Table 1 Baseline demographic and clinical characteristics in the MSC group

Sex, n (%)

0.455

Male

8 (47.06)

16 (53.33)

4 (66.67)

5 (100.00)

Female

9 (52.94)

14 (46.67)

2 (33.33)

0 (0.00)

Age (years)

59.20 (8.74)

58.75 (10.06)

64.17 (9.97)

54.75 (8.73)

0.188

BMI (kg/m²)

24.10 [21.90, 26.50]

26.00 [23.18, 27.68]

25.40 [24.08, 27.78]

26.15 [25.05, 26.88]

0.855

Comorbidities, n (%)

1.000

 No

8 (47.06)

14 (46.67)

2 (33.33)

2 (40.00)

 Yes

9 (52.94)

16 (53.33)

4 (66.67)

3 (60.00)

White blood cell count (× 10⁹/L)

5.90 [5.00, 7.30]

5.60 [4.78, 7.10]

5.85 [5.43, 6.68]

5.50 [5.23, 5.93]

0.646

Neutrophil cell count (× 10⁹/L)

3.49 [2.85, 4.97]

3.57 [2.83, 4.38]

3.70 [3.07, 4.50]

3.38 [3.21, 3.64]

0.465

Lymphocyte cell count (× 10⁹/L)

1.65 (0.47)

1.43 (0.51)

1.54 (0.34)

1.44 (0.38)

0.933

Platelet count (× 10⁹/L)

250.20 (80.01)

230.00 (79.28)

196.33 (16.35)

214.25 (46.62)

0.277

IL-6 (pg/mL)

9.33 [8.08, 17.60]

7.32 [4.31, 11.43]

6.59 [5.79, 9.04]

6.75 [6.20, 7.68]

0.854

Time from symptom onset to MSC treatment (days)

47.00 [43.00, 53.00]

45.00 [34.25, 47.00]

55.50 [34.00, 57.25]

42.50 [29.50, 52.50]

0.233

Smoking, n (%)

 No

15 (88.24)

27 (90.00)

6 (100.00)

5 (100.00)

–

 Yes

2 (11.76)

3 (10.00)

0 (0.00)

0 (0.00)

Drinking, n (%)

 No

16 (94.12)

29 (96.67)

6 (100.00)

5 (100.00)

–

 Yes

1 (5.88)

1 (3.33)

0 (0.00)

0 (0.00)

Oxygen therapy, n (%)

 No

3 (17.65)

3 (10.00)

1 (16.67)

1 (20.00)

1.000

 Yes

14 (82.35)

27 (90.00)

5 (83.33)

4 (80.00)

RBC count (× 10⁹/L)

4.01 [3.80, 4.43]

3.93 [3.45, 4.28]

4.10 [3.67, 4.45]

4.49 [4.22, 4.67]

0.465

Albumin (g/L)

37.91 (2.59)

36.46 (3.29)

36.23 (3.16)

36.80 (2.12)

0.763

Globulin (g/L)

29.19 (5.29)

30.02 (4.57)

29.27 (5.04)

29.63 (4.47)

0.911

The percentage decline rates of consolidation volume to whole lung volume on CT from pre-MSC treatment to 28 days

− 21.72 [− 41.21, − 10.13]

− 71.61 [− 87.51, − 62.34]

− 27.91 [− 37.96, 34.11]

− 81.12 [− 96.37, − 75.40]