A New Twist to a Chronic HCV Infection: Occult Hepatitis C

Box 2

Potential pathogenic pathways to an OCI.

(I) Host defined mechanisms [16, 24, 25, 89, 98]:

   (a) a host immune response characterized by a reduced Th-1 and enhanced Th-2 response to HCV,

   (b) presence of host IL28B polymorphisms that are associated with a reduced response to IFN,

   (c) host resistance to the therapeutic actions of ribavirin,

   (d) HCV infection of B cells that manifest an interferon resistant phenotype,

   (e) enhanced frequency of posttreatment OCI in cirrhotic individuals.

(II) Viral determined mechanisms [46, 79, 94]:

   (a) viral mutations/quasispecies that enable infection of nonhepatic tissues (E2 polymorphisms and others),

   (b) presence of viral quasispecies with a reduced replicative potential that are sequestered into nonhepatic tissues

      as a means of survival in the presence of “more fit” highly replicative species.