Hepatitis C virus (HCV)
infection has been found to be strikingly associated with autoimmune phenomena. The aim of the present study was to investigate the presence of various
autoantibodies in patients with HCV
infection. Anti-neutrophil cytoplamic antibody (
ANCA), anti-
dihydrolipoamide dehydrogenase (anti-E3),
rheumatoid factor (RF), anti-
dihydrolipoamide acetyltransferase (anti-E2), anti-SS-A/Ro (60 kD), anti-SS-A/Ro (52 kD),
anti-SS-B/La, anti-
topoisomerase II (anti-
topo II), anti-
cardiolipin (aCL), anti-dsDNA, anti-ssDNA, anti-nuclear
antibodies (ANA), anti-
proteinase 3 (anti-Pr3) and anti-
myeloperoxidase (anti-MPO) were determined in sera from 516 patients with HCV
infection, 11 with
primary biliary cirrhosis (PBC) and 44 healthy controls. Assays employed were indirect immunofluoresence, the
particle latex agglutination test,
enzyme-linked
immunosorbent assay (ELISA) and immunoblotting.
ANCA, anti-E3 antibody and RF were positive in 278/516 (55.6%), 276/516 (53.3%) and 288/516 (56%) patients with HCV
infection, respectively. Positivity for ANA was present in 15.8%, anti-ssDNA in 15.6%, anti-dsDNA in 8.5%, aCL in 5%,
anti-SS-B/La in 4.1%, anti-SS-A/Ro (60 kD) in 3.9%, anti-E2 in 3.3% and anti-SSA/Ro (52 kD) in 1.2%, anti-MPO in 4.8%, anti-
Topo II and anti-
actinin in 0%. All sera with
ANCA showed
c-ANCA patterns and contained anti-PR3 specificity. HCV patients with
ANCA showed a higher prevalence of skin involvement, anaemia, abnormal liver function and
alpha-Fetoprotein (alpha-FP). HCV patients with anti-E3
antibodies showed a higher prevalence of
liver cirrhosis,
arthritis, abnormal liver function and elevated alpha-FP levels. The prevalence of
autoantibodies was not affected by treatment with
interferon-alpha (IFN-alpha). In conclusion,
autoantibodies are commonly found in patients with HCV
infection. There is a high prevalence of anti-E3,
ANCA and RF in these patients.
Proteinase 3 and E3 are the major target
antigens in HCV
infection. HCV may be regarded as a possible causative factor in
ANCA-related
vasculitis.