Background/aims: Autoimmune hepatitis (AIH), an unresolving liver inflammation characterized by periportal hepatitis and presence of serum autoantibodies, is distinguished by smooth muscle antibody and/or antinuclear antibody seropositivity. Type-2 AIH is characterized by antibodies to liver/kidney microsome type-1. Antineutrophil cytoplasmic antibodies (ANCAs) are highly specific for ulcerative colitis, primary sclerosing cholangitis, and, in this report, type-1 AIH determined by positive enzyme-linked immunosorbent assay confirmed by perinuclear indirect immunofluorescence staining. The studies described characterize the frequency and nature of ANCA in severe type-1 AIH patients and define AIH-ANCA specificity and diagnostic significance.
Methods: One hundred four patients, characterized by clinical, immunoserological, virological, histological, and antigenic criteria, were studied. ANCA expression was assayed by enzyme-linked immunosorbent assay.
Results: High-titer ANCA is present in 96% of patients with type-1 AIH with 92% showing a perinuclear staining pattern (pANCA). Whereas many patients were seropositive for antinuclear antibodies, the titer of ANCA did not correlate with the titer of antinuclear antibodies. ANCA expression did not correlate with the presence or absence of other autoimmune disorders. Finally, 80% of patients with AIH examined expressed only immunoglobulin G1 pANCA contrasting with the 33% of patients with PSC with pANCA subclass specificity.
Conclusions: The presence of ANCA seems to be an independent and selective marker for type-1 AIH.