Table 1 Summary of the clinical characteristics and laboratory data

Sex (male/female)

2/9

5/7

2/9

4/9

5/10

Age (%)

66.0 (58.0–72.5)

68.5 (62.3–71.3)

65.0 (53.5–68.0)

68.0 (51.0–78.0)

63.0 (60.5–69.0)

Smoking history (%)

1 (9 %)

6 (50 %)

3 (27 %)

2 (15 %)

6 (40 %)

Days from onset

  To 1st visit

44.0 (14.0–109)

184 (59.0–761)

68.0 (29.5–96.5)

97.0 (63.0–238)

17.0 (9.50–38.5)

  To treatment

62.0 (24.0–151)

235 (133–902)

80.0 (50.3–175)

127 (108–282)

31.0 (15.5–100)

  Respiratory medicine

8 (73 %)

0

4 (36 %)

0

9 (60 %)

  Rheumatology

3 (27 %)

4 (33 %)

6 (55 %)

8 (62 %)

4 (27 %)

  Neurology

0

8 (67 %)

1 (9 %)

3 (23 %)

0

  Dermatology

0

0

0

2 (15 %)

2 (13 %)

Skin

  Gottron’s sign / papule

0

0

6 (55 %)

10 (77 %)

9 (60 %)

  Heliotrope eruption

0

0

3 (27 %)

10 (77 %)

8 (53 %)

  V / Shawl neck sign

0

1 (8 %)

4 (36 %)

6 (46 %)

4 (27 %)

  Mechanic’s hands

0

0

2 (18 %)

1 (8 %)

2 (13 %)

Muscle

  Myalgia

3 (27 %)

5 (42 %)

8 (73 %)

2 (15 %)

4 (27 %)

  Muscle weakness

10 (91 %)

12 (100 %)

6 (55 %)

13 (100 %)

0

Lung

  Dry cough

5 (45 %)

0

3 (27 %)

0

9 (60 %)

  Dyspnea on exertion

2 (18 %)

1 (8 %)

2 (18 %)

0

9 (60 %)

Others

  Fever

8 (73 %)

1 (8 %)

7 (64 %)

1 (8 %)

12 (80 %)

Laboratory data

  C-reactive protein (mg/dl)

1.06 (0.535–3.28)

0.125 (0.0800–0.320)

0.730 (0.330–1.96)

0.320 (0.110–0.610)

1.27 (0.495–2.92)

  Krebs von den Lungen-6 (U/ml)

870 (568–1340)

273 (127–288)

648 (297–1020)

241 (234–289)

905 (596–1197)

  Surfactant protein D (ng/dl)

119 (68.8–180)

52.3 (45.2–62.0)

70.1 (45.5–182)

23.1 (17.2–73.3)

64.7 (29.8–117)

  Aspartate aminotransferase (IU/l)

85.0 (62.0–150)

51.5 (35.5–100)

66.0 (48.0–157)

68.0 (54.0–158)

40.0 (28.5–56.5)

  Alanine aminotransferase (IU/l)

50.0 (31.5–111)

27.0 (16.5–75.0)

50.0 (29.0–79.5)

43.0 (28.0–101)

20.0 (17.0–32.5)

  Lactate dehydrogenase (IU/l)

571 (429–772)

317 (263–670)

496 (357–645)

513 (441–759)

342 (283–381

  Creatine phosphokinase (IU/l)

1547 (599–2657)

1212 (402–3347)

874 (270–3000)

965 (617–4872)

232 (108–316)

  Aldolase (U/l)

28.5 (11.1–45.2)

18.1 (5.15–22.8)

15.5 (7.75–31.9)

11.4 (8.40–30.9)

7.40 (3.45–8.95)

  Antinuclear antibody (%)

8 (73 %)

7 (58 %)

7 (64 %)

9 (69 %)

8 (53 %)

  Anti-Jo-1 antibody (%)

1 (9 %)

0

1 (9 %)

1 (8 %)

0

  Anti-MDA5 antibody

NA

NA

NA

NA

8/13

Lung function test

  %Forced vital capacity

76.5 (59.8–93.8)

NA

76.5 (53.0–81.7)

NA

83.1 (70.4–91.3)

  %Diffusing capacity for carbon monoxide

65.7 (56.0–73.6)

NA

61.3 (47.1–64.0)

NA

58.2 (54.6–62.4)