CD81 binding regions of hepatitis C virus remain conserved after liver transplantation

CD81 is a surface-associated protein expressed in the membranes of mammalian cells. It has been suggested that CD81 interacts with hepatitis C virus E2 protein, and thus might facilitate the entry of HCV into hepatocytes. The envelope-binding site appears to involve amino acids (aa) 480-493 and 544-551 within the E2 glycoprotein. Little is known about the quasispecies genetic diversity of these two regions. We studied four patients who underwent transplantation for HCV-related cirrhosis and who developed recurrent hepatitis C. We evaluated HCV quasispecies diversity in serum samples obtained at the time of transplantation and at several time points thereafter. Quasispecies diversity was assessed by cloning and sequencing of viral isolates, with computer analysis of evolution models. The genetic distance in the region that spans aa 480 to 493 was 0.019 ñ 0.004 before the transplant, and 0.039 ñ 0.014 after the transplant (p=0.324). In the aa 544 to 551 region, the pre-transplant genetic distance was 0.012 ñ 0.008 and the post-transplant distance, 0.010 ñ 0.007 (p=0.890). There was also no significant difference between the number of nonsynonymous substitutions per nonsynonymous site before and after transplantation. In conclusion, the HCV genetic sequences of putative CD81 binding regions aa 480-493 and aa 544-551 did not diversify significantly after liver transplantation. This may favor HCV re-infection of the allograft after liver transplantation.

Seroprevalence and risk factors associated with Helicobacter pylori infection in blood donors in Salvador, Northeast-Brazil

Helicobacter pylori plays an important role in the etiology of peptic ulcer disease. Its prevalence appears to be higher in developing countries. We evaluated the seroprevalence of H. pylori and risk factors associated with infection in voluntary blood donors who attended the main blood center of the city of Salvador, Brazil. The subjects responded to an epidemiological questionnaire, with information about sex, age, race, lifestyle, social-economic level indicators, and residence and hygiene conditions. Anti-H. pylori antibody was determined by ELISA (Cobas Core, Roche). Three hundred and seven subjects were included in the study. Anti-H. pylori antibody results were indeterminate in 33 individuals (10.8 percent), who were excluded from analysis. Among the remaining 274 subjects, 187 (68.2 percent) were anti-H. pylori positive. Based on multivariate logistic regression analysis three variables were found to be significantly associated with a higher prevalence of H. pylori infection: absence of plumbing in the residence during childhood, a history of rainwater invading the dwelling during childhood, and low ingestion of milk.

Prevalence of TTV in blood donors and patients with acute viral hepatitis and genotyping by phylogenetic analysis

O objetivo desse estudo foi avaliar a prevalência da infecção pelo TTV em pacientes com hepatite aguda A e B e genotipar os isolados do TTV através de análise filogenética. Foram avaliados soros de 82 pacientes que apresentaram hepatite aguda A(N = 40) e B (N = 42)e 71 doadores de sangue. O TTV foi determinado atraváes nested-PCR, e a análise filogenetica foi realizada utilizando o metódo neighbor-Joining". O TTV foi detectado em 23por cento dos pacientes com hepatite aguda e em 31 por cento dos doadores. Os níveis médiosde aminotransferases foram semelhantes em pacientes TTV positivos e pacientes TTV negativos. Uma árvore filogenética foi construída e mostrou isolados do TTV dos genótipos1,2,3 e 4. Em conclusão, a infecção pelo TTV foi mais frequente entre doadores de sangue do que em pacientes com hepatite aguda A ou B, em Salvdor-Bahia. O TTV não aumentou a gravidade da atividade necroinflamatória dos pacientes com hepatite aguda A ou B. Através de análise filogenétiaca foram encontrados isolados do TTV dos genótipos 1,2,3 e 4 na população estudada