Diagnosis of hepatitis C virus related acute hepatitis by serial determination of IgM anti-HCV titres

Background/Aims We investigated whether serial determination of IgM to HCV core protein (HCV IgM) may be useful to identify acute hepatitis C (AHC) and to distinguish this disease from reactivation of chronic hepatitis C (r-CHC). Methods We enrolled 35 consecutive patients with AHC identified by seroconversion to anti-HCV and 31 consecutive patients who had been anti-HCV positive for at least six months at the time of reactivation. Titres of HCV IgM were calculated as Index values by a commercially available enzyme immunoassay. Results During the early phase of the illness we observed a wide variation in the HCV IgM Index values in all patients in the AHC group and consistent values in all cases in the r-CHC group. The HCV viral load determined soon after the onset of symptoms was of no use in identifying AHC.Twenty-three patients in the AHC group were observed as outpatients for 6-30 months; of these, 10 became plasma HCV-RNA negative within the third month of observation, but three showed a subsequent reactivation of HCV infection. Conclusions Our data indicate that the detection of high and variable titres of HCV IgM in the early phase of the illness may identify acute hepatitis C and allow early antiviral treatment.