Immunochemical and biomolecular studies of circulating immune complexes isolated from patients with acute and chronic hepatitis C virus infection.
Circulating immune complexes (ICs) were isolated by affinity chromatography and sucrose density gradient fractionation during acute and chronic hepatitis C virus (HCV) infection. Immunochemical and biomolecular studies showed that they basically consist of the virus component, IgG with specific anti-HCV activity and IgM bearing 17.109 epitope (IgM 17.109), an antigenic determinant common to rheumatoid factors (RFs) with WA cross-idiotype (XId). An antigen-specific IC assay was used to demonstrate IgG anti-HCV/IgM 17.109 ICs (IgG-IgM ICs) in five out of the five patients with acute and in 8 out of the 10 patients with chronic hepatitis C who mounted an IgG anti-HCV immune response. They were not detected in patients with no IgG anti-HCV response. IgG-IgM ICs appeared in step with IgG anti-HCV seroconversion and remained detectable for a long period irrespective of clinical outcome, in that they were demonstrated over a 4-year follow-up of patients with chronic hepatitis C. Their presence was unrelated to the severity and progression of liver histology. Despite similar serum levels of IgM 17.109 XId, antigen-specific IgG-IgM ICs were not found in acute and chronic hepatitis B or in acute hepatitis A. Thus, these ICs appear to be uniquely associated with HCV infection, supporting the view that IgM 17.109 XId derive from an antigen-driven response strictly related to the involved antigen. Even although they have no apparent effects on the progression of HCV-related liver disease, their presence may help to explain the immunological abnormalities and extrahepatic disorders observed in HCV infection.
Sansonno
D
D
Department of Biomedical Sciences and Human Oncology, University of Bari Medical School, Italy.
Iacobelli
A R
AR
Cornacchiulo
V
V
Lauletta
G
G
Distasi
M A
MA
Gatti
P
P
Dammacco
F
F
D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000936:Antigen-Antibody Complex / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D001706:Biopsy; D015153:Blotting, Western; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006506:Hepatitis A / Q000276:immunology; D006509:Hepatitis B / Q000276:immunology; D006526:Hepatitis C / Q000276:immunology*; D006521:Hepatitis, Chronic / Q000276:immunology; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D008099:Liver / Q000473:pathology; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D012367:RNA, Viral / Q000097:blood; D013997:Time Factors
D000936:Antigen-Antibody Complex; D015415:Biomarkers; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D012367:RNA, Viral