Hepatitis C infection is characterized by a high incidence of liver cirrhosis, frequently requiring liver transplantation. After orthotopic liver transplantation, recurrence of hepatitis C virus infection is common, but often difficult to differentiate fr

IgM antibodies to hepatitis C virus have been found in a variable proportion of patients with chronic hepatitis C. We have evaluated whether IgM anti-core antibodies correlate with viraemia or hepatic injury in chronic hepatitis C. Methods: Serum from 106 patients with chronic hepatitis C with varying stages of disease were tested for IgM anti-core hepatitis C virus by immunoassay. All patients were seropositive for IgG antibody to hepatitis C virus by second-generation ELISA; 25 had histologic cirrhosis and 57 chronic hepatitis. IgM anti-core was detected in (79.2%) patients. HCV-RNA was tested by branched (bDNA) signal amplification assay or by polymerase chain reaction in 92 patients. Results: All IgM-anti-HCV positive patients had detectable HCV-RNA. Seventy of 87 (80.5%) HCV-RNA-positive patients were IgM anti-core positive. Levels of IgM anti-HCV were significantly higher in patients with HCV-RNA detected by bDNA than in those who were bDNA negative, but there was no correlation between HCV-RNA concentrations and IgM anti-HCV levels. Of the 84 patients with positive results for IgM anti-core hepatitis C virus, 59 (70.2%) had abnormal alanine aminotransferase levels. The levels of IgM anti-core hepatitis C virus were likewise significantly higher in those with abnormal alanine aminotransferase levels. There was no difference in the percentage of patients with a positive IgM anti-HCV, or in levels of IgM anti-core hepatitis C virus in those with chronic hepatitis versus cirrhosis. Conclusions: These data suggest that the majority of patients with chronic hepatitis C virus infection are IgM anti-core hepatitis C virus positive, and the detection seems to be associated with viral replication and biochemical evidence of hepatic necrosis. IgM anti-core hepatitis testing may prove useful as an adjunct in the clinical assessment of patients with chronic hepatitis C.