Table 2.
Muscle biopsy features, treatments, and duration of disease at biopsy according to autoantibody subsets in DM patients.
| All DM (n=91) |
All Jo-1 (n=13; 14%) |
Jo-1 with Ro-52 (n=9; 10%) |
Jo-1 without Ro-52 (n=4; 4%) |
Anti-Tif1γ (n=25; 27%) |
NXP2 (n=17; 19%) |
Mi2 (n=12; 13%) |
MDA5 (n=5; 5%) |
PM-Scl (n=9; 10%) |
Ro52 (n=22; 24%) |
No Antibody (n=15; 16%) |
|
|---|---|---|---|---|---|---|---|---|---|---|---|
| Perivascular inflammation | 56 (62%) | 9 (69%) | 8 (89%) | 1 (25%) | 16 (64%) | 11 (65%) | 10 (83%) | 1 (20%) | 7 (78%) | 15 (68%) | 6 (40%) |
| Perifascicular atrophy | 46 (51%) | 8 (62%) | 7 (78%) | 1 (25%) | 16 (64%) | 9 (53%) | 8 (67%) | 2 (40%) | 3 (33%) | 12 (55%) | 4 (27%) |
| Primary inflammation | 21 (23%) | 4 (31%) | 4 (44%) | 0 (0%) | 3 (12%) | 0 (0%) | 6 (50%) | 0 (0%) | 6 (67%) | 6 (27%) | 3 (20%) |
| Mitochondrial dysfunction* | 14 (28%) | 2 (25%) | 2 (29%) | 0 (0%) | 7 (47%) | 2 (25%) | 2 (29%) | 1 (50%) | 0 (0%) | 4 (29%) | 1 (14%) |
| Necrotizing myopathy | 15 (16%) | 2 (15%) | 0 (0%) | 2 (50%) | 2 (8%) | 3 (18%) | 1 (8%) | 0 (0%) | 2 (22%) | 4 (18%) | 4 (27%) |
| Immunosuppresants prior to biopsy | 55 (61%) | 8 (62%) | 6 (67%) | 2 (50%) | 17 (71%) | 7 (44%) | 7 (58%) | 5 (100%) | 5 (56%) | 15 (68%) | 9 (60%) |
| On immunosuppressants during biopsy | 49 (56%) | 6 (55%) | 5 (63%) | 1 (33%) | 16 (67%) | 7 (44%) | 6 (50%) | 4 (100%) | 4 (44%) | 17 (81%) | 6 (40%) |
| Corticosteroids during biopsy | 42 (47%) | 4 (31%) | 3 (33%) | 1 (25%) | 14 (58%) | 6 (38%) | 6 (50%) | 4 (80%) | 3 (33%) | 14 (64%) | 5 (33%) |
| Days from the onset of symptoms to the biopsy (median [Q1–Q3]) | 290 (117–615) |
721 (531 −874) |
721 (599–1022) |
654 (275–802) |
270 (92 −561) |
125 (66–293) |
163 (58–402) |
403 (296–637) |
232 (114–1880) |
497 (291–874) |
435 (289–919) |
*
Since not all biopsies were stained with COX, mitochondrial dysfunction could not be assessed in all cases