Valentina Gutiérrez

Peak Flow Variability and Sputum Eosinophilia in Allergic Rhinits

BACKGROUND Although some non-asthmatic subjects with allergic rhinitis exhibit airway hyperresponsiveness and increased diurnal peak expiratory flow (PEF) variation, little is known about the critical features that determine these physiologic alterations. OBJECTIVE In subjects with allergic rhinitis and methacholine hyperresponsiveness but no asthma symptoms, we examined whether there were features of asthmatic airway inflammation. METHODS Forty non-asthmatic adults (11 with allergic rhinitis and methacholine hyperresponsiveness, 20 with allergic rhinitis and normal methacholine responsiveness, and 9 healthy control subjects) were studied. Sputum was induced with inhaled hypertonic saline for 5-minute periods for up to 20 minutes. Plugs from the lower respiratory tract were selected for differential counting in cytocentrifuged preparations. For the next 14 days, subjects measured their PEF two times daily. Peak expiratory flow variation was expressed as amplitude % mean. RESULTS Peak expiratory flow variation was significantly higher in subjects with allergic rhinitis and methacholine hyperresponsiveness than in allergic rhinitis patients with normal methacholine responsiveness and healthy controls. Eosinophil counts in the induced sputum were significantly higher in the subjects with allergic rhinitis and methacholine hyperresponsiveness [median (interquartile range), 7.3 (9.0)%] compared with allergic rhinitis patients with normal methacholine responsiveness [2.5 (3.8)%, P = .03] and healthy controls [1.0 (1.0)%, P = .02]. CONCLUSION We conclude that eosinophilic inflammation may be present in subjects with allergic rhinitis and airway hyperresponsiveness even when there are no symptoms of asthma. This could indicate that bronchial eosinophilia is insufficient to cause asthmatic symptoms.

Variability of Peak Expiratory Flow Rate in Allergic Rhinitis and Mild Asthma: Relationship to Maximal Airway Narrowing

BACKGROUND Previous studies have demonstrated a significant correlation between airway sensitivity to pharmacologic agents and daily peak expiratory flow rate (PEF) variation in asthmatic and nonasthmatic subjects. OBJECTIVE The aim of this study was to investigate, both in patients with asthma and in subjects with allergic rhinitis, differences in daily PEF variation between subjects with plateau on the concentration-response curves to methacholine and those without plateau. METHODS A total of 120 adults (50 with mild asthma, 52 with allergic rhinitis, and 18 healthy control subjects) were challenged with methacholine (up to 200 mg/mL) and, for the next 14 days, measured their PEF three times daily. The response to methacholine was measured by the percent decrease in FEV1. A maximal response plateau was considered if three or more of the highest concentrations fell within a 5% response range. Diurnal PEF variation was expressed as the amplitude percent mean. RESULTS A plateau response was detected in 11 (22%) asthmatic patients, in 33 (63%) subjects with allergic rhinitis, and in 17 (94%) healthy subjects. Diurnal PEF variation was significantly greater (P < .01) in the asthmatic group without a plateau (8.8 +/- 3.7%) compared with the three groups with a plateau (asthma = 5.5 +/- 2.9%; allergic rhinitis = 4.6 +/- 2.1%; healthy = 4.7 +/- 2.3%). Those three groups with a plateau were not significantly different from each other with respect to PEF variability. Diurnal PEF variation was significantly higher in allergic rhinitis patients without plateau (7.6 +/- 3.5%) than in allergic rhinitis patients with plateau (P < .01) and healthy subjects (P < .05). The rhinitic group without a plateau, however, was not significantly different from either the asthmatic group without plateau or the asthmatic group with plateau. CONCLUSIONS We conclude that in both asthmatic patients and subjects with allergic rhinitis, the shape of the concentration-response curve to methacholine provides new information on the relationship between airway responsiveness and PEF variability. Further, allergic rhinitis subjects without evidence of plateau have a degree of diurnal PEF variation similar to that found in patients with mild asthma. This could indicate that those subjects may have subclinical inflammatory changes in the airways.

Relationship between induced sputum cell counts and fluid-phase eosinophil cationic protein and clinical or physiologic profiles in mild asthma

BACKGROUND Sputum analysis is the only non-invasive method to examine airway inflammatory processes in subjects with asthma. The aim of this study was to investigate the relationship between cell counts and fluid phase levels in induced sputum in subjects with mild asthma, and the severity of asthma as assessed by clinical, physiologic and blood measurements. METHODS Forty patients with mild asthma, aged 17 to 49 years were studied (good sputum sample only from 31). On the first day, spirometry and methacholine challenges were performed. After 2 to 4 days, venous blood for absolute eosinophil count and eosinophil cationic protein (ECP) measurement was obtained and sputum was induced by inhalation of hypertonic saline. For the next 15 days subjects recorded their peak expiratory flow (PEF), symptom scores, and beta2-agonist requirements twice daily. Differential counts of leukocytes were done on cytospin preparations of homogenized sputum and the supernatant was examined for eosinophil cationic protein (ECP). RESULTS Sputum eosinophil counts and not neutrophil, epithelial cells, macrophages, or lymphocytes, were inversely correlated to FEV1/FVC % (r = -.57, P = .0008) and to PC20-methacholine (r = -.40, P = .024). No statistical relationship was obtained between eosinophil counts and either symptom scores, bronchodilator requirements, or daily PEF variability. Sputum ECP values were correlated to FEV1/FVC% (r = -.41, P = .026) but not to PC20 (r = -.32, P = .08) or clinical scores or PEF variation. A trend to significance was appreciated between peripheral blood and sputum eosinophil counts (r = .34, P = .067) and no relationship was found between sputum and serum ECP values (r = .10, P = .38). CONCLUSIONS Although sputum markers give some information about disordered lung function and physiologic changes in the airways, they are not the only factors concerned in the clinical expression of mild asthma.