Table 1:
Rates of myositis panel positive autoantibody testing by final diagnosis
| Myositis Panel | MSA from Myositis Panel | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Any MSA | Any MAA | Jo-1 | Mi-2 | PL-7 | PL-12 | p155/140 | EJ | OJ | SRP | |
| Definite/Probable PM | 2 | 1 | 0 / 16 | 0 | 0 | 0 | 0 / 13 | 0 | 0 | 2 / 14 |
| n = 17 | (12 %) | (6 %) | (0 %) | (0 %) | (0 %) | (0 %) | (0 %) | (0 %) | (0 %) | (14 %) |
| Definite/Probable DM | 6 | 6 | 0 / 25 | 3 | 1 | 0 | 2 / 19 | 0 | 0 | 0 / 22 |
| n = 26 | (23 %) | (23 %) | (0 %) | (12 %) | (4 %) | (0 %) | (11 %) | (0 %) | (0 %) | (0 %) |
| Definite CADM | 3 | 9 | 1 / 32 | 0 | 0 | 1 | 1 / 24 | 0 | 0 | 0 / 28 |
| n = 33 | (9 %) | (27 %) | (3 %) | (0 %) | (0 %) | (3 %) | (4 %) | (0 %) | (0 %) | (0 %) |
| Possible PM/DM/CADM | 9 | 11 | 2 | 1 | 2 | 2 | 1 / 36 | 0 | 1 | 0 / 37 |
| n = 48 | (19 %) | (23 %) | (4 %) | (2 %) | (4 %) | (4 %) | (3 %) | (0 %) | (2 %) | (0 %) |
| Overlap Autoimmune Disease | 5 | 14 | 1 | 1 | 1 | 1 | 0 / 22 | 1 | 1 | 0 / 22 |
| n = 26 | (19 %) | (54 %) | (4 %) | (4 %) | (4 %) | (4 %) | (0 %) | (4 %) | (0 %) | (0 %) |
| ILD without myositis | 10 | 18 | 2 | 1 | 1 | 5 | 0 / 95 | 0 | 0 | 1 /98 |
| n = 102 | (10 %) | (18 %) | (2 %) | (1 %) | (1 %) | (5 %) | (0 %) | (0 %) | (0 %) | (1 %) |
| None of the above | 3 | 12 | 1 | 1 | 0 | 0 | 0 / 82 | 0 | 0 | 1 / 90 |
| n = 103 | (3 %) | (12 %) | (1 %) | (1 %) | (0 %) | (0 %) | (0 %) | (0 %) | (0 %) | (1 %) |
Definite/Probable PM or DM = 3–4 Bohan and Peter’s Criteria; Possible DM or PM = 2 Bohan and Peter’s Criteria; Definite CADM = consistent rash and skin biopsy; Possible CADM = consistent rash without biopsy; Overlap Autoimmune Disease = myositis due to non-IIM systemic autoimmune disease. MSA = myositis specific antibody; MAA = myositis associated antibody [Ku, PM-Scl, Ro-52, Ro-60, u1-RNP, or u2-RNP]; PM = polymyositis; DM = dermatomyositis; CADM = clinically amyopathic dermatomyositis; ILD = interstitial lung disease