Table 5.
Nonstandard Antibodies for the Diagnosis of Autoimmune Hepatitis
| Nonstandard antibodies | Antigenic target(s) | Clinical features |
|---|---|---|
| Antibodies to actin (antiactin) | Filamentous (F) actin162 | Present in 87% with AIH162,170,172 |
| Nonactin components162 | Concurrent with SMA in 86%–100% with AIH162,173 | |
| SMA without antiactin in 14% with AIH162 | ||
| Indirect marker of disease activity159,162 | ||
| No standardized assay162,177 | ||
| Antibodies to α-actinin (anti-α-actinin) | α-Actinin178 | Present in 42% of patients with AIH27 |
| Antiactin+anti-α-actinin associated with severity27 | ||
| Baseline level predictive of treatment response30 | ||
| Investigational assay not generally available27,30 | ||
| Antibodies to soluble liver antigen (anti-SLA) | Sep (O-phosphoserine) tRNA:Sec (selenocysteine) tRNA synthase (SEPSECS)23,182,183 | Present in 7%–22% with AIH26,31,87,179,180 |
| Genetic association with HLA DRB1*030124,25 | ||
| Associated with severity, response, relapse, survival24–26 | ||
| Useful in diagnosing seronegative patients159,180,181 | ||
| Specificity, 99%, and sensitivity, 11%179 | ||
| Atypical perinuclear antineutrophil cytoplasmic antibodies (pANCA) | β-Tubulin isotype 5189 | Cross reacts with precursor bacterial protein (FtsZ)189 |
| Present in 50%–92% with typical AIH88,187–189 | ||
| Absent in anti-LKM1-positive AIH190 | ||
| Detected in CUC, PSC, PBC, minocycline injury188,191,193 | ||
| Useful in classifying seronegative AIH17,76,171,195 | ||
| Antibodies to asialoglycoprotein receptor (anti-ASGPR) | Asialoglycoprotein receptor198,199 | Present in 67%–88% with AIH28,198–201 |
| Occurs in other acute and chronic liver diseases198,203,204 | ||
| Useful in classifying seronegative AIH205 | ||
| Correlates with laboratory and histological activity206 | ||
| May predict relapse and define treatment end points201,206 | ||
| Antibodies to liver cytosol type 1 (anti-LC1) | Formiminotransferase cyclodeaminase219–222 | Present in 24%–32% of anti-LKM1-positive AIH208–210 |
| Occurs in chronic hepatitis C and anti-LKM1211–214 | ||
| Useful in classifying seronegative AIH217,218 | ||
| Rare in North American adults with AIH216 |
AIH, autoimmune hepatitis; SMA, smooth muscle antibodies; HLA, human leukocyte antigen; anti-LKM1, antibodies to liver kidney microsome type 1; CUC, chronic ulcerative colitis; PSC, primary sclerosing cholangitis; PBC, primary biliary cholangitis.