宫颈癌患者人乳头瘤病毒感染分布特点

目的:探讨人乳头瘤病毒(HPV)各亚型在广西沿海地区宫颈癌患者中的分布情况,HPV感染与宫颈癌患者的年龄、临床分期、病理类型、分化程度、肿瘤盆腔淋巴结转移及肿瘤的复发的关系。方法:通过凯普导流杂交HPV DNA检测法,对76例宫颈癌患者宫颈脱落细胞进行21种HPV亚型的检测。结果:宫颈癌HPV总阳性率为90.8%。宫颈癌患者HPV阳性各亚型出现的频率排序为:HPV16(56.5%),HPV18、33、58各(7.2%),HPV52、53各(5.8%),HPV31(4.3%),HPV45(2.9%),HPV35、51、56、66、68各(1.4%)。HPV6(5.8%),HPV11、44、43各(1.4%)均合并在高危感染中。HPV感染与临床分期、肿瘤分化程度、肿瘤盆腔淋巴结转移及肿瘤的复发关联无显著性(P>0.05),与年龄密切相关,鳞癌HPV阳性率明显高于腺癌及其它癌,差异有统计学意义(P<0.05)。结论:广西沿海地区妇女宫颈癌患者中以HPV16、18、33、58感染为主要型别。HPV感染与宫颈癌的临床分期、肿瘤分化程度、肿瘤盆腔淋巴结转移及肿瘤的复发无明显相关性,与发病年龄、病理类型有关。     

IL28B polymorphisms predict response to therapy among chronic hepatitis C patients with HCV genotype 4

Summary. Genetic polymorphisms near IL28B are associated with spontaneous and treatment‐induced clearance of hepatitis C virus (HCV). Our objective was to assess the predictive value of IL28B polymorphisms in the treatment of chronic hepatitis C of patients with HCV genotypes 4, for which data are currently limited. We analysed the association of IL28B polymorphisms with the virological response to treatment among 182 naïve chronic hepatitis C patients with HCV genotype 4, all from Syria. Associations of alleles with the response patterns were evaluated by univariate analysis and multivariate logistic regression, accounting for all relevant covariates. Sustained virological response (SVR) was achieved in 26% of rs8099917 TG/GG carriers compared with 60% of TT carriers (P < 0.0001) and 35% of rs12979860 CT/TT carriers compared with 62% of CC carriers (P = 0.0011). By multivariate analysis, the association between rs8099917 and SVR remained significant (OR = 0.19, 95% CI 0.07–0.50, for TG/GG vs TT, P = 0.0007), with the only significant covariate being advanced fibrosis (OR = 0.13, 95% CI 0.04–0.37, P = 0.0002). In conclusion, IL28B polymorphisms are the strongest predictors of response to therapy among chronic hepatitis C patients with HCV genotype 4.     

Different immunogenicity of H-2 Kb-restricted epitopes in natural variants of the hepatitis B surface antigen

The small hepatitis B surface antigen (HBsAg) of hepatitis B virus (HBV) has limited variability, but some serotypes and genotypes have been defined. Although no biological or pathogenetic differences could be traced to HBV serotypes, the clinical picture, response to treatment and long-term prognosis of HBV infection may vary with the HBV genotype, possibly due to differences in specific T cell recognition of HBV antigens from different genotypes. We analyzed murine CD8(+) T cell responses to two K(b)-restricted HBsAg epitopes primed by four different HBsAg variants using protein- and DNA-based vaccination protocols. The K(b)-binding S(208-215) epitope 1 is processed from exogenous but not endogenous HBsAg. Variants of epitope 1 differing at two positions within the epitope (ILSPFLPL in ayw/adr versus IVSPFIPL in adw2) efficiently primed cross-reactive CD8(+) T cell responses. In contrast, the exchange of an N-terminal flanking residue (S to N) completely eliminated the immunogenicity of epitope 1. The K(b)-binding S(190-197) epitope 2 is processed from endogenous but not exogenous HBsAg. A single-residue exchange within the epitope (VWLSVIWM in ayw/adr versus VWLSAIWM in adw2) completely eliminated the immunogenicity of epitope 2. Single, conservative residue exchanges can thus give rise to diverging CD8(+) T cell repertoires, suggesting an impressive complexity and flexibility of the CD8(+) T cell repertoire to antigen variants from viruses with limited diversity.     

Prognostic importance of DNA repair gene polymorphisms of <Emphasis Type="Italic">XRCC1</Emphasis> Arg399Gln and <Emphasis Type="Italic">XPD</Emphasis> Lys751Gln in lung cancer patients from India

Purpose Inter individual variation in lung cancer susceptibility may be modulated in part through genetic polymorphisms in the DNA repair genes, especially the genes involved in the Base Excision Repair (BER) and nucleotide excision repair (NER) pathway. Two of the genetic polymorphisms, XRCC1Arg399Gln and XPD Lys751Gln have been extensively studied in the association with lung cancer risk, although published studies have been inconclusive. Methods In order to verify the role of the common variant alleles in the XPD gene, we have genotyped 211 lung cancer patients and 211 healthy controls using PCR-RFLP assays in a hospital based, case-control study in an Indian population. Logistic regression models were fit to examine the relationship between the log odds of lung cancer and each covariate. Overall Survival in relation to various genotypes and clinicopathological factors were analyzed using Kaplan Meier estimates and hazard ratios were calculated using Cox Regression analysis. Results The carriers of XRCC1 399 AA genotypes were at higher risk of lung cancer (OR = 2.1, 95% CI:1.224–3.669, P = 0.007) than carriers of GG genotype. Subjects carrying 751 AC genotype were at an increased risk of carcinoma of the lung (OR = 1.8; 95% CI:1.233–2.807, P = 0.003) than subjects with AA genotypes. Compared to the XRCC1 399 GG/ XPD 751 AA reference genotype, the combined variants, XRCC1 399 GG/ XPD 751 AC+CC (OR = 1.9, 95% CI: 1.037–3.481), P = 0.03), XRCC1 399 GA+AA/ XPD 751 AA (OR = 1.7, 95% CI: 1.020–2.833, P = 0.04), XRCC1 399 GA+AA/XPD 751 AC+CC (OR = 2.7, 95% CI: 1.582–4.864, P = 0.01), had significantly higher odds ratios. Increasing numbers of either XPD or XRCC1 variant alleles were associated with shorter overall survival, the risk being significant for the XRCC1 gene polymorphism (P = 0.01 by log-rank test). The hazard of dying was significant for the XRCC1 399 AA genotype (HR = 3.04, 95%CI: 1.393–6.670, P = 0.005). Higher tumour stage also came out as significant predictors of patient death. Conclusions These findings suggest that genetic polymorphisms in the DNA repair genes may modulate overall lung cancer susceptibility and that pathological stage and XRCC1 Arg399Gln independently predicted overall survival among Indian lung cancer patients.     

Contrasting patterns of hepatitis C virus infection in two regions from Tunisia

This report is a population-based study describing the pattern of hepatitis C virus (HCV) infection in two distinct regions in Tunisia. The study included a total of 11,507 individuals sampled in 1996 from both genders, all age groups, urban and rural settings belonging to 2,973 families. HCV infection was assessed by commercial enzyme immunoassay (EIA) and immunoblot assays and detection of HCV RNA by PCR. HCV genotypes and subtypes were determined by sequencing in the 5'-untranslated region (UTR) viral genomic region and the INNO-LiPA HCVII genotyping kit. Genetic relatedness between HCV strains was assessed by sequencing of a portion of the NS5B region. HCV prevalence was significantly higher in the North-Western region than in the Southern one: 1.7% versus 0.2% (P < 10(-3), chi(2) = 8,506). There was no difference in positivity according to gender or living in rural or urban settings; the only significant risk factor was advanced age. HCV prevalence among household contacts of HCV positives was not significantly higher than the prevalence in the whole study population. These results indicate a heterogeneity in the geographical distribution of HCV in Tunisia. An increased HCV transmission occurs in the North-Western region with large predominance of genotype 1b (88%) and low contribution of intrafamilial transmission.     

Prevalence and genotypic distribution of TT virus in Athens, Greece

The prevalence of TT virus (TTV) infection in various population groups from Athens, Greece, was assessed by the polymerase chain reaction (PCR) using two primer sets from distinct regions of the genome: the conventional set derived from the open reading frame-1 (ORF-1) and the new, highly sensitive set targeting the region that includes the TATA signal localized upstream of ORF-2. Based on both primer sets, TTV DNA was detected in 42/50 (84.0%) healthy individuals, 42/50 (84.0%) chronic hepatitis C patients, 31/39 (79.5%) acute non-A-E hepatitis patients (group I), 14/16 (87.5%) renal failure patients with acute non-A-E hepatitis (group II), 47/50 (94.0%) intravenous drug users (IVDU), 36/50 (72.0%) hemophiliacs, and 21/31 (67.7%) hemodialysis patients. The presence of TTV was not associated with any particular risk group, and no differences were observed in relation to demographic, biochemical and virological characteristics between TTV DNA-positive and -negative patients. TTV did not seem to have a profound effect on the course of chronic C or acute non-A-E hepatitis either. Phylogenetic analysis revealed that TTV strains circulating in the greater metropolitan area of Athens belong not only to the G1 and G2 genotypes that are encountered worldwide, but also to G3 and to G5 that are found mainly in Europe and Asia, respectively. Further studies will shed light on the role of this highly prevalent virus.     

Epidemiology,Molecular Epidemiology and Evolution of Bovine Respiratory Syncytial Virus

The bovine respiratory syncytial virus (BRSV) is an enveloped, negative sense, single-stranded RNA virus belonging to the pneumovirus genus within the family Paramyxoviridae. BRSV has been recognized as a major cause of respiratory disease in young calves since the early 1970s. The analysis of BRSV infection was originally hampered by its characteristic lability and poor growth in vitro. However, the advent of numerous immunological and molecular methods has facilitated the study of BRSV enormously. The knowledge gained from these studies has also provided the opportunity to develop safe, stable, attenuated virus vaccine candidates. Nonetheless, many aspects of the epidemiology, molecular epidemiology and evolution of the virus are still not fully understood. The natural course of infection is rather complex and further complicates diagnosis, treatment and the implementation of preventive measures aimed to control the disease. Therefore, understanding the mechanisms by which BRSV is able to establish infection is needed to prevent viral and disease spread. This review discusses important information regarding the epidemiology and molecular epidemiology of BRSV worldwide, and it highlights the importance of viral evolution in virus transmission.     

Dynamic colonisation by different Pneumocystis jirovecii genotypes in cystic fibrosis patients

Although asymptomatic carriers of Pneumocystis jirovecii with cystic fibrosis (CF) have been described previously, the molecular epidemiology of P. jirovecii in CF patients has not yet been clarified. This study identified the distribution and dynamic evolution of P. jirovecii genotypes based on the mitochondrial large-subunit (mt LSU) rRNA gene. The mt LSU rRNA genotypes of P. jirovecii isolates in 33 respiratory samples from CF patients were investigated using nested PCR and direct sequencing. Three different genotypes were detected: 36.3% genotype 1 (85C/248C); 15.1% genotype 2 (85A/248C); 42.4% genotype 3 (85T/248C); and 6% mixed genotypes. Patients studied during a 1-year follow-up period showed a continuous colonisation/clearance cycle involving P. jirovecii and an accumulative tendency to be colonised with genotype 3.