Introduction
Methods of Detection
Anti-Nuclear Antibody
Autoantibody | Autoantigens | Methods of detection | Frequency in AIH | Presence in other liver diseases | Clinical significance | Comments |
---|---|---|---|---|---|---|
ANA | Single- and double-stranded DNA Nuclear chromatin Histones Centromeres Cyclin A Ribonucleoproteins Unknown in at least 30% | IIF Solid-phase assays | 60–70% | Drug-induced liver injury Viral hepatitis B, C, E Wilson PSC ASC PBC Fatty liver disease | Defines AIH-1, associated with SMA in 50% of the cases | IIF: homogeneous pattern in 2/3; speckled or nucleolar in 1/3 |
Anti-SMA | Filamentous actin Desmin Vimentin Unknown in 20% | IIF Solid-phase assay for anti-actin | Up to 85% | Drug-induced liver injury Viral hepatitis B, C, E Wilson PSC ASC Fatty liver disease | Strongly favors AIH-1 diagnosis, particularly if combined with ANA and at high titers | Titer correlates with disease activity in juvenile AIH-1 VG/VGT IIF patterns typical of AIH-1 |
Anti-LKM1 | Cytochrome P4502D6 (CYP2D6) | IIF Solid-phase assays | At least 70% in AIH-2 | Chronic hepatitis C | Diagnostic of AIH-2 after exclusion of hepatitis C | Titer correlates with disease activity in AIH-2 |
Anti-LC1 | Formiminotransferase cyclodeaminase (FTCD) | IIF Solid-phase assays | 30% in AIH-2 | Very rare in hepatitis C, often with anti-LKM1 | Diagnostic of AIH-2 after exclusion of hepatitis C | May be the only autoantibody in AIH-2 Titer correlates with disease activity in AIH-2 |
Anti-SLA | O-phosphoseryl-tRNA(Sec) selenium transferase | Solid-phase assays | Up to 20–30% in AIH-1 and AIH-2 | Very rare in hepatitis C ASC | Diagnostic of AIH | Associated with more aggressive disease |
pANNA | Betatubulin isotype 5 High-mobility group non-histone chromosomal proteins HMG1 and HMG2 Histone H1 Lactoferrin Elastase Catalase Alpha-enolase Bactericidal/permeability-increasing protein Other unknown antigens | IIF | 20–96% in AIH-1 | ASC PSC | May be the only autoantibody in AIH-1 PSC/ASC and inflammatory bowel disease should be excluded in pANNA-positive cases | Associated with inflammatory bowel disease Absent in AIH-2 |