HBV/HCV co-infection and mixed cryoglobulinemia

It is estimated that 35-50 million people are chronically co-infected with HBV and HCV worldwide. In mono-infected patients, both viruses have been associated with numerous extrahepatic manifestations. Among these, polyarteritis nodosa and glomerulonephritis are most frequently documented in HBV and mixed cryoglobulinemia (MC) in HCV cases. With the exception of anecdotal observations, there are no data regarding MC in individuals with dual chronic infection by HCV and overt or occult HBV. Based on the interplay between the two viruses in infected patients, extrahepatic manifestations can be attributed to one or the other virus, in either a dominant or co-dominant role; however, this relationship may change over time, either spontaneously or as a consequence of therapy. Furthermore, equal or at least synergistic roles of HBV and HCV in triggering the production of cryoglobulins in some patients with overt or occult co-infection cannot be excluded. An attempt at viral eradication or sustained suppression of viral replication is indicated in all patients with cryoglobulinemic syndrome and HBV/HCV co-infection, after an accurate assessment of the activity/severity of the vasculitis and the underlying liver disease. Furthermore, due to the variable virological patterns, a careful longitudinal evaluation of the viremia levels of both HBV and HCV is mandatory prior to the initiation of antiviral therapy, in order to assess the patient's current virological status and thereby determine the most appropriate therapeutic regimen.