Table 3.
Performance of parameters of the humoral autoimmune response according to their ability to classify the 212 samples as associated with definite primary biliary cirrhosis (PBC or PBC/AID)
| Serologic parameter | Ranges | Classification as PBC or PBC/AID | |||||
|---|---|---|---|---|---|---|---|
| Se | Sp | PPV | NPV | Accuracy | OR (95 % CI) | ||
| (Values expressed in percentage) | |||||||
| IIF-AMA titer | Low (0–1/80) | 13.1 | 52.4 | 30.4 | 27.6 | 28.3 | 0.72 (0.174–4.12) |
| (1/160–1/320) | 26.9 | 69.5 | 58.3 | 37.5 | 43.4 | 4.00 (1.82–8.79) | |
| High (≥1/640) | 60.0 | 79.3 | 82.1 | 55.6 | 67.5 | 11.70 (5.35–25.63) | |
| IIF-AMA isotypes | Negative or 1 | 23.1 | 53.7 | 44.1 | 30.6 | 34.9 | 1.73 (0.47-6.43) |
| 2 | 39.2 | 67.1 | 65.4 | 41.0 | 50.0 | 3.77 (1.04–13.69) | |
| 3 | 37.7 | 79.3 | 74.2 | 44.5 | 54.0 | 5.76 (1.54–21.60) | |
| Anti-PDC-E2 levelsa | ≥3.0 IU/mL | 68.5 | 61.0 | 73.6 | 55.0 | 65.6 | 3.51 (1.97–6.27) |
| Anti-PDC-E2 avidityb | ≥64 % | 67.7 | 73.2 | 80.0 | 58.8 | 69.8 | 5.71 (3.10–10.53) |
| WB-AMA | ≥2 proteins | 61.5 | 57.3 | 69.6 | 48.5 | 59.9 | 2.14 (1.22–3.77) |
| Antigenic cell domains | ≥3 targets | 20.0 | 97.6 | 92.9 | 43.5 | 50.0 | 10.00 (2.31–43.38) |
Se sensitivity, Sp specificity, PPV and NPV positive and negative predictive value, respectively, OR odds ratio, 95 % CI 95 % confidence interval, WB-AMA Western blot for antimitochondria antibodies
aROC curve for anti-PDC-E2 serum levels, AUC = 0.679 (0.606–0.751)
bROC curve for anti-PDC-E2 avidity, AUC = 0.704 (0.633–0.755)