Comparison of the proportion of positive cases in each group
| Pathological features | IBM+RV | PAM | IBM+RV vs PAM | IBM - RV | PM&DM | IBM - RV vs PM&DM | IBM+RV vs IBM - RV | ||
|---|---|---|---|---|---|---|---|---|---|
| n (%) | n (%) | Sensitivity | Specificity | n (%) | n (%) | Sensitivity | Specificity | p value | |
| Number of cases | 15 (100) | 7 (100) | 9 (100) | 11 (100) | |||||
| Aggregated proteins, n (%) | |||||||||
| p62 | 15 (100) | 6 (86) | 1.00 | 0.14 | 4 (44) | 3 (27)* | 0.44 | 0.73 | 0.003† |
| TDP-43 | 13 (87) | 5 (71) | 0.87 | 0.29 | 1 (11) | 2 (18)* | 0.11 | 0.82 | 0.001† |
| Ubiquitin | 11 (73) | 4 (57) | 0.73 | 0.43 | 0 (0) | 3 (27)* | 0.00 | 0.73 | 0.001† |
| Myotilin | 10 (67) | 5 (71) | 0.67 | 0.29 | 0 (0) | 9 (82) | 0.00 | 0.18 | 0.002† |
| Congophilic deposits | 13 (87) | 7 (100) | 0.87 | 0.00 | 1 (11) | 0 (0) | 0.11 | 1.00 | 0.001† |
| COX−/SDH+ fibres‡, n (%) | |||||||||
| Any | 12 (86) | 2 (29) | 0.86 | 0.71 | 9 (100) | 3 (27) | 1.00 | 0.73 | 0.50 |
| Inflammatory features, n (%) | |||||||||
| MHC class I upregulation | 15 (100) | 3 (43) | 1.00 | 0.57 | 9 (100) | 11 (100) | 1.00 | 0.00 | 1.00 |
| Strong MHC class I upregulation | 14 (93) | 0 (0) | 0.93 | 1.00 | 7 (78) | 10 (91) | 0.78 | 0.09 | 0.53 |
| Partial invasion | 10 (67) | 0 (0) | 0.67 | 1.00 | 3 (33) | 2 (18) | 0.33 | 0.82 | 0.21 |
| Endomysial CD3 T-cell score >1 | 13 (87) | 0 (0) | 0.87 | 1.00 | 4 (44) | 7 (64) | 0.44 | 0.36 | 0.06 |
| Endomysial CD4 T-cell score >1 | 12 (80) | 0 (0) | 0.80 | 1.00 | 2 (22) | 5 (45) | 0.22 | 0.54 | 0.01† |
| Endomysial CD8 T-cell score >0 | 14 (93) | 0 (0) | 0.93 | 1.00 | 7 (78) | 9 (82) | 0.78 | 0.18 | 0.53 |
| Endomysial CD68 macrophage score >1 | 12 (80) | 0 (0) | 0.80 | 1.00 | 4 (44) | 8 (73) | 0.44 | 0.27 | 0.10 |
*Pathological features present in DM, but not PM cases.
†Statistically significant results.
‡In IBM with rimmed vacuoles n=14.
COX, cytochrome oxidase; IBM, inclusion body myositis; MHC, major histocompatibility complex; PAM, protein accumulation myopathies with rimmed vacuoles; PM&DM, steroid-responsive inflammatory myopathies; RV, rimmed vacuoles; SDH, succinate dehydrogenase; TDP-43, transactivation response DNA binding protein-43.