First author [ref.] | Aliquot fraction analysed | Group 1 | Group 2 | PMN cell counts ×10^{3} cells·mL^{−1}, unless otherwise stated | PMN cells % | Neutrophil elastase | IL-6 ×10^{3}·mL^{−1}, unless otherwise stated | IL-8 ×10^{3}·mL^{−1}, unless otherwise stated | Statistical tests | Data presentation | ||

Subjects n | Age | Subjects n | Age | |||||||||

Sly [9] | F (microbiology), P (aliquots 2 and 3) | 48 asymptomatic | Infants | 9 symptomatic | Infants | ns | Group 1 14.5 (9.0–27.1) versus Group 2 39.7 (28.3–65.0)^{#} | Group 1 100 (100–143) ng·mL^{−1} versus Group 2 100 (100–2025) ng·mL^{−1#} | ns | Independent t-tests | Median (IQR) | |

Sly [9] | F (microbiology), P (aliquots 2 and 3) | 45 uninfected | Infants | 12 infected | Infants | Group 1 31.3 (11.3–76.3) versus Group 2 169 (72.2–208.5)^{#} | Group 1 13.5 (8.3–26.1) versus Group 2 35.7 (25.3–44.7)^{¶} | Group 1 100 (100–100) ng·mL^{−1} versus Group 2 350 (100–1330) ng·mL^{−1+} | Group 1 260 (128–630) pg·mL^{−1} versus Group 2 770 (420–2120) pg·mL^{−1§} | Independent t-tests | Median (IQR) | |

Armstrong [13] | svBAL, P | 18 infected | 2.6±1.1 months | 10 noninfected, nonsymptomatic | 2.6±1.1 months | Group 1 153 (52–449) versus Group 2 15 (8–29)*** | Group 1 78 (52–94)% versus Group 2 0 (0–31)%*** | Group 1 1112 (582–2126) versus Group 2 24 (9–63)*** | Independent t-test | Mean (95% CI) | ||

Sly [9] | F (microbiology), P (aliquots 2 and 3) | 24 no antistaphylococcal prophylaxis | 3.6 (3.4–4.8) months | 33 antistaphylococcal prophylaxis | 3.6 (2.8–4.7) months | ns | ns | ns | ns | Independent t-tests | ||

Armstrong [26] | F | 28 infected | Infants (age not reported) | 7 pristine 17 uninfected | Infants (age not reported) | Group 1 11 (8.7–13) pg·mL^{−1} versus Group 2 pristine 2.2 (0.48–10) pg·mL^{−1} and uninfected 2.2 (1.8–2.6) pg·mL^{−1}*** | Wald test | Geometric mean (95% CI) | ||||

Armstrong [26] | F | 50 infected | 13 pristine | Group 1 562 (407–777) versus Group 2 pristine 127 (76–210) and uninfected 106 (67–168)*** | Group 1 50 (39–65) versus Group 2 pristine 8.4 (5.2–14) and uninfected 7.1 (4.4–12)*** | Group 1 80 (66–90)% versus Group 2 pristine 0 (0–25)% and uninfected 20 (6–44)% of patients with free NE activity*** | Group 1 1153 (754–1762) pg·mL^{−1} versus Group 2 pristine 32 (15–72) pg·mL^{−1} and uninfected 49 (23–101) pg·mL^{−1}*** | Wald test | Geometric mean (95% CI) | |||

Rosenfeld [52] | Not specified | 31 (≥10^{5} CFU·mL^{−1}) | ≤15 months at study entry | 29 (<10^{5} CFU·mL^{−1}) | ≤15 months at study entry | ns | ns | Generalised estimating equation | ||||

Rosenfeld [52] | Not specified | 31 (≥10^{5} CFU·mL^{−1}) | ≤15 months at study entry | 30 no pathogen | ≤15 months at study entry | Group 1 1145 (580–2264) versus Group 2 114 (63–206)*** | Group 1 1802 (1104–2942) versus Group 2 427 (269–679)^{ƒ¶} | Generalised estimating equation | Geometric mean (95% CI) | |||

Rosenfeld [52] | Not specified | Not specified P. aeruginosa positive | ≤15 months at study entry | Not specified other pathogen | ≤15 months at study entry | ns | Generalised estimating equation | |||||

Nixon [53] | F | 20 symptomatic | 20.7±10.6 months | 34 asymptomatic | 15.7±9.7 months | ns | ns | ns | Generalised estimating equation | |||

Nixon [53] | F | 15 infected | 22.8±6.7 months | 39 uninfected | 15.9±10.9 months | Group 1 59 (47–70) versus Group 2 28 (21–35) *** | ns | Group 1 641 (305–1350) versus Group 2 253 (158–406)^{##¶} | Generalised estimating equation | Mean and geometric mean (95% CI) | ||

Dakin [54] | F | 8 infected | 23 months | 14 uninfected | 23 months | 90.8% >10^{5} pathogens versus 24.1% <10^{5} pathogens^{¶¶} | 4600 pg·mL^{−1} >10^{5} pathogens versus 1627 pg·mL^{−1} <10^{5} pathogens^{++} | Independent t-test/ANOVA | ||||

Brennan [30] | F (microbiology), P (aliquots 2 and 3) | 9 infected | 1.55 (1.11–2.51) years | 15 uninfected | 1.58 (1.12–2.91) years | 667 (58–5342) infected versus 60 (39–91) noninfected^{ƒ} | 52 (38–81)% infected versus 17.3 (9–29)% noninfected*** | ns | Not reported | Median (IQR) | ||

Gutierrez [55] | F | 6 (≥10^{5} CFU·mL^{−1}) | 35.3±21.3 months | 24 (<10^{5} CFU·mL^{−1}) | 22.1±13.3 months | *** (right middle lobe) ns (lingula) | ^{§§} (right middle lobe)^{¶¶} (lingula) | Independent t-test | ||||

Armstrong [39] | F | 5 virus-infected | 6.5±5.3 months | 22 noninfected | 2.6±1.5 months | 169 (16, 1809) virus infected versus 16 (8, 34) noninfected*** | 1372 (561, 3358) virus-infected versus 47 (21, 108) noninfected*** | ANCOVA | Geometric mean (95% CI) | |||

Brennan [30] | F (microbiology), P (aliquots 2 and 3) | 14 asymptomatic | <6 years | 11 symptomatic | <6 years | Group 1 60.3 (38.45–90.55) versus Group 2 667.58 (64.3–5341.48)^{ƒƒ,¶} | Group 1 16.5 (10.5–26.5) versus Group 2 53 (49.67–80.5)*** | ns | Not reported | Median (IQR) | ||

Sagel [56] | P | 59 P. aeruginosa positive | 6 months–6 years | 31 no pathogens | 6 months–6 years | Group 1 5.6±0.7 log_{10}·mL^{−1} versus Group 2 4.8±0.6 log_{10}·mL^{−1}*** | Group 1 49.3±25.9 versus Group 2 22.1±14.4*** | Group 1 41% of patients versus Group 2 0% of patients with NE detected in BAL*** | ns | Group 1 3.1±0.6 pg·mL^{−1} versus Group 2 2.3±0.6 pg·mL^{−1}*** | Linear regression | Mean±sd |

Sagel [56] | P | 21 P. aeruginosa negative, other pathogen present | 6 months–6 years | 31 no pathogens | 6 months–6 years | Group 1 59±0.3 log_{10}·mL^{−1} versus Group 2 5.6±0.3 log_{10}·mL^{−1}*** | Group 1 33.6±17.6 versus Group 2 22.1±14.4* | ns | ns | Group 1 2.8±0.7 pg·mL^{−1} versus Group 2 2.3±0.6 pg·mL^{−1}** | Linear regression | Mean±sd |

Sagel [56] | P | 59 P. aeruginosa positive | 6 months–6 years | 21 P. aeruginosa negative, other pathogen present | 6 months–6 years | ns | Group 1 33.6±17.6 versus Group 2 22.1±14.4^{+} | ns | ns | ns | Linear regression | Mean±sd |

Sagel [57] | P | 44 nonmucoid P. aeruginosa | 6 months–6 years | 15 mucoid P. aeruginosa | 6 months–6 years | Group 1 5.9±0.6 log_{10}·mL^{−1} versus 5.5±0.7 log_{10}·mL^{−1#} | Group 1 62.7±22.1 versus Group 2 44.5±25.7^{###} | ns | ns | ns | Linear regression | Mean±sd |

Sagel [56] | P | Not specified S. aureus present | 6 months–6 years | Not specified S. aureus not present | 6 months–6 years | *** | ^{¶¶¶} | ^{+} | *** | Linear regression | Values not reported | |

Hilliard [45] | P | 31 exacerbation | 6.2 years | 12 clinically well | 6.2 years | Group 1 1.0×10^{6}·mL^{−1} versus Group 2 0.4×10^{6}·mL^{−1}* | Nonparametric tests | Median | ||||

Muhlebach [41] | Not specified | Not specified P. aeruginosa positive | Mean 7.6 years | Not specified other pathogen | Mean 1.9 years | ns | ns | Independent t-test | ||||

Armstrong [15] | Not specified | 14 infected | Children (age not reported) | 20 noninfected | Children (age not reported) | Group 1 259 (70–968)×10^{6}·L^{−1} versus 17 (8–36)×10^{6}·L^{−1}*** | Group 1 2013 (1164–3784) ng·L^{−1} versus Group 2 26 (13–51) ng·L^{−1}*** | Independent t-test | Mean (95% CI) | |||

Noah [43] | P | 15 infected | <13 years | 10 uninfected | <13 years | Group 1 3358 (100–11 520) versus Group 2 291 (25–952)* | Group 1 84 (16–96) versus Group 2 40 (4–62)* | ns | ns | Kruskal–Wallis | Median (range) | |

Regamey [28] | P | 36 during exacerbation | 10 stable | Group 1 970 (287–1584) versus Group 2 222 (21–380)^{¶¶¶} | Independent t-test | Median (IQR) | ||||||

Regamey [28] | P | 13 Aspergillus present | 13 Aspergillus not present | ns | Independent t-test | |||||||

Regamey [28] | P | 11 P. aeruginosa positive | 15 P. aeruginosa negative | ns | Independent t-test | |||||||

Bonfeld [33] | P | 17 P. aeruginosa positive | Adolescents and adults (age not reported) | 5 P. aeruginosa negative | Adolescents and adults (age not reported) | ns | Kruskal–Wallis | |||||

Kirchner [40] | P | 7 older patients | Mean (range) 18.6 (13.5–31) years | 16 younger patients | Mean (range) 10.5 (2–25) months | ns | Kruskal–Wallis |

Biomarkers are present at higher levels in patients with more severe lung disease. All samples are BAL, unless otherwise stated. PMN: polymorphonuclear; IL: interleukin; F: first; P: pooled; svBAL: small volume BAL; IQR: interquartile range; ns: not significant;

*P. aeruginosa*:*Pseudomonas aeruginosa*;*S. aureus*:*Staphylococcus aureus*; NE: neutrophil elastase. *: p<0.05; **: p<0.01; ***: p<0.001;^{#}: p=0.0001;^{¶}: p=0.027;^{+}: p=0.003;^{§}: p=0.036;^{ƒ}: p=0.04;^{##}: p=0.03;^{¶¶}: p=0.01;^{++}: p=0.0001;^{§§}: p=0.05;^{ƒƒ}: p= 0.002;^{###}: p=0.02;^{¶¶¶}: p=0.004.