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Notes: Airway provocation tests such as the methacholine inhalation test or histamine inhalation test are commonly used for the quantitation of the airway hyperresponsiveness characteristic of asthma. The reduced provocation concentration of methacholine (PC20M) or histamine (PC20H) required to produce a 20% fall in FEV1 may be due to a number of underlying mechanisms, particularly airway mucosal inflammation. The characteristic eosinophilic mucosal inflammation of asthma apparently contributes to hyperresponsiveness through an enhancement of neuromuscular responses to methacholine and histamine in addition to increased responses to various stimuli through the release of inflammatory mediators. Methacholine airway hyperresponsiveness and airway mucosal inflammation usually are both present in asthma, but these findings do not always coexist. Patients with chronic cough and a normal PC20M may have eosinophilic airway inflammation; treatment with inhaled steroid can reduce the cough, sputum production and the number of eosinophils and mast cells in the sputum. Airway responses in provocation tests with histamine or methacholine seem to depend, at least in part, upon direct stimulation of airway smooth muscle and have been referred to as direct tests of airway responsiveness. In contrast, tests with stimuli such as allergen or adenosine, which elicit mediator release, have been referred to as indirect tests of airway hyperresponsiveness. There are complex interrelationships and an interdependence between methacholine airway hyperresponsiveness and airway inflammation; progress in the assessment of underlying mechanisms has been greatly enhanced by biochemical, immunologic and pathologic-type measurements in various types of specimens from the airways to directly assess the pathogenetic processes. Some features of asthma such as exercise and nocturnal symptoms correlate well with the level of methacholine airway hyperresponsiveness. Conversely, the occurrence of cough or the occurrence of asthmatic attacks are not predicted accurately by a measurement of methacholine airway hyperresponsiveness. The assessment of asthma severity seems to require the consideration of a number of types of parameters including the level of ongoing symptoms, need for inhaled B2-agonist, frequency and severity of acute attacks, level of treatment required to maintain control of asthma, baseline airflow rates and tests of variability of airflow such as serial measurements of variability of PEF or of PC20M. Measurement of the PC20M is a sensitive test of changes in airway responsiveness and can be useful in serial measurements. In some instances, airway reactions can be identified by serial measurements of PC20M but not by serial measurement of airway calibre such as the FEV1.

Notes: In recent studies, sputum smear cell counts were found to be reproducible and usefully applied to research in asthma and other airway conditions. However, cell definition on the smears is poor, and the procedure is tedious and has limited utility. The objective of this study is to improve the methods of sputum examination. The subjects used in this study were people with bronchitis or asthma from whom sputum could be obtained. By inverted microscopy, portions of fresh sputum were selected to exclude salivary contamination. These portions were exposed to different volumes of dithiothreitol for varied lime intervals. We used the resulting cell suspensions to perform total cell counts and prepare cytospins for differential cell counts and immunohistochemical stains for GM-CSF, EG2, TNFα and IL-8. Cytospins were compared with smears for differential cell counts on the same sputum specimens. Excellent cell dispersion and definition in cytospins could be observed. The time required for differential cell counting on cytospins was reduced and cytospin counts were more reproducible than smears. Greater duration of treatment of sputum with dithiothreitol tended to increase total cell counts and significantly decreased EG2 staining hut had no effect on differential cell counts or the cytokine cell components. Therefore the proposed method of sputum examination involving cell dispersion and use of cytospins overcomes a number of the disadvantages of the examination of smears.

Notes: Non-allergic bronchial hyper-reactivity is a feature of most patients with asthma. We have measured non-allergic bronchial reactivity to inhaled histamine and methacholine in thirteen asthmatic subjects before and after allergen inhalation in the laboratory. The allergen inhalation produced mild early asthmatic responses (19–40% FEV1 fall) in all thirteen, additional definite late asthmatic responses (17–29% FEV1 fall) in four, and equivocal late asthmatic responses (5–11% FEV1 fall) in five. Following allergen inhalation, non-allergic bronchial reactivity increased in seven for up to 7 days. The seven included all four with definite late asthmatic responses and three of the five with equivocal late asthmatic responses. We conclude that allergens make asthma worse, partly through non-allergic mechanisms, and that avoidance of allergens is important in reducing non-allergic bronchial hyper-reactivity.

Notes: Observations in two subjects undergoing three allergen challenges for a drug study suggested ‘priming’ of the late sequelae, namely allergen-induced increase in airway responsiveness. Both subjects had rhinitis and asthma limited to the ragweed season, near normal out-of-season histamine PC20, and extreme IgE sensitivity to ragweed. Both had an isolated early response with no change in histamine PC20 after the first allergen challenge. Significant (3.5- to 5.8-fold) reductions in histamine PC20 occurred after the second and third allergen challenge in Subject 1, and after the third challenge in Subject 2; this was associated with equivocal 5–8% late responses. Such a ‘priming’ effect, the prevalence of which is not known, may be important in the pathogenesis of naturally occurring allergic asthma, and in the design of clinical trials involving repeated allergen inhalations.

Notes: Oxatomide is an H1, receptor antagonist, which also inhibits antigen-induced mediator release from sensitized mast cells and basophils. The effects of ingested oxatomide (30 mg/capsule) were compared with those of chlorpheniramine (5 mg/capsule) in a double-blind non-crossover study in two groups of twenty-five subjects with ragweed pollen-induced hay fever during the pollen season. Oxatomide or chlorpheniramine was started when symptoms became troublesome and was used in a dose of two to four capsules daily according to severity. Other medications were added, in a standardized way, if hay fever symptoms were not controlled by the test capsules. Forty-one subjects completed the study; nineteen received oxatomide and twenty-two chlorpheniramine. Mean symptom scores, number of test capsules and number of doses of additional medication were not significantly different between the two groups. Drowsiness was reported by subjects in both groups but was worse in the chlorpheniramine group (P〈0.05). We conclude that, in the studied doses, oxatomide is as effective for the treatment of allergic rhinoconjunctivitis as chlorpheniramine and produces less drowsiness.

Notes: Local exudation at the sites of allergic and histamine-induced cutaneous reactions, was measured with an in vivo double-labelling procedure, based upon local serial simultaneous measurements of indium-113 m (113mIn) labelled transferrin and technitium-99m labelled red blood cells (99mTc RBC). Analyses depended upon the reaction index i.e. comparison of the ratio of 113mIn/99mTc counts at the reaction site with the ratio of 113mIn/99mTc at the corresponding unreacted site in the skin of the opposite arm.Reaction indices were initially significantly elevated at the sites of histamine and allergic reactions. After the first hour, there was a progressive reduction at histamine sites indicating a tapering of the local accumulation of indium-labelled transferrin. By contrast allergic reaction sites showed a continuing increase in the reaction index after one hour. During the first hour the curves were comparable, but they diverge and were significantly different after one hour (0.05 〉 P 〉 0.02). This is consistent with the known occurrence of late cutaneous responses at the site of allergic but not histamine reactions.

Notes: This study evaluated a research method to examine an exacerbation of asthma induced by corticosteroid withdrawal. Ten non-smoking adult asthmatics who were stable on treatment with inhaled steroid underwent a graded reduction of the daily dose by 200 μg at weekly intervals until an exacerbation of symptoms occurred. A daily symptom, peak expiratory flow rate (PEF) and medication diary was kept. Weekly clinic visits were used to assess symptoms, spirometry, methacholine airway responsiveness (expressed as the provocative concentration to cause a fall in FEV1 of 20%, PC20), circulating eosinophils, basophils and their progenitors (Eo/B-CFU), and sputum inflammatory cells. The laboratory tests were performed blind to the clinical details. Each subject developed an exacerbation of symptoms, on average at 16 (70–26) days after the onset of steroid reduction. This was accompanied by a deterioration in each of the objective measures. There was a fall in FEV1 by 320 ml (s.e.m. 9.5) and in PC20 from 0.8 to 0.43 mg/ml. Circulating eosinophils rose from 114 (24) × 103/ml to 227 (50) × 103/ml and Eo/B-CFU rose from 31 (5.6) to 44(11.3)/106 cells. Sputum developed in five subjects and contained 36 (5.2)% eosinophils and 1.98 (0.21)% metachromatic cells (mast cells or basophils). The symptom diary and weekly questionaire were demonstrated to be valid and responsive to change. A deterioration indicated by the daily symptom score preceded changes in PEF. Treatment by an increase in steroid was followed by reversal of each of the changes. We conclude that this research method can safely produce and examine a mild exacerbation of asthma, and that an increase in airway inflammation is an early feature.

Notes: Background There is little information on the repeatability of cell counts and fluid-phase measurements in nasal fluid obtained by different methods of nasal lavage.Objective To compare the repeatability and validity of total and differential cell counts and eosinophil cationic protein (ECP) in nasal secretions obtained by two methods of nasal lavage.Patients and methods Twelve healthy subjects and twelve subjects with clinically stable allergic rhinitis were randomly assigned to two nasal lavages (separated by 48 h), by one of two methods in the first week and by the second method in the following week. One method was a modification of the method described by Greiff et al. and Grunberg and coworkers and the other was that described by Naclerio and coworkers.Results Both methods of nasal lavage gave poorly repeatable eosinophil counts and ECP in normal subjects but better repeatability in subjects with rhinitis. The modified Greiff/Grunberg method gave higher and more repeatable total cell count and, in subjects with rhinitis, more reproducible ECP levels compared with the Naclerio method. Both methods were able to discriminate between healthy and rhinitic subjects: mean ± SD eosinophil percentage count and eosinophil cationic protein differences were 4.5 ± 4% (P 〈 0.05) and 24.5 ± 46.9 µg/L (P 〈 0.05), respectively, with the modified method and 7.0 ± 4% (P 〈 0.05) and 26.9 ± 68 µg/L (P 〈 0.05), respectively, with the Naclerio method.Conclusion Both methods are valid and discriminate between normal and rhinitic subjects. In subjects with rhinitis, although the repeatability of eosinophil counts is similar by both methods, the modified Greiff/Grunberg method gives more reproducible ECP measurements, compared with the Naclerio method.

Notes: An easy and safe dose-response histamine-inhalation test is described, to measure the level of non-specific bronchial reactivity.The test was performed in 307 subjects. Non-specific bronchial reactivity was increased in 3% of presumed normal subjects, in 100% of active asthmatics and in 69% of asymptomatic asthmatics with previous symptoms only at times of exposure to clinically relevant allergens. It was also increased in 47% of patients with cough and no other chest symptoms, in 40% of patients with rhinitis and vague chest symptoms not by themselves diagnostic of asthma, and in 22% of patients with rhinitis and no chest symptoms.The patients with asthma were studied when their asthma was well controlled and when their minimum drug requirements had been established. The mean level of bronchial reactivity increased with increasing minimum drug requirements. The level of bronchial reactivity also showed a strong negative correlation with the forced expiratory volume in 1 sec (FEV1). Atopic subjects, with or without asthma, showed a significant positive correlation between the level of bronchial reactivity and atopic status as indicated by the number of positive allergy skin tests.