Table 1.
Clinical and serological characteristics among patients with anti-MDA5+/− dermatomyositis (DM) and systemic lupus erythematosus (SLE).
| Index | DM | SLE | ||||
|---|---|---|---|---|---|---|
| MDA5− (N = 68) | MDA5+ (N = 217) | p-value | MDA5− (N = 210) | MDA5+ (N = 35) | p-value | |
| Sex, female, n (%) | 28 (41.18) | 84 (38.71) | 0.776 | 192 (91.43) | 33 (94.29) | 0.747 |
| Age (years), mean (SD) | 54.39 (13.14) | 49.91 (11.35) | 0.007 | 36.05 (11.74) | 35.23 (7.00) | 0.687 |
| Heliotrope/Gottron’s, n (%) | 61 (89.71) | 189 (87.10) | 0.675 | – | – | – |
| Malar rash, n (%) | – | – | – | 43 (20.48) | 13 (37.14) | 0.048 |
| Myositis, n (%) | 52 (76.47) | 27 (12.44) | <0.001 | 4 (1.90) | 2 (5.71) | 0.206 |
| ILD, n (%) | 11 (16.18) | 217 (100.00) | <0.001 | 14 (6.67) | 3 (8.57) | 0.718 |
| Fever, n (%) | 7 (10.29) | 139 (64.06) | <0.001 | 11 (5.24) | 0 (0.00) | 0.373 |
| Arthralgia, n (%) | 36 (52.94) | 97 (44.70) | 0.266 | 71 (33.81) | 8 (22.86) | 0.243 |
| LN, n (%) | – | – | – | 55 (26.19) | 12 (34.29) | 0.314 |
| NPSLE, n (%) | – | – | – | 5 (2.38) | 1 (2.86) | >0.999 |
| WBC (103/µl), mean (SD) | 7.46 (2.54) | 6.92 (3.05) | 0.220 | 5.77 (2.67) | 5.29 (1,98) | 0.317 |
| HB (g/L), mean (SD) | 127.89 (26.29) | 124.54 (16.80) | 0.244 | 117.40 (31.10) | 120.00 (41.26) | 0.665 |
| Lymphopenia (<0.8 × 103/µl), n (%) | 11 (16.18) | 128 (58.99) | <0.001 | 55 (26.19) | 14 (40.00) | 0.106 |
| PLT (103/µl), mean (SD) | 209.05 (68.76) | 196.67 (81.51) | 0.298 | 201.22 (82.82) | 201.42 (57.07) | 0.453 |
| CKmax (U/L), mean (SD) | 2450.19 (5349.61) | 279.33 (575.59) | <0.001 | 94.23 (60.32) | 87.26 (74.21) | 0.546 |
| Ferritin (ng/ml), mean (SD) | 841.45 (1032.73) | 1677.12 (2434.33) | 0.032 | 157.43 (177.09) | 115.83 (123.12) | 0.157 |
| C3 (g/L), mean (SD) | 0.95 (0.42) | 1.01 (0.22) | 0.200 | 0.83 (0.26) | 0.88 (0.21) | 0.107 |
| C4 (g/L), mean (SD) | 0.25 (0.10) | 0.26 (0.08) | 0.491 | 0.19 (0.10) | 0.12 (0.06) | 0.209 |
| CRP (mg/L), mean (SD) | 10.87 (24.36) | 11.26 (14.97) | 0.891 | 6.48 (12.86) | 4.08 (8.27) | 0.287 |
| ESR (mm/h), mean (SD) | 28.76 (22.02) | 33.24 (20.74) | 0.128 | 21.39 (22.54) | 23.06 (17.49) | 0.681 |
| IgG (g/L), mean (SD) | 14.08 (4.94) | 15.29 (5.50) | 0.214 | 14.38 (5.06) | 17.17 (5.47) | 0.001 |
| Anti-dsDNA (IU/ml), n (%) | 0 (0.00) | 0 (0.00) | NA | 120 (57.14) | 19 (54.29) | 0.854 |
| Anti-Sm (AI), n (%) | 0 (0.00) | 0 (0.00) | NA | 82 (39.05) | 15 (42.86) | 0.711 |
| Anti-SmRNP (AI), n (%) | 0 (0.00) | 0 (0.00) | NA | 111 (52.86) | 25 (71.43) | 0.045 |
| Anti-Ribo P (AI), n (%) | 0 (0.00) | 0 (0.00) | NA | 65 (30.95) | 12 (34.29) | 0.697 |
| Anti-SS-A52 (AI), n (%) | 3 (4.41) | 139 (64.06) | <0.001 | 83 (39.52) | 13 (37.14) | 0.853 |
| Anti-SS-A60 (AI), n (%) | 0.00 (0.00) | 0.00 (0.00) | NA | 133 (63.33) | 23 (65.71) | 0.851 |
| Anti-MDA5 titer (RU/ml), mean (SD) | 14.23 (6.37) | 186.22 (54.98) | <0.001 | 20.68 (6.47) | 51.68 (17.91) | <0.001 |
Results are depicted as the mean and SD. Student’s t-test was used for continuous variables and Fisher’s exact test for dichotomous variables. MDA5− DM included patients with anti-Mi-2α/β (n = 13), anti-NXP2 (n = 17), anti-SAE1 (n = 15), and anti-TIF1γ (n = 23).
ILD, interstitial lung disease; CKmax, peak plasma CK; LN, lupus nephritis; NPSLE, neuropsychiatric systemic lupus erythematosus; WBC, white blood cell; HB, hemoglobin; PLT, platelet; CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; IgG, immunoglobulin G.
P-value <0.05 is statistically significant in bold text.