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.