title: Hepatitis C virus but not GB virus C/hepatitis G virus has a role in type II cryoglobulinemia.
abstract: OBJECTIVE
  Hepatitis C virus (HCV) infection is associated with type II cryoglobulinemia. HCV is specifically concentrated in type II cryoglobulins and has been implicated in the cutaneous vasculitis associated with the disease. In contrast to HCV, a role for hepatitis G virus (HGV) in type II cryoglobulinemia has not been defined, although prevalences as high as 43% of HGV infections in type II cryoglobulinemia have also been reported.
  
  
  METHODS
  We studied 34 patients with type II and 29 patients with type III cryoglobulinemia associated with HCV infection, 6 patients with essential mixed cryoglobulinemia (EMC; all with type II), 50 hospital control patients, and 125 normal individuals. Serum HCV and HGV RNA were detected by reverse transcription-polymerase chain reaction (RT-PCR). In coinfected sera, HCV and HGV were quantitated by competitive RT-PCR assays. One coinfected patient was studied longitudinally for 6 years.
  
  
  RESULTS
  Two (5.9%) of 34 patients with HCV-infected type II cryoglobulinemia, none of 29 patients with type III cryoglobulinemia, and none of 6 patients with EMC were positive for HGV RNA, for an overall prevalence of 3.0% in mixed cryoglobulinemia. None of the control populations were positive for HGV. No statistical difference was seen between the prevalence in patients with type II cryoglobulinemia and the other populations studied. In coinfected sera, HCV, but not HGV, was concentrated in cryoglobulins, and HCV, but not HGV, correlated with cryoglobulinemia in a longitudinal study.
  
  
  CONCLUSIONS
  There is a low prevalence of coinfection with HGV in patients with mixed cryoglobulinemia and HCV infection in the United States. HCV is selectively precipitated by type II cryoglobulins in coinfected sera. HGV infection does not appear to have a role in mixed cryoglobulinemia.
authors.affiliation: Lahey Clinic Medical Center, Burlington, Massachusetts 01805, USA.
authors.forename: F
authors.initials: F
authors.lastname: Liu
authors.forename: G B
authors.initials: GB
authors.lastname: Knight
authors.forename: V
authors.initials: V
authors.lastname: Agnello
mesh_terms: D000328:Adult; D003449:Cryoglobulinemia / Q000150:complications / Q000453:epidemiology / Q000821:virology*; D005260:Female; D018067:Flaviviridae / Q000502:physiology*; D016174:Hepacivirus / Q000502:physiology*; D006526:Hepatitis C / Q000150:complications / Q000453:epidemiology; D006525:Hepatitis, Viral, Human / Q000150:complications / Q000453:epidemiology; D006801:Humans; D008297:Male; D015995:Prevalence