Serum immunological profile in patients with chronic autoimmune cholestasis

To compare patients who had biochemical and histological features of chronic autoimmune cholestasis (CAIC) using serological autoantibody profiling.

Patients (n = 174 CAIC; 79 AMA(-) and 95 AMA(+)) were profiled for the following antibodies: antinuclear antibodies (ANAs), antimitochondrial antibodies (AMAs), antismooth muscle actin (SMA, mainly F-actin), antiperinuclear cytoplasmic neutrophil antibodies (pANCAs), anti-SP100, anti-GP210, anti-M2 (2-oxo-acid dehydrogenase complexes), and antisoluble liver antigen (SLA). Liver specimens were reviewed according to staging, biliary interface activity, lobular hepatitis, granulomas, cholestasis, and florid ductal lesion.

In patients who were AMA(-) by indirect immunofluorescence (IIF), 34.6% were positive for anti-M2 by immunoblotting. In 49 definitively AMA(-) patients, 24 (48.9%) showed ANA-primary biliary cirrhosis (PBC)-related antibodies (rim-like, multiple nuclear dots, anti-SP100, or anti-GP210). There were no differences in immunological, biochemical, or histopathological features between IIF-AMA(+) patients and AMA(-) patients with anti-M2 or ANA-PBC-related antibodies. AIH-related autoantibodies were found in 13 patients (7.5%). Patients with AMAs or ANA-PBC-related antibodies had higher IgM levels, whereas patients with antibodies highly specific for AIH had higher AST, bilirubin, and IgG levels, and AIH scores, and higher grades of lobular hepatitis. Overall, three distinct categories of patients were observed: AMA(+) or AMA(-) patients with ANA-PBC-related antibodies; AMA(-) patients with non-PBC-related ANAs; and patients with AIH-related antibodies together with serum PBC markers.

Since these three groups had immunological, biochemical, and histopathological differences, they ought to be considered as separate clinical subentities rather than as merely AMA(-) or AMA(+) patients with autoimmune cholestasis.