Longitudinal Sequence and Functional Evolution within Glycoprotein E2 in Hepatitis C Virus Genotype 3a Infection

The E2 glycoprotein of Hepatitis C virus (HCV) is a major target of the neutralizing antibody (NAb) response with the majority of epitopes located within its receptor binding domain (RBD; 384–661). Within E2 are three variable regions located at the N-terminus (HVR1; 384–411), and internally at 460–480 (HVR2) and 570–580 [intergenotypic variable region (igVR)], all of which lie outside a conserved core domain that contains the CD81 binding site, essential for attachment of virions to host cells and a major target of NAbs. In this study, we examined the evolution of the E1 and E2 region in two patients infected with genotype 3a virus. Whereas one patient was able to clear the acute infection, the other developed a chronic infection. Mutations accumulated at multiple positions within the N-terminal HVR1 as well as within the igVR in both patients over time, whereas mutations in HVR2 were observed only in the chronically infected patient. Mutations within or adjacent to the CD81 contact site were observed in both patients but were less frequent and more conservative in the patient that cleared his/her infection. The evolution of CD81 binding function and antigenicity was examined with longitudinal E2 RBD sequences. The ability of the RBD to bind CD81 was completely lost by week 108 in the patient that developed chronic HCV. In the second patient, the ability of the week 36 RBD, just prior to viral clearance, to bind CD81 was reduced ~50% relative to RBD sequences obtained earlier. The binding of a NAb specific to a conserved epitope located within E2 residues 411–428 was significantly reduced by week 108 despite complete conservation of its epitope suggesting that E2 antigenicity is allosterically modulated. The exposure of non-neutralizing antibody epitopes was similarly explored and we observed that the epitope of 3 out of 4 non-NAbs were significantly more exposed in the RBDs representing the late timepoints in the chronic patient. By contrast, the exposure of non-neutralizing epitopes was reduced in the patient that cleared his/her infection and could in part be attributed to sequence changes in the igVR. These studies reveal that during HCV infection, the exposure of the CD81 binding site on E2 becomes increasingly occluded, and the antigenicity of the E2 RBD towards both neutralizing and non-neutralizing antibodies is modulated via allosteric mechanisms.     

乙型肝炎病人尿细胞中HBV的实验研究

本文采用间接免疫荧光法（ＩＦ）,ＲＰＨＡ法,ＥＬＩＳＡ法及斑点杂交技术检测１０例无症状ＨＢ－ｓＡｇ携带者及８９例乙肝病人尿细胞中的ＨＢｓＡｇ、ＨＢｅＡｇ及ＨＢＶＤＮＡ,发现尿细胞中有ＨＢｓＡｇ、ＨＢｅＡｇ、ＨＢＶＤＮＡ存在。结果提示：乙肝无症状携带者及乙肝病人尿细胞中具有ＨＢｓＡｇ、ＨＢｅＡｇ、ＨＢＶＤＮＡ,因此更进一步证实尿液具有传染性。     

Enhanced HBsAg Synthesis Correlates with Increased Severity of Fibrosis in Chronic Hepatitis B Patients

Background and Aims

Little is known about whether low serum HBsAg levels result from impaired HBsAg synthesis or a reduced number of hepatocytes caused by advanced liver fibrosis. Therefore, we investigated the capacity for HBsAg synthesis in a cross-sectional cohort of treatment-naïve chronic hepatitis B patients.

Methods

Chronic hepatitis B patients (n = 362) were enrolled; liver biopsies were performed and liver histology was scored, and serum HBsAg and HBV DNA levels were investigated. In the enrolled patients, 183 out of 362 have quantitative serum HBsAg levels. Tissue HBsAg was determined by immunohistochemistry.

Results

A positive correlation between serum HBsAg and HBV DNA levels was revealed in HBeAg(+) patients (r = 0.2613, p = 0.0050). In HBeAg(+) patients, serum HBsAg and severity of fibrosis were inversely correlated (p = 0.0094), whereas tissue HBsAg levels correlated positively with the stage of fibrosis (p = 0.0280). After applying the mean aminopyrine breath test as a correction factor, adjusted serum HBsAg showed a strong positive correlation with fibrosis severity in HBeAg(+) patients (r = 0.5655, p<0.0001). The adjusted serum HBsAg values predicted ‘moderate to severe’ fibrosis with nearly perfect performance in both HBeAg(+) patients (area under the curve: 0.994, 95% CI: 0.983–1.000) and HBeAg(−) patients (area under the curve: 1.000, 95% CI: 1.000–1.000).

Conclusions

Although serum HBsAg levels were negatively correlated with fibrosis severity in HBeAg(+) patients, aminopyrine breath test-adjusted serum HBsAg and tissue HBsAg, two indices that are unaffected by the number of residual hepatocytes, were positively correlated with fibrosis severity. Furthermore, adjusted serum HBsAg has an accurate prediction capability.     

靖江地区宫颈病变患者高危型人乳头瘤病毒感染及其基因型分析

目的:研究靖江地区各组宫颈病变中高危型人乳头瘤病毒(HPV)感染率及其基因型分布。方法:采用实时荧光PCR检测方法检测334例宫颈脱落细胞标本中高危型HPV及其基因型。结果:高危型HPV在宫颈炎组、湿疣组、低度鳞状上皮细胞内病变(LSIL)组、高度鳞状上皮细胞内病变(HSIL)组中的感染率分别为24.2%、58.2%、49.3%、69.5%;HPV 16、18、33、58型在宫颈病变中是最常见的HPV型别,其中,HPV16型在宫颈炎组、湿疣组、LSIL组、HSIL组中所占比例逐渐增高,分别为17.9%、18.9%、30.8%、41.9%。结论:高危型HPV感染率随着宫颈病变程度的加重而升高,HPV16型是高危型HPV感染中的主要亚型,HPV18、33、52、58也较常见,其余型别很少。     

靖江地区宫颈病变患者高危型人乳头瘤病毒感染及其基因型分析

目的：研究靖江地区各组宫颈病变中高危型人乳头瘤病毒（HPV）感染率及其基因型分布。方法：采用实时荧光PCR检测方法检测334例宫颈脱落细胞标本中高危型HPV及其基因型。结果：高危型HPV在宫颈炎组、湿疣组、低度鳞状上皮细胞内病变（LSIL）组、高度鳞状上皮细胞内病变（HSIL）组中的感染率分别为24.2%、58.2%、49.3%、69.5%;HPV 16、18、33、58型在宫颈病变中是最常见的HPV型别,其中,HPV16型在宫颈炎组、湿疣组、LSIL组、HSIL组中所占比例逐渐增高,分别为17.9%、18.9%、30.8%、41.9%。结论：高危型HPV感染率随着宫颈病变程度的加重而升高,HPV16型是高危型HPV感染中的主要亚型,HPV18、33、52、58也较常见,其余型别很少。     

Genetic Variation in Interleukin 28B and Response to Antiviral Therapy in Patients with Dual Chronic Infection with Hepatitis B and C Viruses

Concurrent infection with hepatitis C virus (HCV) and hepatitis B virus (HBV) was not uncommon in China. To date, information on predictors of response to treatment of dually-infected HCV/HBV is limited. The aim of this study was to evaluated whether determination of the interleukin 28B (IL-28B) polymorphism statuses sufficient to predict treatment response of interferon (IFN)-based therapy in patients chronically infected with both hepatitis B and C viruses. We investigated the role of IL28B variations (rs8099917 and rs12979860) in response to IFN-based treatment and evaluated its association with the risk of the null virological response (NVR) in HCV /HBV dually-infected patients. We found that the overall distributions of the genotypes among the sustained virological response (SVR), NVR groups were significantly different (P<0.001): patients with the rs8099917 TG genotype had an increased risk of NVR (odds ratio [OR] =2.37 95% confidence interval [CI] =1.16–4.83, P =0.017), and those with the GG genotype had a further increased risk of NVR (OR=4.23, 95% CI =1.17-15.3, P=0.027). The rs12979860 allele was also highly associated with treatment failure (CT/TT vs. CC; OR =2.04, 95%CI =1.05-3.97, P =0.037). Moreover, we found that IL28B rs8099917 G variants (TG+GG) interact with HCV genotype 1(G1) to result in higher risk of NVR (P=0.009), and that they are also associated with HBV DNA reactivation (TG+GG vs. TT, P=0.005). Furthermore, multivariate regression analysis show that the rs8099917 G allele was the most important factor significantly associated with a NVR in HCV G1 patients. This study suggest that IL28B genotyping may be a valid pretreatment predictor of which patients are likely to respond to treatment in this group of difficult-to-treat HCV/HBV dually-infected patients.     

乙型肝炎IgA类HBsAg循环免疫复合物的检测及意义

本文报道用捕捉法ELISA检测各型乙肝IgA型HBsAg循环免疫复合物。结果表明,慢性乙肝IgA型HBsAg循环免疫复合物检出率显著高于急性乙肝;在慢性乙肝中,IgA型HBsAg循环免疫复合物的出现与HBVe系统关系密切,主要存在于HBeAg阳性血清中,并与HBeAg滴度有关。故IgA型HBsAg循环免疫复合物可作为HBV慢性感染的血清诊断标志之一;也可作为反映HBV在增殖并有传播危险的标志之一。     

Distinct Distribution Pattern of Hepatitis B Virus Genotype C and D in Liver Tissue and Serum of Dual Genotype Infected Liver Cirrhosis and Hepatocellular Carcinoma Patients

Aims

The impact of co-infection of several hepatitis B virus (HBV) genotypes on the clinical outcome remains controversial. This study has for the first time investigated the distribution of HBV genotypes in the serum and in the intrahepatic tissue of liver cirrhotic (LC) and hepatocellular carcinoma (HCC) patients from India. In addition, the genotype-genotype interplay and plausible mechanism of development of HCC has also been explored.

Methods

The assessment of HBV genotypes was performed by nested PCR using either surface or HBx specific primers from both the circulating virus in the serum and replicative virus that includes covalently closed circular DNA (cccDNA) and relaxed circular DNA (rcDNA) of HBV from the intrahepatic tissue. The integrated virus within the host chromosome was genotyped by Alu-PCR method. Each PCR products were cloned and sequences of five randomly selected clones were subsequently analysed.

Results

HBV/genotype D was detected in the serum of all LC and HCC patients whereas the sequences of the replicative HBV DNA (cccDNA and rcDNA) from the intrahepatic tissue of the same patients revealed the presence of both HBV/genotype C and D. The sequences of the integrated viruses exhibited the solo presence of HBV/genotype C in the majority of LC and HCC tissues while both HBV/genotype C and D clones were found in few patients in which HBV/genotype C was predominated. Moreover, compared to HBV/genotype D, genotype C had higher propensity to generate double strand breaks, ER stress and reactive oxygen species and it had also showed higher cellular homologous-recombination efficiency that engendered more chromosomal rearrangements, which ultimately led to development of HCC.

Conclusions

Our study highlights the necessity of routine analysis of HBV genotype from the liver tissue of each chronic HBV infected patient in clinical practice to understand the disease prognosis and also to select therapeutic strategy.     

Genotype Distribution,Viral Load and Clinical Characteristics of Infants with Postnatal or Congenital Cytomegalovirus Infection

Background

Congenital cytomegalovirus infection is a leading cause of long-term sequelae. Cytomegalovirus is also frequently transmitted to preterm infants postnatally, but these infections are mostly asymptomatic. A correlation between cytomegalovirus genotypes and clinical manifestations has been reported previously in infants with congenital infection, but not in preterm infants with postnatal infection.

Objectives

The main objective of this study was to investigate cytomegalovirus genotype distribution in postnatal and congenital cytomegalovirus infection and its association with disease severity.

Methods

Infants admitted to the neonatal intensive care unit of the University Medical Center Utrecht, The Netherlands between 2003–2010 and diagnosed with postnatal or congenital cytomegalovirus infection were included. Classification of cytomegalovirus isolates in genotypes was performed upon amplification and sequencing of the cytomegalovirus UL55 (gB) and UL144 genes. Clinical data, cerebral abnormalities, neurodevelopmental outcome and viral load were studied in relation to genotype distribution.

Results

Genotyping results were obtained from 58 preterm infants with postnatal cytomegalovirus infection and 13 infants with congenital cytomegalovirus infection. Postnatal disease was mild in all preterm infants and all had favourable outcome. Infants with congenital infection were significantly more severely affected than infants with postnatal infection. Seventy-seven percent of these infants were symptomatic at birth, 2/13 died and 3/13 developed long-term sequelae (median follow-up 6 (range 2–8) years). The distribution of cytomegalovirus genotypes was comparable for postnatal and congenital infection. UL55 genotype 1 and UL144 genotype 3 were predominant genotypes in both groups.

Conclusions

Distribution of UL55 and UL144 genotypes was similar in asymptomatic postnatal and severe congenital CMV infection suggesting that other factors rather than cytomegalovirus UL55 and UL144 genotype are responsible for the development of severe disease.     

Association between CXCL10 and DPP4 Gene Polymorphisms and a Complementary Role for Unfavorable IL28B Genotype in Prediction of Treatment Response in Thai Patients with Chronic Hepatitis C Virus Infection

Pretreatment serum levels of interferon-γ-inducible protein-10 (IP-10, CXCL10) and dipeptidyl peptidase-4 (DPP IV) predict treatment response in chronic hepatitis C (CHC). The association between functional genetic polymorphisms of CXCL10 and DPP4 and treatment outcome has not previously been studied. This study aimed to determine the association between genetic variations of CXCL10 and DPP4 and the outcome of treatment with pegylated interferon-α (PEG-IFN-α) based therapy in Thai patients with CHC. 602 Thai patients with CHC treated using a PEG-IFN-α based regimen were genotyped for CXCL10 rs56061981 G>A and IL28B rs12979860 C>T. In addition, in patients infected with CHC genotype 1, DPP4 (rs13015258 A>C, rs17848916 T>C, rs41268649 G>A, and rs 17574 T>C) were genotyped. Correlations between single nucleotide polymorphisms, genotype, and treatment response were analyzed. The rate of sustained virologic response (SVR) was higher for the CC genotype of IL28B rs12979860 polymorphisms than for non-CC in both genotype 1 (60.6% vs. 29.4%, P < 0.001) and non-genotype 1 (69.4% vs. 49.1%, P < 0.05) CHC. SVR was not associated with the CXCL10 gene variant in all viral genotypes or DPP4 gene polymorphisms in viral genotype1. Multivariate analysis revealed IL28B rs12979860 CC genotype (OR = 3.12; 95% CI, 1.72–5.67; P < 0.001), hepatitis C virus RNA < 400,000 IU/ml (OR = 2.21; 95% CI, 1.22–3.99, P < 0.05), age < 45 years (OR = 2.03; 95% CI, 1.11–3.68; P < 0.05), and liver fibrosis stage 0–1 (OR = 1.64; 95% CI, 1.01–2.65, P < 0.05) were independent factors for SVR. Unfavorable IL28B rs12979860 CT or TT genotypes with the CXCL10 rs56061981 non-GG genotype were associated with a higher SVR than GG genotype (66.7% vs. 33.0%, P = 0.004) in viral genotype 1. In Thai CHC genotype 1 infected patients with an unfavorable IL28B rs12979860 CT/TT genotype, the complementary CXCL10 polymorphism strongly enhances prediction of treatment response.     

Genotype Distribution of Vitamin D Receptor Polymorphisms among Indonesian Patients with Chronic Hepatitis B

Background:Chronic hepatitis B is a necro-inflammatory of the liver parenchyma caused by hepatitis B virus (HBV) infection leading to liver cirrhosis and hepatocellular carcinoma (HCC). Genetic variants including single nucleotide polymorphisms (SNPs) within genes regulating immune response may contribute to the progression of chronic hepatitis B (CHB) infection. This study aimed to examine the genotype distribution of vitamin D receptor (VDR) polymorphism among patients with CHB infection and to study its association with the development of cirrhosis and hepatoma.Methods:This cross-sectional study analysed 75 CHB patients, consisting of 36 CHB patients without cirrhosis, 25 CHB patients with cirrhosis, and 14 CHB patients with hepatoma. VDR polymorphism was examined using the Amplification Refractory Mutation System Polymerase Chain Reaction (ARMS-PCR) method.Results:Alanine aminotransferase (ALT) and alpha fetoprotein (AFP) levels did not show any significant differences between study groups, but albumin levels in CHB patients with cirrhosis and hepatoma were significantly lower than CHB patients without cirrhosis (p< 0.05). In contrast, the bilirubin levels in CHB patients with cirrhosis was higher than in CHB patients’ cirrhosis. The most common genotypes of VDR polymorphisms were Ff (57.3%), TT (72%), aa (48%) and bb (74.7%) for Fok1, Taq1, Apa1 and Bsm1 respectively. There was no significant different in the genotype distribution of VDR polymorphism between CHB patients without cirrhosis and CHB with cirrhosis or hepatoma. Conclusion:This study suggest that VDR gene polymorphism may not contribute to the progression of CHB infection.Key Words: Cirrhosis, Hepatitis B, Hepatoma, Polymorphism, Vitamin D Receptor     

Host Genetic Factors Affecting Spontaneous HBsAg Seroclearance in Chronic Hepatitis B Patients

Spontaneous clearance of hepatitis B surface antigen (HBsAg) in chronic hepatitis B (CHB) patients usually indicates a remission of hepatitis activity and a favorable outcome. Two single nucleotide polymorphisms (SNP), rs3077 near HLA-DPA1 region and rs9277535 near HLA-DPB1 region, have been shown to be associated with HBV persistence after acute HBV infection. However, little is known about the impact of these 2 SNPs on spontaneous HBsAg clearance in CHB patients. In this case-control study, a total of 100 male HBeAg-negative chronic HBV carriers who cleared HBsAg spontaneously (case group) and 100 age-matched HBeAg-negative male patients with persistent HBsAg positivity (control group) were enrolled. We investigated the relationship between these 2 SNPs and HBsAg clearance. There was a higher frequency of rs9277535 non-GG genotype in the case group (57% vs. 42%). Patients with rs9277535 non-GG genotype had a higher chance to clear HBsAg [Odds ratio (OR): 1.83, 95% confidence interval (CI): 1.04∼3.21, P = 0.034]. Compared to GG haplotype of rs3077 and rs9277535, GA haplotype had a higher chance of achieving spontaneous HBsAg loss (OR: 2.17, 95% CI: 1.14∼4.16, P = 0.030). In conclusion, rs9277535 non-GG genotype is associated with a higher likelihood of spontaneous HBsAg seroclearance in CHB patients.     

Clinical and Virological Characteristics of Chronic Hepatitis B Patients with Coexistence of HBsAg and Anti-HBs

Coexistence of hepatitis B surface antigen (HBsAg) and antibody against HBsAg (anti-HBs) comprises an atypical serological profile in patients with chronic hepatitis B virus (HBV) infection. In this study, in total 94 patients with coexisting HBsAg and anti-HBs and 94 age- and sex-matched patients with positive HBsAg were characterized by quantitatively measuring HBsAg and HBV DNA, sequencing large S genes, and observing clinical features. Compared with common hepatitis B patients, the patients with coexisting HBsAg and anti-HBs had lower HBsAg and HBV DNA levels. These two groups had similar rate of pre-S deletion mutations. However, in patients with coexisting HBsAg and anti-HBs, more amino acid substitutions in the a determinant of S gene were observed in HBV genotype C, but not in genotype B. Fourteen patients with coexisting HBsAg and anti-HBs were followed up for an average of 15.5 months. There were no significant changes in the levels of HBsAg, anti-HBs, HBV DNA and ALT over the follow-up period. Compared with the baseline sequences, amino acid substitutions in the MHR of HBsAg occurred in 14.3% (2/14) patients. In conclusion, coexistence of HBsAg and anti-HBs may be associated with higher frequency of mutations in the a determinant of HBV genotype C.     

Longitudinal Liver Stiffness Assessment in Patients with Chronic Hepatitis C Undergoing Antiviral Therapy

Background/Aims

Liver stiffness (LS) measurement by means of transient elastography (TE) is accurate to predict fibrosis stage. The effect of antiviral treatment and virologic response on LS was assessed and compared with untreated patients with chronic hepatitis C (CHC).

Methods

TE was performed at baseline, and at weeks 24, 48, and 72 in 515 patients with CHC.

Results

323 treated (62.7%) and 192 untreated patients (37.3%) were assessed. LS experienced a significant decline in treated patients and remained stable in untreated patients at the end of study (P<0.0001). The decline was significant for patients with baseline LS ≥ 7.1 kPa (P<0.0001 and P 0.03, for LS ≥9.5 and ≥7.1 kPa vs lower values, respectively). Sustained virological responders and relapsers had a significant LS improvement whereas a trend was observed in nonresponders (mean percent change −16%, −10% and −2%, for SVR, RR and NR, respectively, P 0.03 for SVR vs NR). In multivariate analysis, high baseline LS (P<0.0001) and ALT levels, antiviral therapy and non-1 genotype were independent predictors of LS improvement.

Conclusions

LS decreases during and after antiviral treatment in patients with CHC. The decrease is significant in sustained responders and relapsers (particularly in those with high baseline LS) and suggests an improvement in liver damage.     

Inflammation and Liver Cell Death in Patients with Hepatitis C Viral Infection

Hepatitis C virus (HCV)-induced liver disease contributes to chronic hepatitis. The immune factors identified in HCV include changes in the innate and adaptive immune system. The inflammatory mediators, known as “inflammasome”, are a consequence of the metabolic products of cells and commensal or pathogenic bacteria and viruses. The only effective strategy to prevent disease progression is eradication of the viral infection. Immune cells play a pivotal role during liver inflammation, triggering fibrogenesis. The present paper discusses the potential role of markers in cell death and the inflammatory cascade leading to the severity of liver damage. We aim to present the clinical parameters and laboratory data in a cohort of 88 HCV-infected non-cirrhotic and 25 HCV cirrhotic patients, to determine the characteristic light microscopic (LM) and transmission electron microscopic (TEM) changes in their liver biopsies and to present the link between the severity of liver damage and the serum levels of cytokines and caspases. A matched HCV non-infected cohort was used for the comparison of serum inflammatory markers. We compared the inflammation in HCV individuals with a control group of 280 healthy individuals. We correlated the changes in inflammatory markers in different stages of the disease and the histology. We concluded that the serum levels of cytokine, chemokine, and cleaved caspase markers reveal the inflammatory status in HCV. Based upon the information provided by the changes in biomarkers the clinician can monitor the severity of HCV-induced liver damage. New oral well-tolerated treatment regimens for chronic hepatitis C patients can achieve cure rates of over 90%. Therefore, using the noninvasive biomarkers to monitor the evolution of the liver damage is an effective personalized medicine procedure to establish the severity of liver injury and its repair.     

Virological Predictors of Response to Retreatment in Hepatitis C Genotype 2 Infected Patients

Background/Aims

The impact of virological factors and interleukin-28B (IL-28B) genetic variants on retreatment of hepatitis C virus genotype 2 (HCV-2) treatment-experienced patients remains unknown.

Methods

On-treatment virological responses and IL-28B rs8099917 genotype were determined in 46 HCV-2 treatment-experienced patients (42 previous relapsers; four previous non-responders) retreated with 24-week peginterferon/ribavirin.

Results

Forty (87.0%) patients carried the rs8099917 TT genotype and 6 patients (13.0%) carried the TG/GG genotype. The sustained virological response (SVR; seronegativity of HCV RNA throughout 24 weeks of the post-treatment follow-up period) rate was 71.7%. Compared with previous non-responders, previous relapsers had a significantly higher SVR rate (78.6% vs. 0%, P = 0.004) and a lower relapse rate (17.5% vs. 100%, P = 0.04). All the previous non-responders were with the rs8099917 TT genotype. As for those who relapsed, treatment responses, including the rates of rapid virological response (RVR, 80.6% vs. 66.7%, P = 0.59), early virological response (EVR, 97.2% vs. 83.3%, P = 0.27), end-of-treatment virological response (97.2% vs. 83.3%, P = 0.27) and SVR (80.6% vs. 66.7%, P = 0.59) and relapse rate (17.1% vs. 20.0%, P = 1) did not differ significantly between patients with the rs8099917 TT and those with the non-TT genotype. Multivariate analysis revealed that the most important factor predictive of an SVR in the retreatment of HCV-2 was previous relapse; the only factor predictive of an SVR for previous relapsers was the achievement of an EVR. Compared with the achievement of a RVR, the attainment of an EVR was more accurate in predicting an SVR (88% vs. 74%).

Conclusions

Peginterferon/ribavirin is effective in the retreatment of HCV-2 relapsers, especially among those who achieved an EVR.     

Altered Functionality of Anti-Bacterial Antibodies in Patients with Chronic Hepatitis C Virus Infection

Background

Using comparative glycoproteomics, we have previously identified a glycoprotein that is altered in both amount and glycosylation as a function of liver cirrhosis. The altered glycoprotein is an agalactosylated (G0) immunoglobulin G molecule (IgG) that recognizes the heterophilic alpha-gal epitope. Since the alpha gal epitope is found on gut enterobacteria, it has been hypothesized that anti-gal antibodies are generated as a result of increased bacterial exposure in patients with liver disease.

Methods

The N-linked glycosylation of anti-gal IgG molecules from patients with fibrosis and cirrhosis was determined and the effector function of anti-bacterial antibodies from over 100 patients examined. In addition, markers of microbial exposure were determined.

Results

Surprisingly, the subset of agalactosylated anti-gal antibodies described here, was impaired in their ability to mediate complement mediated lysis and inhibited the complement-mediated destruction of common gut bacteria. In an analysis of serum from more than 100 patients with liver disease, we have shown that those with increased levels of this modified anti-gal antibody had increased levels of markers of bacterial exposure.

Conclusions

Anti-gal antibodies in patients with liver cirrhosis were reduced in their ability to mediate complement mediated lysis of target cells. As bacterial infection is a major complication in patients with cirrhosis and bacterial products such as LPS are thought to play a major role in the development and progression of liver fibrosis, this finding has many clinical implications in the etiology, prognosis and treatment of liver disease.