ABSTRACT
O TT vírus (TTV) foi primeiramente descrito no Japão, em 1997, por T. Nishizawa, no soro de pacientes com hepatite, pós-transfusão, não-A-G. Tem sido intensivamente investigado, desde então, como uma possível adicão à lista dos vírus indutores de hepatite. O TTV é um vírus DNA não-envelopado, de fita simples. Uma considerável variabilidade genética tem sido demonstrada por parte do TTV, o que tem levado pesquisadores a agrupar isolados do vírus em inúmeros genótipos e subtipos. No entanto a significância clínica da infeccão por TTV permanece desconhecida. Ele é freqüentemente detectado em fluidos corporais e seu componente mais bem elucidado atualmente é o genoma. Conhecimentos relacionados ao TTV têm aumentado constantemente, porém vários aspectos fundamentais permanecem obscuros. Esta revisão apresenta algumas das propriedades moleculares do TT vírus.
Subject(s)
Humans , Antibodies, Viral/immunology , DNA, Viral/genetics , Genotype , Liver Diseases/virology , Torque teno virus/immunology , Torque teno virus/pathogenicity , Polymerase Chain ReactionABSTRACT
The aim of the present study was to evaluate the prevalence of HEV, TTV and GBV-C/GBV-C/HGV in patients with acute viral hepatitis A, B and non-A-C. We evaluated sera of 94 patients from a sentinel program who had acute hepatitis A (N = 40), B (N = 42) and non-A-C (N = 12); 71 blood donors served as controls. IgM and anti-HEV IgG antibodies were detected by enzyme immunoassay using commercial kits. TTV and GBV-C/HGV were detected by nested PCR; genotyping was done by sequencing and phylogenetic analysis. Anti-HEV IgG was present in 38, 10 and 17 percent of patients with hepatitis A, B and non-A-C. Four patients with hepatitis A and 1 with non-A-C hepatitis also had anti-HEV IgM detected in serum. TTV was detected in 21 percent of patients with acute hepatitis and in 31 percent of donors. GBV-C/HGV was detected in 9 percent of patients with hepatitis, and in 10 percent of donors. We found TTV isolates of genotypes 1, 2, 3, and 4 and GBV-C/HGV isolates of genotypes 1 and 2. Mean aminotransferase levels were lower in patients who were TTV or GBV-C/HGV positive. In conclusion, the detection of anti-HEV IgM in some acute hepatitis A cases suggests co-infection with HEV and hepatitis E could be the etiology of a few cases of sporadic non-A-C hepatitis in Salvador, Brazil. TTV genotype 1, 2, 3 and 4 isolates and GBV-C/HGV genotype 1 and 2 strains are frequent in the studied population. TTV and GBV-C/HGV infection does not appear to have a role in the etiology of acute hepatitis.