Table 2.
Comparison of histopathological features of DM patients with anti‐MDA5 Ab and Ab negative.
| Histopathological features | Anti‐MDA5DM (n = 11) | Ab negative DM (n = 10) | P‐value | |
|---|---|---|---|---|
| Myofiber pathology | Necrotic/Regenerated muscle fibres, n (%) | 6 (54.5) | 9 (90) | 0.149 |
| Atrophic muscle fibres, n (%) | 11 (100) | 10 (100) | NA | |
| Regional perimysial edema, n (%) | 1 (9.1) | 8 (80) | 0.002 * | |
| Perifascicular fiber atrophy, n (%) | 1 (9.1) | 9 (90) | <0.001 * | |
| NADH‐TR activity decreasing fibers, n (%) | 3 (27.3) | 10 (100) | 0.001 * | |
| Vasculopathy | NSE hyperchromatic capillaries, n (%) | 8 (72.7) | 10 (100) | 0.214 |
| Inflammation | Perivascular inflammation, n (%) | 2 (18.2) | 10 (100) | <0.001 * |
| CD3+ T cells infiltrate, n (%) | 3 (27.3) | 9 (90) | 0.008 * | |
| CD4+ T cells infiltrate, n (%) | 4 (36.5) | 9 (90) | 0.024 * | |
| CD8+ T cells infiltrate, n (%) | 2 (18.2) | 7 (70) | 0.030 * | |
| CD20+ B cells infiltrate, n (%) | 1 (9.1) | 6 (60) | 0.024 * | |
| Immune related changes | MHC‐I expression | |||
| Diffuse in muscle fiber membrane, n (%) | 11 (100) | 10 (100) | NA | |
| enhancement in perifascicular region, n (%) | 2 (18.2) | 9 (90) | 0.002 * | |
| MAC‐positive myofiber, n (%) | 2 (18.2) | 8 (80) | 0.009 * | |
| MAC‐positive capillaries, n (%) | 6 (54.5) | 7 (70) | 0.659 | |
| Mitochondrial pathology | COX‐deficient fibers, n (%) | 8 (72.7) | 9 (90) | 0.586 |
| Diffuse COX decreasing fibers, n (%) | 3 (27.3) | 5 (50) | 0.387 | |
| COX‐deficient in perifascicular region, n (%) | 0 (0) | 5 (50) | 0.012 * | |
| Ragged red fibres, n (%) | 2 (18.2) | 3 (30) | 0.635 |
Bold indicates the data that had significant difference after pairwise comparison.
Ab, antibody; NADH‐TR, nicotinamide adenine dinucleotide tetrazolium reductase; MHC‐I, major histocompatibility complex class‐I; MAC, membrane attack complex; COX, cytochrome oxidase C; NSE, nonspecific esterase.
*
P < 0.05.