Serum Levels of Soluble IL-2R, IL-4, and Soluble FceRII in Adult Bronchial Asthma: Methods

Patients and Controls
Two groups of individuals, 77 asthmatics (32 atopic and 45 nonatopic) and 75 normal volunteers participated in this study. All asthmatic subjects met the American Thoracic Society’s definition of asthma.
Atopic asthmatics had positive wheal and flare reaction to skin prick tests using extracts of common aeroallergens and > 0.7 kU/ L specific IgE against house dust mite (Dermatophagoides pteronyssinus [Dp]). Nonatopic asthmatic subjects had a history of postinfectious onset of asthma, negative reaction to skin prick tests, and negative specific IgE against house dust mite. The atopic subjects included 19 subjects who had a history of seasonal nasal symptoms. All normal volunteers were nonatopic. buy tavist online

All the patients had mild to moderate asthma. At the time of the study, their symptoms were well controlled using appropriate therapy, including inhaled 02-agonist (77/77, 100 percent), regular inhaled corticosteroid (beclomethasone dipropionate [54/77, 70 percent]), histamine antagonist (13/77, 19 percent), and oral theophylline (58/77, 75 percent). None of the patients received any systemic corticosteroids. The lung function tests were performed within 2 months before blood sampling. The mean baseline values for FEV, percent predicted were 84.7 ± 1.5 percent. All asthmatic patients had a 20 percent decrease in FEV, (PC20) following the inhalation of < 8.0 mg of histamine per milliliter and had reversibility of bronchoconstriction after inhalation of salbutamol. The mean PC20 was 1.1 ± 0.1 mg/ml. There were no significant differences among treatments, the baseline values for FEV, percent predicted, and PC20 for the two asthmatic groups (see Table 1 for details). ssaying for siL-2R, IL-4, and sFceRII
To measure the serum levels of sIL-2R, IL-4, and sFceRII, an enzyme-linked immunosorbent assay (ELISA) was used.
The kit for sIL-2R was obtained (T Cell Diagnostics, Cambridge, Mass) and used according to the manufacturer’s instructions. The kit included two noncompeting monoclonal antibodies to IL-2R. Minimum sensitivity for the assay was 85 U/ml.
Chemiluminescent sandwich ELISA for IL-4 was based on the multiple antibody sandwich principle. Two specific antihuman IL-4 antibodies were purchased (Genzyme, Boston). The system included a monoclonal antibody as the first antibody, rabbit polyclonal anti-IL-4 antibody as the second antibody, and alkaline phosphatase (ALP) conjugated goat antirabbit antibody (TAGO, Inc, Burlingame, Calif) as the third antibody. There was also a substrate solution containing AMPPD with Emerald Amplifier (Tropix, Inc, Bedford, Mass). Relative chemiluminescent intensity was measured with a microplate luminometer (ML1000, Dynatech Laboratories, Inc, Chantilly, Va).

Table 1 — Patient Characteristics

Asthmatics Controls
Atopic Nonatopic Total
No. 32 45 77 75
Sex, F/M 18/14 29/16 47/30 40/35
Age, yr 38.7 ± 2.9t (15-72) 51.9 ±2.6 (21-75) 46.4 ±2.1 (15-75) 46.3 ± 1.7 (20-68)
Serum total, IgE, I U/ml 1267.6 ±216.6| (136-5183) 219.6 ±58.7 (17-2123) 660.9 ± 113.5 (17-5183) 87.0 ± 17.1 (5-280)
FEV,, % of predicted 87.1 ±2.7 (65-120) 83.0 ± 1.8 (62-110) 84.7 ± 1.5 (62-120) ND
PC20 Histamine, MG/ML 1.3 ±0.2 (0.12-4) 0.9 ±0.2 (0.12-4) 1.1 ±0.1 (0.12-4)
Specific IgE against Dp positive 32/32 0/45 32/77 0/75
Skin prick test positive 32/32 0/45 32/77 ND
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