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Viral Factors (viral + factor)
Selected AbstractsClose association of CD8+/CD38bright with HIV-1 replication and complex relationship with CD4+ T-cell count,CYTOMETRY, Issue 4 2009Edouard Tuaillon Abstract Background: Measuring lymphocyte activation provides information in addition to CD4+ T-cell count for immune monitoring of HIV-1 infected patients. CD38 is a well-established activation marker that is generally analyzed on the whole population of CD8+ T-cells. Focusing specifically on CD38 high expression (CD8+/CD38bright) may be an interesting surrogate gating strategy because CD38bright characterizes principally activated memory cells. Methods: CD8+/CD38bright was investigated in 1,353 HIV-1 infected patients over a one-year period to establish relevant cutoff values and clarify the relationships of this marker with HIV-1 RNA viral load (VL) and CD4+ T-cell count. Results: The CD8+/CD38bright (>8,500 CD38 binding site per cells) is well correlated with HIV-1 VL (r = 0.87, P < 0.001) in this longitudinal follow-up of nonimmunodepressed patients that initiated antiviral therapy (ART). In aviremic patients on ART, the marker was highly predictive of VL rebound (sensitivity 93%, specificity 64% for a VL level of detection >200 copies/ml). While the CD8+/CD38bright moderately correlated with CD4+ T-cell count independently of the VL (r = ,0.37, P < 0.001), it increased dramatically in aviremic patient groups that exhibited profound CD4+ T-cell depletion (median 39% for CD4+ T-cell counts <50/mm3). This result indicates that other additional immunological and/or viral factors than readily detectable HIV-1 replication appears to be involved in T-cell activation of immunodepressed individuals. Conclusions: CD8+/CD38bright is an effective marker for monitoring T-cell activation, which is a central factor of HIV-1 pathogenesis. This gating strategy requires only a single additional staining in conventional four color CD4 protocols. © 2008 Clinical Cytometry Society [source] Influence of genotypes and precore mutations on fulminant or chronic outcome of acute hepatitis B virus infection,,HEPATOLOGY, Issue 2 2006Atsushi Ozasa The outcome of acute hepatitis B virus (HBV) infection is variable, influenced by host and viral factors. From 1982 through 2004, 301 patients with acute HBV infection entered a multi-center cross-sectional study in Japan. Patients with fulminant hepatitis (n = 40) were older (44.7 ± 16.3 vs. 36.0 ± 14.3 years, P < .0017), less predominantly male (43% vs. 71%, P = .0005), less positive for hepatitis B e antigen (HBeAg) (23% vs. 60%, P < .0001), less infected with subgenotype Ae (0% vs. 13%, P < .05), and more frequently with Bj (30% vs. 4%, P < .0001) than those with acute self-limited hepatitis (n = 261). Precore (G1896A) and core-promoter (A1762T/G1764A) mutations were more frequent in patients with fulminant than acute self-limited hepatitis (53% vs. 9% and 50% vs. 17%, P < .0001 for both). HBV infection persisted in only three (1%) patients, and they represented 2 of the 23 infected with Ae and 1 of the 187 with the other subgenotypes (9% vs. 0.5%, P = .032); none of them received antiviral therapy. In multivariate analysis, age 34 years or older, Bj, HBeAg-negative, total bilirubin 10.0 mg/dL or greater, and G1896A mutation were independently associated with the fulminant outcome. In in vitro transfection experiments, the replication of Bj clone was markedly enhanced by introducing either G1896A or A1762T/G1764A mutation. In conclusion, persistence of HBV was rare (1%) and associated with Ae, whereas fulminant hepatitis was frequent (13%) and associated with Bj and lack of HBeAg as well as high replication due to precore mutation in patients with acute HBV infection. (HEPATOLOGY 2006;44:326,334.) [source] The importance of steatosis in chronic hepatitis C infection and its management: A reviewHEPATOLOGY RESEARCH, Issue 3 2010Timothy J. S. Cross Hepatitis C virus (HCV) infection is a major cause of chronic liver disease with approximately 180 million people infected worldwide. Hepatic steatosis is a frequent histological finding in chronic hepatitis C (CHC) infection and is 2- to 3-fold more common than would be expected by chance alone. A high body mass index with excess visceral fat distribution is associated with steatosis in patients infected with HCV genotype 1 but not genotype 3, re-enforcing the concept that in patients with CHC, some have "metabolic steatosis", predominantly HCV genotype 1, and others "viral steatosis", mainly HCV genotype 3. Accumulating evidence suggests that steatosis may contribute to progression of fibrosis in CHC. Hepatic insulin resistance appears to play a role through the pro-fibrogenic effects of compensatory hyperinsulinemia. The aim of this review was to assess the effect host and viral factors play in steatosis development in patients with CHC infection and its possible relationship with hepatocellular carcinoma. The review examines the mechanisms by which CHC infection causes hepatic steatosis, the impact hepatic steatosis has on the natural history of the disease and finally, explores if treatments leading to a reduction in the amount of steatosis might lead to improved treatment outcomes. The basic medical science of steatosis in CHC will be discussed including proposed models of steatogenesis and the influence of viral and metabolic factors at the molecular level and how these might impact on current and future therapies. [source] Interaction of host and viral risk factors for development of cervical carcinoma in situINTERNATIONAL JOURNAL OF CANCER, Issue 4 2005Anna H. Beskow Abstract Infection by oncogenic human papillomavirus (HPV) is a necessary but not sufficient cause of cervical carcinoma. Several host genetic and viral factors have been reported to increase the risk of carcinoma development given an HPV infection. In our study, we have analysed the contribution of HPV 16 E6 sequence subtype and allelic variation at human leukocyte antigen (HLA) class II loci to the risk of developing cervical carcinoma in situ. Non-European-like HPV 16 E6 sequence subtypes were not found to be associated with an increased risk of cervical carcinoma, as compared to European-like variants. However, an association was found between the HPV 16 E6 L83V variant and the DR*04-DQ*03 haplotype. This association has been observed in several independent studies and shows that both the host HLA class II genotype and viral subtype will affect the risk of an infection progressing into cervical carcinoma. © 2005 Wiley-Liss, Inc. [source] Dendritic cells in viral pathogenesis: protective or defective?INTERNATIONAL JOURNAL OF EXPERIMENTAL PATHOLOGY, Issue 4 2005Gabriele Pollara Summary Dendritic cells (DC) are potent antigen-presenting cells that are critical in the initiation of immune responses to control and/or eliminate viral infections. Recent studies have investigated the effects of virus infection on the biology of DC. This review summarizes these changes, focusing on both the DC parameters affected and the viral factors involved. In addition, the central role of DC biology in the pathogenesis of several viral families, including herpesviruses, paramyxoviruses and retroviruses, is explored. The field of pathogen recognition by DC is addressed, focusing on its role in protecting the host from viral infection, as well as the ability of viruses to exploit such host receptor ligation and signalling to their replicative advantage. The hypothesis is proposed that virus and host have evolved a symbiotic relationship to ensure both viral transmission and host survival. [source] Hepatic steatosis in chronic hepatitis B patients is associated with metabolic factors more than viral factorsJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 7pt1 2008Dandan Peng Abstract Background and Aims:, Hepatic steatosis is commonly seen in chronic hepatitis C (CHC) patients. It has been reported to be associated with both metabolic factors and viral factors, and affects the severity of fibrosis in CHC. However, the relationship between hepatic steatosis and chronic hepatitis B (CHB) is unclear. The aims of this study were to investigate the frequency of hepatic steatosis in CHB patients, to identify the factors associated with its presence, and assess the relationship between the stage of steatosis and the severity of fibrosis. Methods:, Medical records of 153 adult patients with CHB who had undergone a liver biopsy within the past 4 years were included in the study. Results:, Body mass index (BMI) and age of CHB patients with steatosis was significantly higher than the patients without steatosis (P < 0.05), as determined by the univariate analysis. Steatosis was found to correlate with the BMI values and alanine aminotransferase (ALT) levels, and ALT levels were associated with hepatitis B virus (HBV),DNA levels and histology activity index (HAI) scores, stages of fibrosis were associated with the HAI score and HBV,DNA, as determined by the multivariate analysis. In contrast, there was no significant association between advanced stages of fibrosis and steatosis. Conclusion:, Our data indicate that hepatic steatosis is more frequently present in CHB patients than in the general population. We hypothesize that steatosis in CHB patients may be due to metabolic factors and the ability of HBV to indirectly facilitate the development of steatosis. In the present study, steatosis in CHB patients was not found to be associated with the severity of fibrosis. [source] Genotype-specific mechanisms for hepatic steatosis in chronic hepatitis C infectionJOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 8 2002Jason M Hui Abstract Background: Hepatic steatosis is common in hepatitis C, but the relative importance of host and viral factors is controversial. In the present prospective study, we examined metabolic factors associated with non-alcoholic fatty liver and viral genotype as predictors of steatosis and fibrosis in chronic hepatitis C infection. Methods: In 124 chronic hepatitis C patients, the association between liver histology and the following was investigated: demographic and anthropometric data, alcohol intake, alanine aminotransferase (ALT), total cholesterol, low-density lipoprotein,cholesterol, high-density lipoprotein,cholesterol, triglyceride, transferrin saturation, ferritin, insulin, c-peptide, glucose and insulin resistance (homeostasis model). Results: By multivariate analysis, genotype 3 was associated with increased steatosis grade (P = 0.02). There were significant pairwise interactions between genotype 3 status and total cholesterol (P = 0.01), current alcohol intake (P = 0.04) and serum ALT (P = 0.01). This showed that the etiology of steatosis was different in patients with genotype 3 and those with non-genotype 3 chronic hepatitis C infection. In genotype 3 patients, the degree of steatosis was inversely associated with serum cholesterol (P = 0.005) and positively associated with serum triglyceride (P = 0.02). There was no association between body mass index (BMI) and the extent of steatosis. Among patients with other genotypes, the steatosis grade was strongly influenced by BMI (P < 0.0001) and serum ALT (P < 0.01). Independent predictors of fibrosis were age (P = 0.001), past alcohol intake (P = 0.04), ALT (P = 0.002), serum insulin (P = 0.001) and portal inflammation (P < 0.001). Conclusions: Hepatitis C genotype 3 may interfere with pathways of hepatic lipid metabolism, whereas increased BMI appears to be a more important pathogenic factor in other genotypes. Although steatosis and BMI were not associated with hepatic fibrosis, their relationship with serum insulin suggests that metabolic factors related to insulin action could influence fibrogenesis in hepatitis C. [source] Predictors of the efficacy of interferon therapy for patients with chronic hepatitis C before and during therapy: how does this modify the treatment course?JOURNAL OF GASTROENTEROLOGY AND HEPATOLOGY, Issue 2000Yasushi Shiratori Antiviral therapy for hepatitis C virus (HCV) infection should be based on the natural history of HCV infection; there is a sequential, but slow, progression from chronic hepatitis to cirrhosis, leading to death from either liver failure or hepatocellular carcinoma (HCC). The risk of HCC development increases in association with the advance of fibrosis, and antiviral therapy can reduce this risk. More than 30 indices have been proposed as ,predictors' of favourable response to IFN therapy: host factors (age, gender, duration of HCV-infection, alcohol intake, hepatic iron stores, platelet count, histological staging of the liver disease), viral factors (HCV RNA levels in serum, HCV subtype, diversity of the hypervariable region, mutation of non-structure 5A gene), and IFN factors (dose, duration of treatment, type, treatment regimens i.e. every day vs three times a week, escalating dose regimen). Before starting IFN therapy, HCV subtype and pretreatment HCV RNA load, as well as the fibrotic stage of the liver, should be determined. The response to IFN therapy should be monitored by the HCV RNA status in serum during therapy, and the treatment regimen modified, or discontinued as required. A sustained virological response should be checked at more than 3 months after the completion of therapy. Even though the risk of HCC is markedly reduced in sustained responders, it is possible to develop HCC several years after completion of IFN therapy. [source] Evaluation of host genetic and viral factors as surrogate markers for HTLV-1-associated myelopathy/tropical spastic paraparesis in Peruvian HTLV-1-infected patientsJOURNAL OF MEDICAL VIROLOGY, Issue 3 2010Michael Talledo Abstract Human T-lymphotropic virus 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a complication that affects up to 5% of HTLV-1-infected individuals. Several host genetic and viral factors have been associated with the risk of HAM/TSP. The aim of this study was to evaluate the performance of a prognostic model for HAM/TSP developed in Japan in a Peruvian population of 71 HAM/TSP patients and 94 asymptomatic carriers (ACs). This model included age, proviral load (PVL), the presence of HLA-A*02 and HLA-Cw*08 alleles, SDF-1 +801, and TNF -, ,863 polymorphisms, and viral subgroup. We describe frequencies for the four host genetic markers and demonstrate the presence of the HTLV-1 tax B subgroup in Peru. Using cross-validation, we show that the predictive ability of the prognostic model, as characterized by the area under the receiver-operating characteristic curve (AUC), does not differ from a model containing PVL only (both AUC,=,0.74). We found some suggestive evidence of a protective effect of the HLA-A*02 allele but failed to replicate the associations with the other three genetic markers and with viral subgroup. A logistic model containing PVL, age, gender, and HLA-A*02 provided the best predictive ability in the Peruvian cohort (AUC,=,0.79). J. Med. Virol. 82:460,466, 2010. © 2010 Wiley-Liss, Inc. [source] Do human polyoma viruses and human immunodeficiency virus share common co-receptors?JOURNAL OF MEDICAL VIROLOGY, Issue 1 2010Kalin Borissov Abstract Host and/or viral factors involved in human polyomavirus (HPoV) infection in persons living with HIV remain unknown. A hypothesis is outlined suggesting the importance of the co-receptors CCR5, CCR2, and CXCR4 not only for HIV, but also for HPoV. Functionally capable receptors coded by wild-type (wt) genotypes could facilitate internalization of HPoV in the cell resulting in brain and/or kidney infection/s in HIV infected individuals. Forty-nine Bulgarians with HIV, all treated by HAART, without neurological and/or kidney disorders, were tested for JCV and BKV and genotyped for CCR5 (CCR5del32), CCR2 (CCR2-64I), and CXCR4 (SDF1-3,A). In 27/49 (55.1%) individuals a co-infection with HPoV was identified,BKV in 12/49 (24.5%), JCV,in another 12/49 (24.5%), and both viruses,in 3/49 (6.1%). A high frequency of wt CCR5 was found in patients with HPoV (91.7% for BKV and JCV and in 100% with both viruses). V/V of CCR2 was presented in 75% for BKV and JCV and in 66.7% for BKV plus JCV. SDF1-3,G/G predominated in JCV infected patients (75%), while G/A and A/A genotypes were more frequent in patients with BKV (41.7%). Also, 21/22 (95.4%) persons without HPoV infection were heterozygous for SDF1 and CCR2. The number of individuals bearing wt of all co-receptors in the group of persons not infected with HPoV was lower (P,=,0.03) than that with polymorphism/s in one or two genes (SDF1 and CCR2) in the same group. The results suggest a probable role of co-receptors used by HIV to facilitate infection with HPoV. J. Med. Virol. 82:8,13, 2010. © 2009 Wiley-Liss, Inc. [source] Association of viral factors with non-familial breast cancer in Taiwan by comparison with non-cancerous, fibroadenoma, and thyroid tumor tissues,JOURNAL OF MEDICAL VIROLOGY, Issue 2 2005Ju-Hsin Tsai Abstract To study the etiologic factors of non-familial breast cancer, the polymerase chain reaction (PCR) and Southern hybridization were used to detect six viruses including human papillomavirus (HPV), cytomegalovirus (CMV), Epstein,Barr virus (EBV), herpes simplex virus (HSV)-1, HSV-2, and human herpesvirus (HHV)-8 DNA in 69 patients with breast cancer and 60 specimens from non-cancerous or other individuals with thyroid tumors or fibroadenoma (non-breast cancer controls). Two specimens from patients with a familial history of breast cancer and five breast cancer specimens with negative results for ,-globin, which was used as internal control, were excluded from this study. Eight (12.9%) HSV-1, 28 (45.2%) EBV, 47 (75.8%) CMV, 8 (12.9%) HPV, and 28 (45.2%) HHV-8 positive samples out of the 62 breast cancer specimens were detected; no HSV-2 DNA was detected in any group. Among the viral gene-positive breast cancer samples, 12 (23.1%) were positive for 1 virus, 16 (30.8%) were positive for 2 viruses, 21 (40.4%) were positive for 3 viruses, and 3 (5.8%) were positive for 4 viruses. Among the viral gene-positive specimens of the control groups, only one virus, CMV, was found in the non-cancerous and thyroid tumor specimens, while multiple viruses were found in the fibroadenoma specimens. The viruses associated with breast cancer were HHV-8,>,EBV (P,<,0.01). The viruses associated with fibroadenoma were HSV-1 and HHV-8,>,EBV (P,<,0.01). The presence of more than one virus was found predominantly in breast cancer and exclusively found in fibroadenoma. CMV was the only virus associated with thyroid tumors. J. Med. Virol. 75:276,281, 2005. © 2004 Wiley-Liss, Inc. [source] Association of genetic polymorphisms with interferon-induced haematologic adverse effects in chronic hepatitis C patientsJOURNAL OF VIRAL HEPATITIS, Issue 6 2009M. Wada Summary., Interferon (IFN)-based combination therapy with ribavirin has become the gold standard for the treatment of chronic hepatitis C virus infection. Haematologic toxicities, such as neutropenia, thrombocytopenia, and anaemia, however, frequently cause poor treatment tolerance, resulting in poor therapeutic efficacy. The aim of this study was to identify host genetic polymorphisms associated with the efficacy or haematologic toxicity of IFN-based combination therapy in chronic hepatitis C patients. We performed comprehensive single nucleotide polymorphism detection in all exonic regions of the 12 genes involved in the IFN signalling pathway in 32 healthy Japanese volunteers. Of 167 identified polymorphisms, 35 were genotyped and tested for an association with the efficacy or toxicity of IFN plus ribavirin therapy in 240 chronic hepatitis C patients. Multiple logistic regression analysis revealed that low viral load, viral genotypes 2 and 3, and a lower degree of liver fibrosis, but none of the genetic polymorphisms, were significantly associated with a sustained virologic response. In contrast to efficacy, multiple linear regression analyses demonstrated that two polymorphisms (IFNAR1 10848-A/G and STAT2 4757-G/T) were significantly associated with IFN-induced neutropenia (P = 0.013 and P = 0.011, respectively). Thrombocytopenia was associated with the IRF7 789-G/A (P = 0.031). In conclusion, genetic polymorphisms in IFN signalling pathway-related genes were associated with IFN-induced neutropenia and thrombocytopenia in chronic hepatitis C patients. In contrast to toxicity, the efficacy of IFN-based therapy was largely dependent on viral factors and degree of liver fibrosis. [source] Lower serum viral loads in young patients with hepatitis-B-virus-related hepatocellular carcinomaJOURNAL OF VIRAL HEPATITIS, Issue 3 2007F.-C. Tsai Summary., Advanced age and high hepatitis B virus (HBV) DNA level are risk factors associated with the development of HBV-related hepatocellular carcinoma (HCC). However, little is known about the role of viral load in the carcinogenesis of HCC in young people. A total of 183 HBV-related HCC patients and 202 HBV carriers were therefore enrolled to compare serum viral loads in young (,40 years of age) and old (>40 years of age) age groups. Other factors associated with the development of HCC were also analysed. The results showed that serum alanine aminotransferase (38.7 ± 24.1 vs 58.4 ± 65.4 IU/L, P = 0.006) and HBV DNA levels (log10 titre: 4.20 ± 1.33 vs 4.80 ± 1.39, P = 0.053) were lower in young HCC patients than in old HCC patients. There was a positive correlation between age and serum HBV DNA level in HCC patients but a negative correlation in HBV carriers. Young HCC patients with HBV genotype B infection had higher viral loads than those with genotype C infection (log10 titre: 4.79 ± 1.34 vs 3.27 ± 0.60, P = 0.001). By multivariate logistic regression analyses, high serum HBV DNA level was associated with the development of HCC in old patients [odds ratio (OR) 1.584, 95% confidence interval (CI) 1.075,2.333] rather than in young patients (OR 0.848, 95% CI 0.645,1.116). In conclusion, viral factors in association with the development of HBV-related HCC in young patients may be different from their old counterparts. The complicated interplay between host and virus could be responsible for the emergence and aggressive outcome of early-onset HCC. [source] The etiology of otosclerosis: A combination of genes and environment,THE LARYNGOSCOPE, Issue 6 2010Isabelle Schrauwen MSc Abstract Otosclerosis is a common form of hearing loss characterized by abnormal bone remodeling in the otic capsule. It is a complex genetic disease, caused by a combination of genetic and environmental factors. During the past decade, several attempts have been made to identify factors for otosclerosis. This review provides an overview of the current understanding of the etiology of otosclerosis and describes the genetic and environmental factors that have been implicated in the disease. Environmental factors include fluoride and viral factors, particularly measles. Genetic association studies for otosclerosis have reported several associations of genetic variants that influence the risk of disease, mainly involving bone remodeling pathways, although their individual risk contributions are small. Rare monogenic forms of otosclerosis also exist, which are caused by a mutation in a single gene leading to a clear familial segregation of the disease. Linkage analysis of large otosclerosis families has led to the identification of seven loci, and recently evidence was found that T cell receptor beta is a gene responsible for familial otosclerosis, suggesting an underlying immunological pathway. However, this might also represent an autoimmune process, a hypothesis that is supported by other data as well. In conclusion, a variety of pathways have been identified to be involved in the development of otosclerosis, showing that distinct mechanisms involving both genetic and environmental risk factors can influence and contribute to a similar disease outcome. [source] | |||||||||||||||||||||||||