M. Gimenez-barcons et al., Genetic evolution of GB virus C/hepatitis G virus (GBV-C/HGV) under interferon pressure, ANTIVIR RES, 46(2), 2000, pp. 157-170
The epidemiology and clinical features of chronic GBV-C/HGV infection have
largely been explored, but there is little information about the mechanisms
enabling GBV-C/HGV to cause persistent infection. Since analysis of the ge
nomic variation of GBV-C/HGV under interferon pressure might provide some i
nsight into this issue, we analyzed the nucleotide sequence variation of th
e 5'NC and NS3 regions in GBV-C/HGV isolates obtained sequentially from sev
en patients co-infected with HCV and treated with interferon. A reduction o
f GBV-C/HGV-RNA serum level below the detection limit of the RT-PCR assay w
as observed during treatment in all patients, but upon interferon withdrawa
l, viral RNA remained undetectable in only two patients. Among the five pat
ients who did not clear GBV-C/HGV-RNA, viral strains emerging after treatme
nt were identical to those present at baseline in three cases. In a further
case, in whom GBV-C/HGV-RNA re-emerged during therapy (breakthrough episod
e), several mutations appeared in relapse samples. In the remaining patient
, with a mixed infection before therapy, only one of the two GBV-C/HGV stra
ins present at baseline was detected upon treatment withdrawal. These data
raise the possibility that positive selection may act over GBV-C/HGV genome
during interferon therapy, and contribute to persistence of infection with
this virus. (C) 2000 Elsevier Science B.V. All rights reserved.