title: [Hepatitis C infection with false negative serology in a patient with mixed cryoglobulinemic vasculitis].
abstract: METHODS
  A 72-year-old man with nausea, fever and elevated inflammatory parameters was transferred for further diagnostic assessment and treatment. On examination a palpable purpura was obvious without any signs of infection.
  
  
  METHODS
  Creatininekinase was 350 mmol/l with a proteinuria of 20 g per day. Histological examination revealed hypersensitivity vasculitis in the cutis and a membranoproliferative glomerulonephritis. In addition there was a mixed cryoglobulinemia with a negative test for hepatitis C virus. Further investigation revealed hepatitis C virus RNA genotype 1 b in the cryoprecipitate.
  
  
  METHODS
  The patient was successfully treated with with interferon alpha for 12 month. The nephrotic syndrome improved and the proteinuria ceased
  
  
  CONCLUSIONS
  Mixed cryoglobulinemias are associated with hepatitis C virus infection in over 80% of cases. Normally it is easy to make the diagnosis serologically with an ELISA test. But in a few cases the virus RNA is only detectable in the cryoprecipitate. If there is a high suspicion of an hepatitis C infection with cryoglobulinemia but HCV serology is negative, it is essential that virus antigen and antibodies are searched for in the cryoprecipitate.
authors.affiliation: Kantonsspital Graubünden, Medizinische Klinik.
authors.forename: G M
authors.initials: GM
authors.lastname: Tini
authors.forename: V
authors.initials: V
authors.lastname: Wüscher
authors.forename: R
authors.initials: R
authors.lastname: Jeker
mesh_terms: D000368:Aged; D000998:Antiviral Agents / Q000627:therapeutic use; D003404:Creatinine / Q000032:analysis; D003449:Cryoglobulinemia / Q000150:complications*; D005260:Female; D005838:Genotype; D015432:Glomerulonephritis, Membranoproliferative / Q000209:etiology; D016174:Hepacivirus / Q000235:genetics / Q000302:isolation & purification; D006526:Hepatitis C / Q000150:complications* / Q000175:diagnosis / Q000188:drug therapy; D006801:Humans; D016898:Interferon-alpha / Q000627:therapeutic use; D011507:Proteinuria / Q000209:etiology; D012367:RNA, Viral / Q000302:isolation & purification; D014657:Vasculitis / Q000209:etiology*
chemical_list: D000998:Antiviral Agents; D016898:Interferon-alpha; D012367:RNA, Viral; D003404:Creatinine