Analysis of demographic data of patients and healthy controls
Out of the 82 patients, half were men and half female, aged between 25–89 years, with an average age(60.98 ± 14.53)years. A total of 19 patients had Pseudomonas aeruginosa infection, while 30 were infected with different bacteria like, Haemophilus influenzae, Staphylococcus aureus, Escherichia coli, Streptococcus pneumoniae. and methicillin-resistant S. aureus. One of the patients was also found to be coinfected with H. influenzae and S. pneumoniae. We examined 28 healthy controls, 13 of whom were male and 15 were female, with an average age of 45.11 ± 14.80 years. Statistical analysis showed that the age and sex of patients had no significant effect on the NEUT-SFL. Baseline characteristic are shown in Table 1.
Table 1
Characteristics at Baseline
Characteristics
|
All
Patients
(n = 82)
|
Mild bronchiectasis
(n = 26)
|
Moderate bronchiectasis
(n = 24)
|
Severe bronchiectasis
(n = 32)
|
Healthy control
(n = 28)
|
BSI score system
|
|
Sex, n (%)
Man
Woman
|
41 (50)
41 (50)
|
7 (27)
19 (73)
|
14 (58)
10 (42)
|
20 (62.5)
12 (37.5)
|
13 (46)
15 (54)
|
Age, n (%)
< 50 y (0)
50 ~ 69 y (2)
70 ~ 79 y (4)
≥ 80 y (6)
|
11 (13)
50 (61)
13 (16)
8 (10)
|
5 (19)
20 (77)
1 (4)
0 (0)
|
4 (17)
13 (54)
6 (25)
1 (4)
|
2 (6)
17 (53)
6 (19)
7 (22)
|
16 (57)
11 (39)
1 (4)
0 (0)
|
BMI (kg/m2), n (%)
< 18.5 (2)
≥ 18.5 (0)
|
22 (27)
60 (73)
|
1 (4)
25 (96)
|
4 (17)
20 (83)
|
17 (53)
15 (47)
|
|
FEV1%pred, n (%)
> 80% (0)
50%~80% (1)
30%~49% (2)
< 30% (3)
|
19 (23)
42 (51)
15 (18)
6 (8)
|
16 (62)
10 (38)
0 (0)
0 (0)
|
1 (4)
15 (63)
6 (25)
2 (8)
|
2 (6)
17 (53)
9 (28)
4 (13)
|
|
Hospitalization of the last year, n (%)
Yes (5)
No (0)
|
33 (40)
49 (60)
|
0 (0)
26 (100)
|
6 (25)
18 (75)
|
27 (84)
5 (16)
|
|
Times of exacerbations in last years, n (%)
0 ~ 2 (0)
≥ 3 (2)
|
74 (90)
8 (10)
|
26 (100)
0 (0)
|
24 (100)
0 (0)
|
24 (75)
8 (25)
|
|
mMRC score, n (%)
1 ~ 3 (0)
4 (2)
5 (3)
|
70 (85)
12 (15)
0 (0)
|
26 (100)
0 (0)
0 (0)
|
22 (92)
2 (8)
0 (0)
|
22 (69)
10 (31)
0 (0)
|
|
Pseudomonas aeruginosa infection, n (%)
Yes (3)
No (0)
|
19 (23)
63 (77)
|
2 (8)
24 (92)
|
2 (8)
22 (92)
|
15 (47)
17 (53)
|
|
Other bacterial infections
n (%)
Yes (1)
No (0)
|
30 (37)
52 (63)
|
12 (46)
14 (54)
|
7 (29)
17 (71)
|
11 (34)
21 (66)
|
|
HRCT shows the number of dilatated lobes of the lung ≥ 3, n (%)
Yes (1)
No (0)
|
46 (56)
36 (44)
|
8 (31)
18 (69)
|
15 (63)
9 (37)
|
23 (72)
9 (21)
|
|
Clinical parameters
|
CRP
|
22.25 ± 42.33
|
3.40 ± 4.14
|
25.68 ± 44.97
|
34.99 ± 51.90
|
|
PCT
|
0.09 ± 0.17
|
0.03 ± 0.02
|
0.09 ± 0.18
|
0.13 ± 0.23
|
|
Neu*
|
5.20 ± 2.74
|
4.00 ± 1.41
|
4.51 ± 1.92
|
6.70 ± 3.37
|
3.56 ± 1.00
|
NEUT-SFL*
|
44.18 ± 3.44
|
43.47 ± 3.04
|
44.49 ± 3.23
|
44.53 ± 3.89
|
40.42 ± 2.26
|
Data are presented as mean ± SD except where otherwise indicated. |
Both sexuality and ages of the two groups had no significance (P = 0.83, P = 0.76, respectively). The level of neutrophil count and NEUT-SFL were statistically different between healthy controls and patients. *P༜0.01. |
BSI, bronchiectasis severity index; BMI, body mass index; FEV1% pred, the prediction of forced expiratory volume in the first second; mMRC, modified medical research council; CRP, C-reaction protein; PCT, Procalcitonin; HRCT: high resolution computed tomography; Neu, neutrophil; NEUT-SFL, neutrophil side fluorescence. |
The level of NEUT-SFL in the peripheral blood of bronchiectasis patients was higher than that of healthy controls |
The values of NEUT-SFL in the peripheral blood of bronchiectasis patients were 36.88–50.99 (average value: 44.18 ± 3.44, while the values of NEUT-SFL in healthy controls were 36.10–45.50 (average value: 40.42 ± 2.26). The level of NEUT-SFL in patients with bronchiectasis was higher than that in the healthy controls (Fig. 1A-B). |
The level of NEUT-SFL in the severe BSI scores group and the neutrophil count in the peripheral blood of patients positively correlated with their BSI scores.
When the entire group (all 82 patients) was considered, the NEUT-SFL values positively correlated to BSI scores (P=0.037, r=0.23). We also found that neutrophil count (P༜0.001, r=0.41) and CRP (P=0.022, r=0.25) both positively correlated to the BSI scores, while PCT and BSI scores were not correlated (P=0.118, r=0.21). However, when the 3 groups based on BSI score were considered individually, group with high BSI scores showed positive correlation with NEUT – SFL values (P=0.024, r=0.40); while no significant correlation was observed in low (P=0.078, r=0.35) and moderate (P=0.210, r=0.27) BSI score groups (Fig.2A-G).
Figure 2. The correlation between BSI scores and the level of NEUT-SFL, neutrophil count, CRP, and PCT. (A) NEUT-SFL in all patients (P = 0.037, r = 0.23); (B) NEUT-SFL in the low BSI group (P = 0.078, r = 0.35); (C) NEUT-SFL in the moderate BSI group (P = 0.210, r = 0.27); (D) NEUT-SFL in the high BSI group (P = 0.024, r = 0.40); (E) The correlation between the level of neutrophil count in the peripheral blood of patients with bronchiectasis and BSI scores (P < 0.001, r = 0.41); (F) The correlation between the level of CRP in the peripheral blood of patients with bronchiectasis and BSI scores (P = 0.022, r = 0.25); (G) The correlation between the level of PCT in the peripheral blood of patients with bronchiectasis and BSI scores (P = 0.118, r = 0.21) (n = 82).
Microorganisms may increase the level of NEUT-SFL in patients with bronchiectasis.
We analyzed the bronchoalveolar lavage fluid from 82 patients with bronchiectasis to estimate the nucleic acid content of respiratory pathogens. The results revealed that only 15 patients presented P. aeruginosa infection, and the average value of NEUT-SFL was 45.68. Four patients had > 2 types of bacterial infection, including P. aeruginosa, while 42 patients had no bacterial infection. The results indicated that the level of NEUT-SFL in patients with P. aeruginosa or other bacterial infection were significantly higher than that in patients with no bacterial infection (P = 0.019, P = 0.023). In addition, there were differences between P. aeruginosa infection and other bacterial infections and coinfection respectively (P = 0.021 and P = 0.026, respectively). Neither CRP nor neutrophil count correlated with the microbial species in patients with bronchiectasis (P > 0.05).
NEUT-SFL is negatively related to lung function.
NEUT-SFL in the peripheral blood of the patients with bronchiectasis negatively correlated to their lung function (P = 0.001). However, neither CRP (P = 0.229, r = 0.13) nor neutrophil count (P = 0.341, r = 0.11) correlated with their lung function (Fig. 4).