared as left ventricular dilatation, and systolic and diastolic dysfunction assessed by Doppler echocardiography. Histologically, hypertrophy of cardiomyocytes, cardiac fibrosis, disarray and scarcity of myofibrils, vacuolization and deformity of nuclei, myofibrillar lysis, streaming of Z-bands, and an increased number of bizarre-shaped mitochondria were found in HCV-core transgenic mice. These histological changes are just consistent with cardiomyopathy. In conclusion, the HCV-core protein directly plays an important role in the development of cardiomyopathy.

Hepatitis C virus-associated extrahepatic manifestations: a review

The hepatitis C virus (HCV) infection is a worldwide disease that is characterized by a preferential chronic evolution with mild to severe liver disease, including cirrhosis and, in lesser proportion, hepatocarcinoma. Out of these complications, HCV is frequently reported to complicate extrahepatic manifestations. Among those associated to HCV infection with a high degree of certainty, mixed cryoglobulinemia and its complications (skin, neurological, renal, rheumatological involvement) are the most prevalent (50%) in HCV-infected patients. The other diseases include noncryoglobulinemic systemic vasculitis, splenic lymphoma with villous lymphocytes, fatigue, porphyria cutanea tarda, sicca syndrome, and autoantibodies production. The extrahepatic manifestations that share mild-degree certainty of association with HCV infection include B-cell non-Hodgkin lymphoma, autoimmune thrombocytopenia, pruritus, and type II diabetes mellitus. The other diseases such as autoimmune thyroiditis, lichen planus are more questionable for their eventual association with HCV and others (pulmonary fibrosis with or without polymyositis, progressive encephalomyelitis, Mooren's corneal ulcers, erythema nodosum, chronic polyradiculonevritis) are mostly case reports. Howerver, even in cases of tight association, the mechanisms through which HCV may promote or induce extrahepatic manifestations remain unclear and merit further investigations.

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Desquamative Interstitial Pneumonia and Hepatitis C Virus Infection: A Rare Association

Extrahepatic manifestations of hepatitis C virus (HCV) infection are common. The authors report the unusual occurrence of desquamative interstitial pneumonia (DIP) in a patient with HCV. An immunologic response to HCV infection may have a role in the pathogenesis of DIP in patients with chronic HCV. Since DIP is treatable, HCV patients with pulmonary infiltrates should be thoroughly investigated for this disorder. In our experience, the use of steroids in HCV-associated DIP improved the patient's respiratory status without increasing the viral load.

Hepatitis C infection and type 2 diabetes in American-Indian women

OBJECTIVE

The aim of this study was to describe the association between hepatitis C virus (HCV) infection and type 2 diabetes among a group of American-Indian women who were screened for both conditions.

RESEARCH DESIGN AND METHODS

The study population was a convenience sample of women who were receiving prenatal care. All women were systematically screened for both HCV and diabetes.

RESULTS

A total of 426 women were included in the sample. HCV infection was detected in 13 (3.1% [95% CI 1.7-5.0]) and type 2 diabetes in 22 (5.2%, [3.3-7.6]) women. Women diagnosed with type 2 diabetes were more obese and had higher serum alanine aminotransferase activity compared with women without diabetes. Four of 13 (30.8% [10.6-58.7]) HCV-infected women and 18 of 413 (4.4% [2.7-6.7]) women without evidence of HCV infection had type 2 diabetes. (odds ratio 9.8 [95% CI 2.4-34.0], Fisher's exact test P = 0.003). In a logistic regression model, increasing age (10-year increments), obesity (by standard deviations from the mean BMI), and positive HCV status were each independently related to the diagnosis of diabetes.

CONCLUSIONS

Among American-Indian women, type 2 diabetes is more common in those with than in those without HCV infection. This association and its potential mechanisms may have clinical implications. Investigation into the mechanisms linking HCV infection to the expression of type 2 diabetes may also help to define processes that promote the development of type 2 diabetes in susceptible individuals.

Xerostomia: clinical aspects and treatment

Xerostomia or dry mouth is a condition that is frequently encountered in dental practice. The most common cause is the use of certain systemic medications, which make the elderly at greater risk because they are usually more medicated. Other causes include high doses of radiation and certain diseases such as Sjogren's syndrome. Xerostomia is associated with difficulties in chewing, swallowing, tasting or speaking. This results in poor diet, malnutrition and decreased social interaction. Xerostomia can cause oral discomfort, especially for denture wearers. Patients are at increased risk of developing dental caries. A thorough intraoral and extra-oral clinical examination is important for diagnosis. Treatment may include the use of salivary substitutes (Biotene), salivary stimulants such as pilocarpine, ongoing dental care, caries prevention, a review of the current prescription drug regimen and possible elimination of drugs having anticholinergic effects. Because of the ageing population, and the concomitant increase in medicated individuals, dentists can expect to be presented with xerostomia in an increasing number of patients in the coming years and therefore should be familiar with its diagnosis and treatment. Therefore, the purpose of this review is to outline for clinicians the common aetiologies, clinical identification, and routine therapeutic modalities available for individuals with xerostomia.

Sarcoidosis in untreated chronic hepatitis C virus infection

Chronic hepatitis C has been implicated in the pathogenesis of sarcoidosis in several cases of patients treated with interferon-alpha. On the other hand, only in a few cases previously has a possible link between sarcoidosis and untreated chronic hepatitis C virus infection been demonstrated. We report on a patient with chronic hepatitis C who developed cutaneous sarcoidosis without prior interferon-alpha treatment. We hypothesize that viral persistence seen in chronic hepatitis C virus infection might be one of the potential factors that trigger cellular immune response in granulomatous reactions as seen in sarcoidosis, in genetically predisposed patients.