IGM ANTIBODY TO A HEPATITIS-C VIRUS CORE PEPTIDE (CP14) FOR MONITORING ACTIVITY OF LIVER-DISEASE IN PATIENTS WITH ACUTE OR CHRONIC HEPATITIS-C

Antibodies to the hepatitis C virus (HCV) core of various immunoglobulin classes were determined by enzyme immunoassays with three synthetic peptides, CP14 (amino acids 5-40 of the core protein), CP10 (5-23), and CP9 (39-74). in 735 patients with chronic type C liver disease, anti-CP14, anti-CP10, and anti-CPS of IgG class were detected in 99%, 94%, 82%, respectively; those of IgM class in 86%, 69%, and 39%; and those of IgA class in 56%, 40%, and 4%. Thus anti-CP14 was more prevalent than anti-CP10 or anti-CPS in every immunoglobulin class. The prevalence of IgM anti-CP14 was much higher (P < 0.001) in patients (116/135 or 86%) than in asymptomatic carriers of HCV (13/39 or 33%). In seven patients with acute hepatitis C, IgM anti-CP14 continued to decrease in two in whom hepatitis resolved, but increased in five in whom hepatitis once resolved and then exacerbated. IgM anti-CP14 was followed in 30 patients with chronic hepatitis C during 24 weeks while they received recombinant interferon alpha-2a. IgM anti-CP14 decreased remarkably within 8 weeks in all of them. Thereafter, it continued to decrease in nine patients who responded to interferon and lost HCV RNA from circulation, but started to increase in five non-responders who continued to have high titers of HCV RNA, In the remaining 16 patients in whom HCV RNA decreased once and then increased, IgM anti-CP14 continued to decrease till 20 weeks and then increased. These results indicate that IgM anti-CP14 reflects the activity of liver disease, and is useful in following the outcome of patients with acute hepatitis C and in monitoring the response to interferon in patients with chronic hepatitis C. (C) 1994 Wiley-Liss, Inc.