INVESTIGADORES
BIGLIONE Mirna Marcela
congresos y reuniones científicas
Título:
IDENTIFICATION OF HDAG-L VARIANTS IN COVERT HEPATITIS D AMONG AMERINDIANS OF ARGENTINA WITH MAINLY OCCULT INFECTIONS OF HBV
Autor/es:
DELFINO C; BERINI C; EIRIN ME; RICHARD M; GENTILE E; CASTILLO A; PED; KRUPP R; OUBIÑA J; MATHET V; BIGLIONE M
Lugar:
Barcelona
Reunión:
Congreso; The Internatinal Liver Congress 2012; 2012
Resumen:
Background and
aims. HDV is a defective virus that requires the helper function of HBV for its
assembly and transmission. The HDV particle is composed of an outer envelope of
HBV surface proteins, while the genomic RNA is associated with two isoforms of
the delta antigen, HDAg-S and HDAg-L. This last plays an essential role
interacting with HBsAg in the assembly of HDV virions. Guidelines suggest that
all HBsAg-positive patients should be tested for anti-HDV IgG antibodies and
confirmed by HDV RNA detection. The aim of this study was to determine the
serological prevalence and molecular features of HDV within an Amerindian
community of Argentina. Methods.Fourty-six Mbyá-Guaranies from a community
located in the northern province of Misiones who were reactive for HBsAg and/or
total anti-HBc were tested for HDV infection. All samples were tested for total
anti-HDV by ELISA and concomitantly, a partial region coding for the HDAg was
amplified by RT-nested-PCR. The positive samples were sequenced and translated
into amino acid sequences of HDAg-S (aa110 to 198) and HDAg-L (aa 110 to 214)
by Bioedit. Results. All samples resulted non-reactive by ELISA, but 3 were
positive by RT-nPCR. These samples were anti-HBc positive only, of which 2
harbored HBV-DNA (genotypes F4 and A2), and therefore identified as cases of
occult hepatitis B infection (OBI). The 3 cases were HBeAgnegative and
presented normal ALT/AST levels, being one of them reactive for anti-HBe. All
sequences were ascribed to HDV genotype 1, but exhibited nucleotide differences
in HDAg-L among which mutations at codons 197 and 201 have been described in
vitro to promote an unsuitable interaction with HBsAg. Conclusions. These
results provide evidence of covert HDV infection even among OBI cases.
Recently, HDV infection has been described among Swiss chronic hepatitis B
patients with undetectable HBsAg. This antecedent highlights the need to
reevaluate the currently applied guidelines for HDV diagnostic algorithms; to
investigate if the presence of HDV RNA in plasma correlates with any clinical
marker of activity or stage of liver disease, as well as to explore if the
observed mutations promote any effect on in vivo HDV pathogenesis.