title: Significance of IgM anti-hepatitis D virus (HDV) in chronic HDV infection.
abstract: Intrahepatic hepatitis D virus (HDV) antigen (HDAg) and serum HDV RNA are excellent markers of active HDV replication but the relation of IgM anti-HDV to HDV replication and histological activity is less certain. To further elucidate the significance of serum IgM anti-HDV, 90 paired sera and liver biopsies from 64 patients seropositive for total antibody to HDV were analysed for IgM anti-HDV, intrahepatic HDAg expression, and histological inflammatory activity. IgM anti-HDV was strongly associated with intrahepatic HDAg expression with a sensitivity of 94.1% but the assay lacked specificity since 14 out of 22 cases negative for intrahepatic HDAg were also positive for IgM anti-HDV. In 20 patients in whom follow-up biopsies and paired sera were available, two patients lost intrahepatic HDAg but paired serum remained IgM anti-HDV positive. Although the presence of serum IgM anti-HDV correlated significantly with a higher histological inflammatory activity (P = 0.001), there was a considerable overlap with the group seronegative for IgM anti-HDV, again indicating a poor specificity. This lack of specificity of IgM anti-HDV for both HDV replication and histological activity indicates that this assay provides no additional information over and above assay for total antibody to HDV.
authors.affiliation: Institute of Liver Studies, King's College Hospital, London, England, United Kingdom.
authors.forename: J Y
authors.initials: JY
authors.lastname: Lau
authors.forename: H M
authors.initials: HM
authors.lastname: Smith
authors.forename: K
authors.initials: K
authors.lastname: Chaggar
authors.forename: L J
authors.initials: LJ
authors.lastname: Hansen
authors.forename: B C
authors.initials: BC
authors.lastname: Portmann
authors.forename: G J
authors.initials: GJ
authors.lastname: Alexander
authors.forename: R
authors.initials: R
authors.lastname: Williams
mesh_terms: D000956:Antigens, Viral / Q000276:immunology*; D005260:Female; D006508:Hepatitis Antibodies / Q000032:analysis*; D003699:Hepatitis D / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D003698:Hepatitis Delta Virus / Q000254:growth & development / Q000276:immunology*; D035923:Hepatitis delta Antigens; D006521:Hepatitis, Chronic / Q000175:diagnosis* / Q000276:immunology / Q000473:pathology; D006801:Humans; D007075:Immunoglobulin M / Q000032:analysis*; D008099:Liver / Q000473:pathology; D008297:Male; D012680:Sensitivity and Specificity; D014779:Virus Replication / Q000276:immunology
chemical_list: D000956:Antigens, Viral; D006508:Hepatitis Antibodies; D035923:Hepatitis delta Antigens; D007075:Immunoglobulin M; C442244:hepatitis delta virus large antigen