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Table 2 Results of the systematic review

From: Neutrophil elastase in bronchiectasis

Author and year

Study design

Setting

Clinical stability

Sample size

Assay manufacturer (methods)

Quantitative findings

Biological matrix

Major results

Stockley, 1984 [18]

Cross-sectional

Monocentric, outpatients

Stable state

Exacerbation

34 Bx patients

Elastin-agarose diffusion plate (in-home assay)

NE activity (μg x mL): grade1 19.5; grade2 48.2; grade3 62.9

Sputum

Correlation with sputum macroscopic appearance

Smallman, 1984 [6]

Cross-sectional/Prospective

Monocentric, outpatients

Stable state

8 Bx patients

Elastin-agarose diffusion plate (in-home assay)

NE activity (μg x mL): not quantified but evaluated as present/not present (lower limit of detection 0.8)

Sputum

Inverse correlation with ciliary beat frequency

NE reduction after short-term antibiotic therapy

Fujita, 1992 [60]

Cross-sectional

Monocentric, outpatients

Stable state

9 Bx patients in a cohort of 64 chronic respiratory diseases +15 healthy subjects

Elisa for NE- A1AT complex (in-home assay)

NE-A1AT complex levels (μg x L): 558 ± 198; healthy subjects 122 ± 4

Blood

NE- A1AT complex higher in Bx patients than in healthy subjects

Lloberes, 1992 [63]

Cross- sectional

Monocentric, outpatients

Stable state

26 Bx patients

Elastin-agarose diffusion plate (in-home assay)

NE activity (μg × 100 μL): purulent 7.75 (0–21.5); mucopurulent 1.3 (0–19.5); mucoid 0

Sputum

Correlation with sputum macroscopic appearance

Ip, 1993 [71]

Prospective

Monocentric, outpatients

Exacerbation

12 Bx patients

Spectrophotometry, SLAPN substrate

NE activity (mU × 100 μL): baseline 50.5 ± 17.1; exacerbation before atb 51.8 ± 25.4; 1-week atb −24.3 ± 20.7; 2-week atb −35.1 ± 17.8; 2-week after atb −12.1 ± 35.6; 6-week after atb −32.8 ± 26.8

Sputum

NE reduction after short-term antibiotic therapy

Llewellyn-Jones, 1995 [15]

Prospective

Monocentric, outpatients

Stable state

9 Bx patients +8 healthy subjects

Fluorescence (in-home assay)

NE activity (μg x mL−1): day -7th 4.0 ± 0.46; baseline 4.15 ± 0.69; day 14th 4.25 ± 0.63; day 28th 4.39 ± 0.65; day 63th 4.03 ± 0.67

Blood

No NE reduction after indomethacin

Sepper, 1995 [74]

Cross-sectional

Monocentric, outpatients

Stable state

24 Bx patients +15 healthy subjects

Spectrophotometry, SAAVNA substrate

NE activity (mU x g): mild group 0.21 ± 0.09; moderate group 1.87 ± 1.12; severe group 2.64 ± 1.63; healthy subjects 0.09 ± 0.03

BAL

Correlation with symptoms, exacerbation rate and radiological severity

Nakamura, 1997 [56]

Cross-sectional

Monocentric, outpatients

Stable state

3 Bx patients in a cohort of 8 chronic respiratory diseases +15 healthy subjects

Elisa (in-home assay)

Quantitative findings only reported as figures

BAL

NE higher in Bx than in healthy subjects

Gaga, 1998 [57]

Cross-sectional

Monocentric, outpatients

Stable state

12 Bx patients +11 healthy subjects

Immunocitochemistry (in-home assay)

Neutrophils (cells x mm3): Bx patients 114; healthy subjects 41

Bronchial biopsies

NE higher in Bx than in healthy subjects

Nakamura, 1999 [78]

Prospective

Monocentric, outpatients

Stable state

3 Bx patients in a cohort of 10 chronic respiratory diseases

Elisa (in-home assay)

NE levels (μg x mL−1): baseline 125.5 ± 47.5; 16.8 ± 7.1 after atb

BAL

Ne reduction after 3-month roxithromycin

Ichikawa, 1999 [64]

Cross-sectional

Monocentric, outpatients

Stable state

18 Bx patients in a cohort of 59 chronic respiratory diseases +28 healthy subjects

Spectrofluorometry AMC substrate

NE activity (U): purulent 1239.2 ± 1017.8; mucoid 45.7 ± 115.1

Sputum

Inverse correlation with IgBF levels and sputum purulence

Hill, 2000 [16]

Cross- sectional

Monocentric, outpatients

Stable state

43 Bx patients in a cohort of 160 chronic respiratory diseases

Spectrophotometry

NE levels (nM): mixed flora 0 (0–20); high bacterial load 21 (4–40)

Sputum

Correlation with sputum bacterial load

Schaaf, 2000 [68]

Cross-sectional

Monocentric, outpatients

Stable state

11 Bx patients in a cohort of 66 chronic respiratory diseases +12 healthy subjects

Immunoluminometry

Colorimetry

NE-A1AT complex levels (ng x mL): Bx patients 44 (15–152); healthy subjects 3 (0–15)

BAL

NE higher in Bx than in healthy subjects

Correlation with P. aeruginosa chronic respiratory infection

Tsang, 2000 [75]

Cross-sectional

Monocentric, outpatients

Stable state

30 Bx patients

Spectrophotometry, SAAVNA substrate

NE levels (U x mL): 6.60 ± 3.13

Sputum

Correlation with 24 h sputum volume, sputum inflammatory markers (leukocytes, IL-B and TNFa), radiological severity and spirometry (FEV1, FVC)

Zheng, 2000 [69]

Cross-sectional

Monocentric, outpatients

Stable state

35 Bx patients +18 healthy subjects

Spectrophotometry, SAAVNA substrate

NE levels (Unit x mL−1): P. aeruginosa 222.6 (18.3–267.5); 8.7 (0.6–186.7)

Sputum

Correlation with P. aeruginosa chronic respiratory infection

Viglio, 2000 [21]

Cross-sectional

Monocentric, outpatients

Stable state

13 Bx patients in a cohort of 54 chronic respiratory diseases +24 healthy subjects

HPCE

DES (μg x g creatinine−1): Bx patients 23.39 ± 2.05; CF 23.39 ± 2.02; A1AT deficiency 22.3 ± 7.74; exacerbated COPD 17.15 ± 3.42; stable COPD 14.17 ± 2.33; smokers 11.97 ± 2.75; healthy subjects 9.31 ± 2.75

Urine

Desmosine higher in stable Bx than in other chronic respiratory disease and healthy subjects

Angrill, 2001 [62]

Cross-sectional

Monocentric, outpatients

Stable state

49 Bx patients +9 healthy subjects

Immunoassay (?)

NE levels (μg x L): colonized patients 231 (15–2930); not colonized patients 45 (8–2280); healthy subjects 34 (9–44)

BAL

NE higher in Bx than in healthy subjects

Correlation with neutrophils, IL8 and TNFa in BALF

Correlation with bacterial chronic respiratory infection.

Stockley, 2001 [65]

Cross-sectional

Monocentric, outpatients

Stable state

14 Bx patients +9 smokers

Spectrophotometry, MSAPN substrate

Elisa (in-home assay)

NE levels (μM): sputum colour value-3 0.006 ± 1.0; sputum colour value-7 4.14 ± 1.0

Sputum

Correlation with sputum macroscopic appearance

Correlation with MPO and 24 h sputum volume

Inverse correlation with A1AT

Zheng, 2001 [59]

Cross-sectional

Monocentric, outpatients

Stable state

14 Bx patients +15 healthy subjects

Anti-NE antibodies

Median neutrophils x mm−2: Bx patients 608 (101–1013); healthy subj. 127 (24–630)

Endobronchial biopsies

NE higher in bronchiectatic lamina propria than in healthy subjects

Vandivier, 2002 [58]

Prospective

Monocentric, outpatients

Exacerbation

6 Bx patients in a cohort of 18 chronic respiratory diseases

Spectrophotometry

NE (U x mL): Bx patients 10; CF 3

Sputum

NE higher in Bx

NE as cause of delay in apoptotic cell clearance

Chan, 2003 [12]

Cross-sectional

Monocentric, outpatients

Stable state

10 Bx patients

Spectrophotometry

NE activity range (mM): 0.9–1.2

Sputum

NE not only as free but complexed with polyanionic partners (syndecan-1) and A1AT

Watt, 2004 [72]

Prospective

Monocentric, outpatients

Exacerbation

15 Bx patients +10 healthy subjects

Kinetic assays (?)

NE levels (ng x mL): after atb −73,451 (135,495–12,303)

Sputum

NE reduction after short-term antibiotic therapy

Chan, 2009 [61]

Cross-sectional

Monocentric, outpatients

Stable state

12 Bx patients

Spectrophotometry, MSAPN substrate

ELISA (in-home assay)

NE activity (mM): 1.3 (1–2)

Sputum

NE complexed with syndecan-1

Description of protease/anti-protease balance

Murray, 2010 [77]

RCT

Monocentric, outpatients

Stable state

65 Bx patients

Elastin-agarose diffusion plate (in-home assay)

NE activity gentamicin group vs placebo: (U x mg): baseline 3.6 (0–17.6) vs 4.1 (0–19); 3-month 0 (0–0) vs 0 (0–20.4); 6-month 0 (0–2.9) vs 0 (0–29.1); 9-month 0 (0–7.6) vs 0.9 (0–19.4); 12- month 0 (0–1.8) vs 1.8 (0.17–16); 15-month 7.1 (0–56) vs 2.8 (0.9–18.2)

Sputum

NE reduction after 3-month inhaled gentamicin

Chalmers, 2012 [67]

Prospective

Monocentric, outpatients

Stable state

Exacerbation

385 Bx patients

Elastin-agarose diffusion plate (in-home assay)

NE activity (μg x mL): P. aeruginosa infected 4.9 (1.2–68); P. aeruginosa not infected 1.2 (0.4–147.2); other quantitative findings only reported as figures

Sputum

Correlation with bacterial load and radiological severity

Mandall, 2013 [73]

Prospective

Monocentric, outpatients

Stable state

163 Bx patients

Spectrophotometry

NE activity (U x mL): GERD group 5; non-GERD group 3

Sputum

Correlation with GERD

Stockley, 2013 [55]

RCT

Multicentric, outpatients

Stable state

38 Bx patients

Custom-made immunoassay (in-home assay) for both NE and desmosine

NE activity AZD9668 group vs placebo (μM x L): baseline 24.54 vs 7.28; end of treatment 15.92 vs 7.49

Sputum

Urine

NE reduction after 28-day of oral AZD9668

No difference in desmosine between AZD9668 and placebo

Goeminne, 2014 [66]

Cross-sectional

Monocentric, outpatients

Stable state

49 Bx patients +12 healthy subjects

Enzymatic assay

NE activity (μg x mL): Bx patients 15 (3–23); healthy subject 0.8 (0.4–1.2)

Sputum

Correlation with TNFA, CXCL8 and MMP-9

Inverse correlation with FVC

Liu, 2014 [14]

RCT

Monocentric, outpatients

Stable state

43 Bx patients

ELISA (in-home assay)

Quantitative findings only reported as figures

Sputum

NE reduction after 6-month roxythromicin

Aliberti, 2016 [70]

Prospective

Multicentric, outpatients

Stable state

1145 Bx patients

different assays according to different centers

Quantitative findings only reported as figures

Sputum

Correlation with ‘P. aeruginosa‘cluster and ‘Other chronic infection’ cluster

Chalmers, 2016 [17]

Prospective

 

Stable state

Exacerbation

381 Bx patients

Immunoassay (ProAxsis LTD) Kinetic assay (Sigma Aldrich)

LC-MS for desmosine

NE levels (μg x mL): baseline 0.39 (0–23.5); onset of exacerbation 57.0 (3.3–145); after 14-day atb 0 (0–125.8); 1-month later 1.3 (0–29.9)

Sputum

Serum

Correlation with BSI, MRC, FEV 1 , bacterial load, radiological severity

Correlation with higher exacerbation rate, FEV1 decline, all-cause mortality during 3-year follow up

NE increase during exacerbations and NE reduction after short-term antibiotic therapy

Serum desmosine is associated with age and disease severity

  1. Definitions: atb antibiotics, A1AT alpha-1 anti-trypsin, BAL broncho-alveolar lavage, Bx bronchiectasis, DES desmosine, NE neutrophil elastase, SLAPN succinyl-trialanine-nitroanilide, SAAVNA succinyl-Ala-Ala-Val-nitroanilide, MSAPN methoxysuccinyl-Ala-Ala-Pro-Val-paranitroanilide, HPCE high-performance capillary electrophoresis, LC-MS liquid chromatography-mass spectrometry