ABSTRACT
Diseases of the airway are common and make up a significant proportion of the respiratory
physician's workload. The major contributors to this situation, such as asthma, chronic
obstructive pulmonary disease (COPD), and chronic cough, all result from airway inflammation
and often have an overlapping clinical picture, which in some instances makes accurate
clinical diagnosis difficult. Asthma is a condition characterized by variable airflow
obstruction, airway hyper-responsiveness, and airway inflammation, which is usually
eosinophilic. However, the relationship between eosinophilic inflammation and asthma
is complex, with only a weak correlation between the severity of airway inflammation
and the markers of the severity of asthma, such as Pc20 and FEV1. Eosinophilic bronchitis
is characterized by a chronic cough and sputum eosinophilia without airway hyper-responsiveness
or variable airflow obstruction. The asthma phenotype is characterized by microlocalization
of mast cells in the airway smooth muscle, emphasizing the importance of airway smooth
muscle dysfunction in asthma. COPD has generally been considered to be a neutrophilic
disease, in contrast to asthma. However, there is increasing evidence that a significant
subgroup exists consisting of patients with stable COPD who have chronic airway eosinophilia
with a more steroid-responsive disease. This article covers the role of eosinophils
in the airway disorders asthma, COPD, and eosinophilic bronchitis.
KEYWORDS
Inflammation - eosinophils - asthma - chronic obstructive airways disease - eosinophilic
bronchitis
REFERENCES
- 1
Pavord I D, Pizzichini M M, Pizzichini E, Hargreave F E.
The use of induced sputum to investigate airway inflammation.
Thorax.
1997;
52
498-501
- 2
Green R H, Brightling C E, McKenna S et al..
Asthma exacerbations and sputum eosinophil counts: a randomised controlled trial.
Lancet.
2002;
360
1715-1721
- 3
Gleich G J.
Mechanisms of eosinophil-associated inflammation.
J Allergy Clin Immunol.
2000;
105
651-663
- 4
Tavernier J, Van der H J, Verhee A et al..
Interleukin 5 regulates the isoform expression of its own receptor alpha-subunit.
Blood.
2000;
95
1600-1607
- 5 Spry C JF.
The natural history of eosinophils. In: Smith H, Cook RM The immunopharmacology of eosinophils. London; Academic Press
1993: 1-9
- 6
Kay A B.
T cells as orchestrators of the asthmatic response.
Ciba Found Symp.
1997;
206
56-67
- 7
Leckie M J, Brinke A T, Khan J et al..
Effects of an interleukin-5 blocking monoclonal antibody on eosinophils, airway hyper-responsiveness,
and the late asthmatic response.
Lancet.
2000;
356
2144-2148
- 8
Domachowske J B, Bonville C A, Easton A J, Rosenberg H F.
Pulmonary eosinophilia in mice devoid of interleukin-5.
J Leukoc Biol.
2002;
71
966-972
- 9
Giembycz M A, Lindsay M A.
Pharmacology of the eosinophil.
Pharmacol Rev.
1999;
51
213-340
- 10
Wardlaw A J.
Molecular basis for selective eosinophil trafficking in asthma: a multistep paradigm.
J Allergy Clin Immunol.
1999;
104
917-926
- 11
Bochner B S.
Road signs guiding leukocytes along the inflammation superhighway.
J Allergy Clin Immunol.
2000;
106
817-828
- 12
Kita H, Weiler D A, bu-Ghazaleh R, Sanderson C J, Gleich G J.
Release of granule proteins from eosinophils cultured with IL-5.
J Immunol.
1992;
149
629-635
- 13
Nicklas R A.
National and international guidelines for the diagnosis and treatment of asthma.
Curr Opin Pulm Med.
1997;
3
51-55
- 14
Sidebotham H J, Roche W R.
Asthma deaths; persistent and preventable mortality.
Histopathology.
2003;
43
105-117
- 15
Chapman I D, Foster A, Morley J.
The relationship between inflammation and hyperreactivity of the airways in asthma.
Clin Exp Allergy.
1993;
23
168-171
- 16
Wardlaw A J, Brightling C, Green R, Woltmann G, Pavord I.
Eosinophils in asthma and other allergic diseases.
Br Med Bull.
2000;
56
985-1003
- 17
Green R H, Brightling C E, Woltmann G, Parker D, Wardlaw A J, Pavord I D.
Analysis of induced sputum in adults with asthma: identification of subgroup with
isolated sputum neutrophilia and poor response to inhaled corticosteroids.
Thorax.
2002;
57
875-879
- 18
Flood-Page P T, Menzies-Gow A N, Kay A B, Robinson D S.
Eosinophil's role remains uncertain as anti-interleukin-5 only partially depletes
numbers in asthmatic airway.
Am J Respir Crit Care Med.
2003;
167
199-204
- 19
Wenzel S E, Schwartz L B, Langmack E L et al..
Evidence that severe asthma can be divided pathologically into two inflammatory subtypes
with distinct physiologic and clinical characteristics.
Am J Respir Crit Care Med.
1999;
160
1001-1008
- 20
Gibson P G, Simpson J L, Saltos N.
Heterogeneity of airway inflammation in persistent asthma: evidence of neutrophilic
inflammation and increased sputum interleukin-8.
Chest.
2001;
119
1329-1336
- 21
Brightling C E, Monteiro W, Ward R et al..
Sputum eosinophilia and short-term response to prednisolone in chronic obstructive
pulmonary disease: a randomised controlled trial.
Lancet.
2000;
356
1480-1485
- 22
Gibson P G, Dolovich J, Denburg J, Ramsdale E H, Hargreave F E.
Chronic cough: eosinophilic bronchitis without asthma.
Lancet.
1989;
1
1346-1348
- 23
Brightling C E, Ward R, Goh K L, Wardlaw A J, Pavord I D.
Eosinophilic bronchitis is an important cause of chronic cough.
Am J Respir Crit Care Med.
1999;
160
406-410
- 24
Berry M A, Hargadon B, McKenna S et al..
Observational study of the natural history of eosinophilic bronchitis.
Clin Exp Allergy.
2005;
35
598-601
- 25
Brightling C E, Bradding P, Symon F A, Holgate S T, Wardlaw A J, Pavord I D.
Mast-cell infiltration of airway smooth muscle in asthma.
N Engl J Med.
2002;
346
1699-1705
- 26
Brightling C E, Symon F A, Birring S S, Bradding P, Pavord I D, Wardlaw A J.
TH2 cytokine expression in bronchoalveolar lavage fluid T lymphocytes and bronchial
submucosa is a feature of asthma and eosinophilic bronchitis.
J Allergy Clin Immunol.
2002;
110
899-905
- 27
Ronchi M C, Piragino C, Rosi E, Amendola M, Duranti R, Scano G.
Role of sputum differential cell count in detecting airway inflammation in patients
with chronic bronchial asthma or COPD.
Thorax.
1996;
51
1000-1004
- 28
Balzano G, Stefanelli F, Iorio C et al..
Eosinophilic inflammation in stable chronic obstructive pulmonary disease. Relationship
with neutrophils and airway function.
Am J Respir Crit Care Med.
1999;
160
1486-1492
- 29
Jeffery P K.
Differences and similarities between chronic obstructive pulmonary disease and asthma.
Clin Exp Allergy.
1999;
29(Suppl 2)
14-26
- 30
Saetta M, Di S A, Maestrelli P et al..
Airway eosinophilia and expression of interleukin-5 protein in asthma and in exacerbations
of chronic bronchitis.
Clin Exp Allergy.
1996;
26
766-774
- 31
Papi A, Romagnoli M, Baraldo S et al..
Partial reversibility of airflow limitation and increased exhaled NO and sputum eosinophilia
in chronic obstructive pulmonary disease.
Am J Respir Crit Care Med.
2000;
162
1773-1777
- 32
Dippolito R, Foresi A, Chetta A et al..
Eosinophils in induced sputum from asymptomatic smokers with normal lung function.
Respir Med.
2001;
95
969-974
- 33
Saetta M, Di S A, Maestrelli P et al..
Airway eosinophilia in chronic bronchitis during exacerbations.
Am J Respir Crit Care Med.
1994;
150
1646-1652
- 34
Saetta M, Di S A, Turato G et al..
CD8+ T-lymphocytes in peripheral airways of smokers with chronic obstructive pulmonary
disease.
Am J Respir Crit Care Med.
1998;
157
822-826
- 35
Lams B E, Sousa A R, Rees P J, Lee T H.
Immunopathology of the small-airway submucosa in smokers with and without chronic
obstructive pulmonary disease.
Am J Respir Crit Care Med.
1998;
158
1518-1523
- 36
Sutherland E R, Allmers H, Ayas N T, Venn A J, Martin R J.
Inhaled corticosteroids reduce the progression of airflow limitation in chronic obstructive
pulmonary disease: a meta-analysis.
Thorax.
2003;
58
937-941
- 37
Fujimoto K, Kubo K, Yamamoto H, Yamaguchi S, Matsuzawa Y.
Eosinophilic inflammation in the airway is related to glucocorticoid reversibility
in patients with pulmonary emphysema.
Chest.
1999;
115
697-702
- 38
Brightling C E, McKenna S, Hargadon B et al..
Sputum eosinophilia and the short term response to inhaled mometasone in chronic obstructive
pulmonary disease.
Thorax.
2005;
60
193-198
Andrew J WardlawPh.D.
Institute for Lung Health, Glenfield Hospital
Groby Road, Leicester LE3 9QP, UK
Email: aw24@le.ac.uk
