Table 3.
Histological features, treatment, and biopsy site characteristics of DM patients with and without individual DM autoantibodies.
| Jo1+ (n=13) | Jo1- (n=78) | p | Tif1g+ (n=25) | Tif1g- (n=66) | p | NXP2+ (n=17) | NXP2- (n=74) | p | Mi2+ (n=12) | Mi2- (n=79) | p | PMScl+ (n=9) | PMScl- (n=82) | p | MDA5+ (n=5) | MDA5- (n=86) | p | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Perifascicular atrophy | 62% | 49% | 0.6 | 64% | 45% | 0.2 | 53% | 50% | 1 | 67% | 48% | 0.4 | 33% | 52% | 0.3 | 40% | 51% | 0.7 |
| Perivascular inflammation | 69% | 60% | 0.8 | 64% | 61% | 0.8 | 65% | 61% | 1 | 83% | 58% | 0.1 | 78% | 60% | 0.5 | 20% | 64% | 0.1 |
| Primary inflammation | 31% | 22% | 0.5 | 12% | 27% | 0.2 | 0% | 28% | 0.01 | 50% | 19% | 0.03 | 67% | 18% | 0.004 | 0% | 24% | 0.6 |
| Mitochondrial dysfunction | 25% | 29% | 1 | 47% | 18% | 0.05 | 25% | 29% | 1 | 29% | 28% | 1 | 0% | 30% | 0.6 | 50% | 27% | 0.5 |
| Necrotizing myopathy | 15% | 17% | 1 | 8% | 20% | 0.2 | 18% | 16% | 1 | 8% | 18% | 0.7 | 22% | 16% | 0.6 | 0% | 17% | 0.6 |
| Immunosuppresants prior to biopsy | 62% | 61% | 1 | 71% | 57% | 0.3 | 44% | 64% | 0.2 | 58% | 61% | 1 | 56% | 61% | 0.7 | 100% | 58% | 0.2 |
| Immunosuppressants at biopsy | 55% | 55% | 1 | 51% | 67% | 0.2 | 44% | 58% | 0.4 | 50% | 56% | 0.8 | 44% | 56% | 0.5 | 100% | 53% | 0.1 |
| Corticosteroids at biopsy | 31% | 49% | 0.4 | 58% | 42% | 0.2 | 38% | 48% | 0.6 | 50% | 45% | 1 | 33% | 48% | 0.5 | 80% | 44% | 0.2 |
| Days from onset of symptoms to biopsy (median [Q1–Q3]) | 721 (531–874) | 270 (114–497) | 0.02 | 270 (92–561) | 293 (128–721) | 0.5 | 125 (66–293) | 322 (153–777) | 0.01 | 163 (58–402) | 304 (128–663) | 0.1 | 232 (114–1880) | 293 (118–605) | 0.9 | 403 (296–637) | 288 (114–615) | 0.4 |
| Deltoid biopsy | 36% | 42% | 1 | 60% | 34% | 0.06 | 20% | 45% | 0.2 | 29% | 43% | 0.7 | 14% | 44% | 0.2 | 50% | 41% | 1 |
| Biceps biopsy | 9% | 7% | 1 | 0% | 10% | 0.3 | 20% | 5% | 0.1 | 0% | 8% | 1 | 0% | 8% | 1 | 0% | 8% | 1 |
| Quadriceps biopsy | 55% | 51% | 1 | 40% | 56% | 0.3 | 60% | 50% | 0.7 | 71% | 49% | 0.4 | 86% | 48% | 0.1 | 50% | 51% | 1 |