CC16 as an Inflammatory Biomarker in Induced Sputum Reflects Chronic Obstructive Pulmonary Disease (COPD) Severity

Figures & data

Figure 1 A flow chart of subject enrollment, induced sputum collection and assessment and specimen measurement.

Table 1 Demographic and Clinical Characteristics of Participants

	Enrolled Patients		p	Patients with Success Samples		p
	Mild-to-Moderate Group (n=57)	Severe-to-Very-Severe Group (n=45)		Mild-to-Moderate Group (n=26)	Severe-to-Very-Severe Group (n=28)
Sex (male) (N, %)	42 (73.7)	41 (91.10)	0.039	20 (76.92)	24 (85.71)	0.494
Age (years) ()	65.42±7.29	66.78±5.94	0.997	66.65±7.62	66.54±4.74	0.946
Symptoms (N, %)
Cough	30 (52.60)	22 (48.90)	0.842	13 (50.00)	15 (53.57)	1.000
Expectoration	37 (64.90)	34 (75.60)	0.283	17 (65.38)	24 (85.71)	0.114
Polypnea	38 (66.70)	33 (73.3)	0.520	18 (69.23)	20 (71.43)	1.000
Previous history (N, %)
Hypertension	20 (35.10)	16 (35.60)	1.000	8 (30.77)	13 (46.43)	0.275
Diabetes	8 (14.00)	4 (8.90)	0.542	4 (15.38)	3 (10.71)	0.699
Arrhythmia	6 (10.50)	4 (8.90)	0.335	2 (7.69)	4 (14.29)	0.670
Cardiac Dysfunction	2 (3.50)	0 (0.00)	0.502	0 (0.00)	0 (0.00)	/
Coronary Artery Disease	5 (8.80)	3 (6.70)	1.000	3 (11.54)	2 (7.14)	0.663
Hyperlipidemia	3 (5.30)	1 (2.20)	0.628	1 (3.85)	1 (3.57)	1.000
Other complications	15 (26.30)	9 (20.00)	0.490	7 (26.92)	6 (21.43)	0.754
SGRQ ()	25.85±17.08	35.88±18.43	0.006	25.23±17.53	40.00±17.00	0.003
mMRC (N, %)			0.084			0.081
0	19 (38.80)	7 (18.40)		10 (38.46)	4 (14.29)
1	18 (36.70)	23 (60.50)		8 (30.77)	15 (53.57)
2	8 (16.30)	7 (18.40)		5 (19.23)	6 (21.43)
3	4 (8.20)	1 (2.60)		2 (7.69)	0 (0.00)
CAT ()	17.50±5.40	19.71±6.45	0.119	18.11±5.29	19.46±7.13	0.494
FeNO [M (P25, P75)]	26 (17, 39)	22.5 (15.75, 35)	0.270	24 (17, 36.75)	19 (15, 28)	0.183
Treatments (N, %)
Mono Bronchodilator	19 (33.3)	6 (13.3)	0.022	9 (34.62)	6 (21.43)	0.366
Dual Bronchodilator	4 (7.0)	8 (17.80)	0.125	2 (7.69)	4 (14.29)	0.670
ICS+LABA/ICS+LAMA	14 (24.60)	8 (17.80)	0.473	5 (19.23)	5 (17.86)	1.000
ICS+LABA+LAMA	16 (28.10)	23 (51.10)	0.024	7 (26.92)	13 (46.43)	0.167
No Inhaled Medication	4 (7.00)	0 (00.00)	0.128	3 (11.54)	0 (0.00)	0.105
Acute Exacerbation (over the past year) (N, %)	10 (17.50)	14 (31.10)	0.158	7 (26.92)	8 (28.57)	1.000

Notes: Continuous data with a normal distribution are expressed as , while continuous data without a normal distribution are expressed as M (P25, P75).

Abbreviations: N, number; , mean ± standard deviation; M, median; SGRQ, St George’s Respiratory Questionnaire; mMRC, modified British Medical Research Council; CAT, COPD Assessment Test; FeNO, Fraction exhaled nitric oxide; ICS, inhaled corticosteroids; LABA, long-acting β-agonist; LAMA, long-acting muscarinic antagonist.

Table 2 Cell Phenotypes and mRNA of Inflammatory Biomarkers in Sputum of COPD Patients

	Mild-to-Moderate Group (n=26)	Severe-to-Very-Severe Group (n=28)	p
Inflammatory cells (%) [M (P25, P75)]
Neutrophils	70.68±23.17	76.66±19.85	0.311
Eosinophils	1.03 (0.32,2.03)	2.19 (0.77,6.97)	0.048*
Lymphocytes	4.04 (1.43,8.462)	2.23 (1.27,7.74)	0.545
Macrophage	10.22 (0.54,23.27)	2.01 (0.00,9.12)	0.073
Airway inflammatory phenotype (N, %)
Neutrophilic phenotype	12 (46.20)	10 (35.70)	0.580
Eosinophilic phenotype	2 (7.70)	3 (10.70)	1.000
Mix Granulocyte phenotype	4 (15.40)	12 (42.90)	0.038*
Paucigranuocytic phenotype	8 (30.80)	3 (10.70)	0.095
mRNA of sputum inflammatory biomarkers ()
CC16	2.37±0.66	0.59±0.13	0.013*
MMP9	1.32±0.19	3.30±0.88	0.040*
A1AR	1.52±0.24	2.65±0.49	0.027*
RON	1.88±0.36	3.90±1.21	0.068
IFNγ	1.61±0.25	2.10±0.74	0.810
LTB4R	1.53±0.27	3.36±0.90	0.028*
miR-21	1.15±0.16	1.70±0.24	0.408
miR-155	21.52±10.43	1.37±0.75	0.066

Notes: Continuous data with a normal distribution are expressed as , while continuous data without a normal distribution are expressed as M (P25, P75). *p < 0.05.

Abbreviations: N, number; M±SD, mean ± standard deviation; CC16, Club cell secretory protein-16; MMP9, Matrix metalloproteinase 9; A1AR, A1 Adenosine Receptor; RON, Recepteur d’Origine Nantais; IFNγ, Type II IFNs; LTB4R, Leukotriene B4 Receptor; miR-155, microRNA-155; miR-21 microRNA-21.

Figure 2 Differences in mRNA expression of CC16, MMP9, A1AR, RON, IFNγ, LTB4R, miR-21, and miR-155 in induced sputum cells between the mild-to-moderate group and the severe-to-very-severe group. Data are expressed as the means ± SEMs. *p<0.05, significant compared to the mild-to-moderate group.

Figure 3 Association between CC16 mRNA expression in induced sputum and FEV1%pred. The effects of age, sex and other biomarkers were controlled in a partial correlation analysis.

Table 3 Partial Correlation Between Airway Inflammation Marker mRNA Expression in Induced Sputum and the Eosinophilic Phenotype* After Adjustment for Age and Cough

	Coeff	p
CC16	−0.363	0.045
MMP9		0.152
A1AR		0.366
RON		0.485
IFNγ		0.700
LTB4R		0.394
miR-21		0.910
miR-155		0.772

Note: *Eosinophilic phenotype: a sample with ≥3% eosinophil.

Figure 4 Association between mRNA expression of CC16 in induced sputum cells and SGRQ score.