SERUM IMMUNOGLOBULIN-M ANTIBODY TO HEPATITIS-D AS A SURROGATE MARKER OF HEPATITIS-D IN INTERFERON-TREATED PATIENTS AND IN PATIENTS WHO UNDERWENT LIVER-TRANSPLANTATION

The kinetics of the immunoglobulin (Ig) M type antibody to the hepatit is D virus (IgM anti-HD) were investigated in hepatitis B surface anti gen (HBsAg) carriers with chronic hepatitis D treated with interferon (IFN) and in patients with terminal hepatitis delta virus (HDV) cirrho sis who underwent liver transplantation. The IgM antibody disappeared in each of 8 patients who responded to IFN therapy with the persistent normalization of aminotransferases and with the clearance of serum HB sAg and HDV-RNA. The IgM reactivity did not decline in the 45 treated patients who did not respond to the cytokine or who experienced a rela pse after responding while on therapy, The antibody rapidly disappeare d from serum post-transplantation in each of 10 examined patients with HDV who underwent transplantation. In 5 patients who underwent transp lantation and who became reinfected with HDV, the antibody remained un detectable during the early reinfection phase, as marked by HDV replic ation and by the absence of liver damage; however, it rapidly raised t o pre-transplantation levels with the recurrence of hepatitis D (HD) i n the liver graft, Monomeric 7S IgM anti-HD predominated over pentamer ic 19S antibody in each of the two patients examined for IgM anti-HD m olecular species, The IgM antibody to HDV raises in response to HDV-in duced damage and represents a valid surrogate marker of liver damage w hich is immunopathologically related to HDV infection, Besides providi ng diagnostic information, it provides the best predictor of impending resolution of chronic HDV disease, whether spontaneous or IFN-induced .