Characteristics of anti-Ku-positive patients with IIM
| Features | Isolated anti-Ku (n=11) | Coexistence of anti-Ku and MSA (n=10) |
| Female | 10 (90.9%) | 10 (100%) |
| Age of onset | 45.55±16.45 | 39.00±11.47 |
| Duration(months) | 12(3,72) | 29(4,60) |
| Diagnosis | ||
| DM | 2 (18.2%) | 6 (60%) |
| PM | 8 (72.7%) | 3 (30%) |
| PM+SSc | 1 (9.1%) | 0 |
| DM+SSc | 0 | 1 (10%) |
| MSA | ||
| MDA5 | – | 3 (14.8%) |
| NXP2 | – | 1 (4.8%) |
| TIF1γ | – | 2 (9.5%) |
| Jo-1 | – | 1 (4.8%) |
| PL-12 | – | 1 (4.8%) |
| PL-7 | – | 1 (4.8%) |
| SRP | – | 1 (4.8%) |
| MAA | ||
| Ro-52 | 1 (9.1%) | 5 (50%) |
| PM-Scl 75/100 | 0 | 2 (20%) |
| Muscle Weakness | 8 (72.7%) | 8 (80%) |
| Dysphagia | 2 (18.2%) | 5 (50%) |
| Neck weakness | 1 (8.3%) | 1 (10%) |
| Myalgia | 6 (54.5%) | 4 (40%) |
| Skin involvement* | 2 (18.2%) | 7 (70%) |
| Raynaud’s phenomena | 3 (27.3%) | 2 (20%) |
| ILD | 8 (72.7%) | 8 (80%) |
| FVC% of predicted value† | 74.05±12.84 | 93.21±18.54 |
| DLco% of predicted value‡ | 59.61±15.41 | 76.03±14.15 |
| Arthritis | 3 (25%) | 2 (20%) |
| Cancer | 0 | 0 |
| Increased CK | 10 (90.9%) | 5 (50%) |
| Pathological pattern | n=7 | n=6 |
| IMNM | 6 | 1(anti-PL-7 positive) |
| pDM | 0 | 2(anti-MDA5 and -TIF1γ positive) |
| NSM | 1 | 1(anti-Jo-1 positive) |
| Normal | 0 | 2(anti-MDA5 and -TIF1γ positive) |
FVC and DLco value were available for 8 patients with isolated anti-Ku and 7 patients with anti-Ku coexistence of MSA.
*P=0.03.
†P=0.035.
‡P=0.049.
CK, creatine kinase; DLco, carbon monoxide diffusion capacity; DM, dermatomyositis; FVC, forced vital capacity; ILD, interstitial lung disease; IMNM, immune-mediated necrotizing myopathie; MAA, myositis-associated autoantibodies; MSA, myositis-specific autoantibodies; NSM, non-specific myositis; pDM, pathologic DM; PM, polymyositis; SSc, systemic sclerosis.