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Virus Carriers (virus + carrier)
Selected AbstractsVariants of two major T cell epitopes within the hepatitis B surface antigen are not recognized by specific T helper cells of vaccinated individualsHEPATOLOGY, Issue 2 2002Tanja Bauer Several naturally occurring variants of immunogenic T cell epitopes were identified within the hepatitis B surface antigen (HBsAg). The effect of these variants on the cellular immune response was studied in individuals vaccinated against HBV. Class-II restricted T-cell responses of 30 vaccinees were analyzed after stimulation of peripheral blood mononuclear cells (PBMCs) with 4 synthetic peptides representing the 4 T-cell epitopes of HBsAg known as of yet. The 2 epitopes P1 (aa 16-33) and P4 (aa 213-226) could be identified as the dominant ones in our vaccinees by proliferation assays and enzyme-linked immunospot assays. Responses to these epitopes were compared with responses to their naturally occurring variants found in HBV isolates of chronic virus carriers. Three of 11 variants of epitope P4 led to a complete loss of T-cell reactivity in 4 of 10 donors, all of whom reacted well to the corresponding wild-type sequence. The remaining 6 donors recognized these variants as well as the vaccine epitope. Similarly, 3 P1-variants of the 12 found induced only a significantly reduced reactivity in 4 of 10 donors, whereas they led to a normal response in the other 6 individuals. Stimulation of T cells also induced the secretion of antibody to HBsAg (anti-HBs) by specific B cells; however, those peptides that failed to activate T cells were also unable to cause any significant anti-HBs production. In conclusion, our results suggest an immune escape of certain mutant strains of HBV in vaccinated individuals could exist at the T-cell level. [source] Antituberculosis drug-related liver dysfunction in chronic hepatitis B infectionHEPATOLOGY, Issue 1 2000Wai-Man Wong Liver toxicity is a common side effect of antituberculosis (anti-TB) drugs. We studied the differences in liver dysfunction observed during anti-TB treatment between hepatitis B virus carriers (HBV) and noncarriers. Three hundred twenty-four patients on anti-TB drugs were recruited and followed up for 1 year. Forty-three patients with HBV and 276 non-HBV patients were included for analysis. Liver function tests and viral markers were monitored monthly. Liver biopsy was requested whenever the alanine transaminase (ALT) was persistently abnormal. Eighty-six HBV carriers who were not given anti-TB drugs were chosen as a second control and evaluated prospectively. The incidence of liver dysfunction was significantly higher in HBV carriers given anti-TB drugs (34.9%) when compared to noncarriers (9.4%, P < .001) and with HBV carriers not given anti-TB drugs (8.1%, P < .001). For patients given anti-TB drugs, HBV carriers who developed liver dysfunction were younger (P = .011) and had more severe liver injury compared with noncarriers (P = .008). By multiple logistic regression analysis, age (P = .002) and hepatitis B infection (P < .001) were the only 2 significant risk factors for hepatotoxicity related to anti-TB therapy. [source] Guidelines for the antiviral therapy of hepatitis C virus carriers with normal serum aminotransferase based on platelet countsHEPATOLOGY RESEARCH, Issue 1 2008Takeshi Okanoue Aim:, We aimed to identify the candidates for antiviral therapy, among patients who are hepatitis C virus (HCV) carriers with normal serum aminotransferase (ALT), focused on the inhibition of hepatocellular carcinoma (HCC). Methods:, Four hundred and sixty-four HCV carriers with normal serum ALT and 129 HCV carriers with persistently normal ALT (PNALT) and platelet (PLT) counts ,150 000/,L who received liver biopsies were enrolled. HCV carriers with normal serum ALT were divided into four groups according to their ALT levels (,30 U/L or 31,40 U/L) and PLT counts (,150 000/,L or <150 000/,L). Results:, In 129 HCV carriers with PNALT, the rate of progression of fibrosis stage was 0.05/year and no HCC was detected during the follow up for 10 years. Approximately 20% of patients with ALT ,40 U/L and PLT counts ,150 000/,Lwere at stage F2,3; however, approximately 50% of patients with ALT , 40 U/L and PLT counts <150 000/,L were at stage F2,4. An algorithm for the management of HCV carriers with normal serum ALT was advocated based on ALT and PLT counts. Conclusion:, The combination of ALT and PLT counts is useful for evaluating the fibrosis stage in HCV carriers with normal serum ALT. Most patients with PLT counts <150 000/,L are candidates for antiviral therapy, especially those with ALT levels ,31 U/L when we focus on the inhibition of the development of HCC. [source] HFE C282Y gene variant is a risk factor for the progression to decompensated liver disease in chronic viral hepatitis C subjects in the Czech populationHEPATOLOGY RESEARCH, Issue 9 2007Pácal Aim:, To determine the prevalence of selected HFE polymorphisms (C282Y, H63D and S65C) among patients with chronic viral hepatitis B and C and to investigate their role in the progression of liver disease. Methods:, A total of 207 subjects with chronic B or C viral hepatitis and 243 healthy controls were enrolled in the case,control study. Cases were further classified into three groups according to the clinical stage of liver disease: (A) virus carriers; (B) compensated liver disease; and (C) decompensated liver disease. HFE polymorphisms were detected by polymerase chain reaction-based methodology. Fisher's exact test, ,2 and Kruskal,Wallis tests were used to test for differences in variables studied between groups. Haplotypes were inferred in silico and their distribution compared by permutation test. Modified survival (time-to-event) analysis was used to test for the differences in the progression to the decompensated liver disease in carriers of C282Y wild-type versus mutated genotypes. Results:, The frequency of HFE genotypes, alleles and haplotypes differed neither between HBV nor HCV patients versus controls. In HCV subjects: (i) the frequency of the 282Y allele was significantly higher in the (C) group compared to (B) group (12.5 vs 2.2%, respectively, P = 0.002, Fisher's exact test); and (ii) carriers of the 282Y mutation exhibited significantly faster progression to decompensated liver disease than wild-type carriers (P = 0.044, log,rank test). Conclusion:, Carriage of the minor HFE C282Y polymorphism is associated with decompensated liver disease and its earlier onset in the subjects with chronic viral hepatitis C in the Czech population. [source] Patients with Epstein Barr virus-positive lymphomas have decreased CD4+ T-cell responses to the viral nuclear antigen 1INTERNATIONAL JOURNAL OF CANCER, Issue 12 2008Kevin N. Heller Abstract Epstein Barr virus (EBV) causes lymphomas in immune competent and, at increased frequencies, in immune compromised patients. In the presence of an intact immune system, EBV-associated lymphomas express in most cases only 3 or fewer EBV antigens at the protein level, always including the nuclear antigen 1 of EBV (EBNA1). EBNA1 is a prominent target for EBV-specific CD4+ T cell and humoral immune responses in healthy EBV carriers. Here we demonstrate that patients with EBV-associated lymphomas, primarily Hodgkin's lymphoma, lack detectable EBNA1-specific CD4+ T-cell responses and have slightly altered EBNA1-specific antibody titers at diagnosis. In contrast, the majority of EBV-negative lymphoma patients had detectable IFN, expression and proliferation by CD4+ T cells in response to EBNA1, and carry EBNA1-specific immunoglobulins at levels similar to healthy virus carriers. Other EBV antigens, which were not present in the tumors, were recognized in less EBV positive, than negative lymphoma patients, but detectable responses reached similar CD8+ T cell frequencies in both cohorts. Patients with EBV-positive and -negative lymphomas did not differ in T-cell responses in influenza-specific CD4+ T cell proliferation and in antibody titers against tetanus toxoid. These data suggest a selective loss of EBNA1-specific immune control in EBV-associated lymphoma patients, which should be targeted for immunotherapy of these malignancies. © 2008 Wiley-Liss, Inc. [source] Prevalence of hepatitis B virus infections in nonhuman primatesJOURNAL OF MEDICAL PRIMATOLOGY, Issue 1 2001Jens-Ove Heckel The aim of this study was to determine the prevalence of hepatitis B virus (HBV) infection in nonhuman primates. Serum samples from Europe, Thailand and Vietnam were analyzed. Sera obtained from 262 apes and 454 monkeys were tested for HBV infection serologically and for HBV DNA using nested PCR (nPCR). A total number of 198 ape sera and all but one (Cercopithecus aethiops) of the 4543 monkey sera had no serological signs of HBV infection. Among the 64 of 262 (24.4%) seropositive ape sera, we found, as in humans, different stages of HBV infection: very early HBV infection, active infection with high level of infectivity, virus carriers with low infectivity, and passed HBV infection. In the cases with passed infection, 47.8% harbored HBV DNA in the presence of protective antibodies to the HBV surface antigen (HBsAb). This indicates HBV persistence in apes despite immune control. In contrast to apes, in monkeys HBV infection is a very rare event. [source] Hepatitis C virus carriers with persistently normal ALT levels: biological peculiarities and update of the natural history of liver disease at 10 yearsJOURNAL OF VIRAL HEPATITIS, Issue 5 2006M. Persico Summary., Some chronic hepatitis C (CHC) patients exhibit persistently normal alanine aminotransferase (ALT) levels (PNAL). Patients with PNAL experience significantly milder disease. In order to understand the differences between CHC patients with elevated ALT levels compared with those with PNAL better, we compared epidemiological, immunological and histological findings, in particular, the value of proliferating hepatocyte activity (PCNA) between the two groups of patients. We studied 40 chronic hepatitis C virus (HCV) carriers with increased ALT who underwent liver biopsy for histological diagnosis and determination of clinical prognosis, and 24 PNAL patients under follow-up for 10 years. Immunological response to different HCV genomic epitopes was tested in both the control group and in PNAL subjects. PCNA values from liver specimens of all patients as well as liver biopsies of PNAL patients at time points 0 and 5 years were calculated according to Hall et al.Age, sex and body mass index (BMI) were not significantly different between the two groups. The median liver histology stage was significantly higher in HCV carriers vs the PNAL group (2.5, range = 2,6 vs 1.5, range = 1,2; P < 0.01). Among PNAL patients, histological stage was not statistically different at the three time points considered. Interferon (IFN)-gamma production was comparable in the two groups. PCNA was significantly higher in the group with elevated ALT levels vs the PNAL group (8%, range = 4,15%vs 5% range = 3,8%; P < 0.05) and no statistically significant differences were found in PNAL patients at time points 0, 5 and 10 years. This study confirms that progression to cirrhosis is slow or absent in PNAL patients after 10 years of follow-up. Accordingly, the hepatic proliferative activity index is low and seems to be stable over time. [source] | ||||||||||