HIGH-TITER ANTINEUTROPHIL CYTOPLASMIC ANTIBODIES IN TYPE-1 AUTOIMMUNEHEPATITIS

Background/Aims: Autoimmune hepatitis (AIH), an unresolving liver infl ammation characterized by periportal hepatitis and presence of serum a utoantibodies, is distinguished by smooth muscle antibody and/or antin uclear antibody seropositivity. Type-2 AIH is characterized by antibod ies to liver/kidney microsome type-1. Antineutrophil cytoplasmic antib odies (ANCAs) are highly specific for ulcerative colitis, primary scle rosing cholangitis, and, in this report, type-1 AIH determined by posi tive enzyme-linked immunosorbent assay confirmed by perinuclear indire ct 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 hundre d four patients, characterized by clinical, immunoserological, virolog ical, histological, and antigenic criteria, were studied. ANCA express ion was assayed by enzyme-linked immunosorbent assay. Results: High-ti ter ANCA is present in 96% of patients with type-1 AIH with 92% showin g a perinuclear staining pattern (pANCA). Whereas many patients were s eropositive for antinuclear antibodies, the titer of ANCA did not corr elate with the titer of antinuclear antibodies. ANCA expression did no t correlate with the presence or absence of other autoimmune disorders . Finally, 80% of patients with AIH examined expressed only immunoglob ulin G1 pANCA contrasting with the 33% of patients with PSC with pANCA subclass specificity. Conclusions: The presence of ANCA seems to be a n independent and selective marker for type-1 AIH.