Airway inflammation in asthma and perennial allergic rhinitis. Relationship with nonspecific bronchial responsiveness and maximal airway narrowing.
BACKGROUND
Eosinophilic airway inflammation is the hallmark of asthma, but it has also been reported in other conditions such as allergic rhinitis. We have tested whether the analysis of cells and chemicals in sputum can distinguish between patients with mild allergic asthma, those with allergic rhinitis, and healthy controls. The relationship between inflammation markers in sputum and nonspecific bronchial hyperresponsiveness to methacholine (BHR) (PD20 and maximal response plateau [MRP] values) was also evaluated.


METHODS
We selected 31 mild asthmatics and 15 rhinitis patients sensitized to house-dust mite. As a control group, we studied 10 healthy subjects. Every subject underwent the methacholine bronchial provocation test (M-BPT) and sputum induction. Blood eosinophils and serum ECP levels were measured. Sputum cell differentials were assessed, and eosinophil cationic protein (ECP), tryptase, albumin, and interleukin (IL)-5 levels were measured in the entire sputum supernatant.


RESULTS
Blood eosinophils and serum ECP levels were higher in asthma patients and rhinitis than in healthy controls, but no difference between asthma patients and rhinitis patients was found. Asthmatics had higher eosinophil counts and higher ECP and tryptase levels in sputum than rhinitis patients or control subjects. Sputum albumin levels were higher in asthmatics than in controls. Rhinitis patients exhibited higher sputum eosinophils than healthy controls. An association between sputum eosinophil numbers and MPR values (r= -0.57) was detected, and a trend toward correlation between sputum ECP levels and PD20 values (r= -0.47) was found in the rhinitis group, but not in asthmatics. No correlation between blood eosinophilic inflammation and lung functional indices was found.


CONCLUSIONS
Induced sputum is an accurate method to study bronchial inflammation, allowing one to distinguish between rhinitis patients and mildly asthmatic patients. The fact that no relationship was detected between sputum inflammation and BHR suggests that other factors, such as airway remodeling, may be at least partly responsible for BHR in asthma.
Alvarez
M J
MJ
Servicio de Alergología, Hospital Virgen del Camino, Pamplona, Spain.
Olaguibel
J M
JM
García
B E
BE
Rodríquez
A
A
Tabar
A I
AI
Urbiola
E
E
D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000009:adverse effects; D000818:Animals; D039741:Antigens, Dermatophagoides; D001249:Asthma / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology*; D001798:Blood Proteins / Q000378:metabolism; D016535:Bronchial Hyperreactivity / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology*; D001985:Bronchial Provocation Tests; D053818:Chymases; D047091:Eosinophil Granule Proteins; D004804:Eosinophils / Q000378:metabolism; D005260:Female; D006023:Glycoproteins / Q000009:adverse effects; D006801:Humans; D007073:Immunoglobulin E / Q000378:metabolism; D018836:Inflammation Mediators / Q000378:metabolism; D015848:Interleukin-5 / Q000378:metabolism; D007958:Leukocyte Count; D008297:Male; D016210:Methacholine Chloride; D008925:Mites / Q000276:immunology; D012221:Rhinitis, Allergic, Perennial / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology*; D012260:Ribonucleases; D012697:Serine Endopeptidases / Q000378:metabolism; D013183:Sputum / Q000166:cytology / Q000378:metabolism; D053802:Tryptases
D000485:Allergens; D039741:Antigens, Dermatophagoides; D001798:Blood Proteins; D047091:Eosinophil Granule Proteins; D006023:Glycoproteins; D018836:Inflammation Mediators; D015848:Interleukin-5; D016210:Methacholine Chloride; D007073:Immunoglobulin E; D012260:Ribonucleases; D012697:Serine Endopeptidases; C083294:chymase 2; D053818:Chymases; D053802:Tryptases