A growing body of evidence has implicated allergens derived from cockroaches as an important environmental factor that may aggravate asthma in sensitized persons. We present the case of a 30-year-old man with asthma and a cockroach allergy. Allergy skin testing confirmed hypersensitivity to cockroach extract, and a home visit revealed visual evidence of infestation and the presence of Bla g 1 German cockroach allergen in vacuumed dust. As is typical of patients with a cockroach allergy and asthma, multiple factors in addition to cockroach allergen appeared to aggravate the patient's asthma. A multimodality therapeutic regimen, which included medications as well as cleaning of the home, integrated pest management, and professional application of chemical controls, resulted in substantial clinical improvement. The pathophysiology, epidemiology, and clinical features of cockroach-allergic asthma are reviewed, and an approach to diagnosis and management is suggested. (+info)
(2/1144) Orally exhaled nitric oxide levels are related to the degree of blood eosinophilia in atopic children with mild-intermittent asthma.
Increased levels of nitric oxide have been found in expired air of patients with asthma, and these are thought to be related to the airway inflammatory events that characterize this disorder. Since, in adults, bronchial inflammatory changes are present even in mild disease, the present study was designed to evaluate whether a significant proportion of children with mild-intermittent asthma could have increased exhaled air NO concentrations. Twenty-two atopic children (aged 11.1+/-0.8 yrs) with mild-intermittent asthma, treated only with inhaled beta2-adrenoreceptor agonists on demand and 22 age-matched controls were studied. NO concentrations in orally exhaled air, measured by chemiluminescence, were significantly higher in asthmatics, as compared to controls (19.4+/-3.3 parts per billion (ppb) and 4.0+/-0.5 ppb, respectively; p<0.01). Interestingly, 14 out of 22 asthmatic children had NO levels >8.8 ppb (i.e. >2 standard deviations of the mean in controls). In asthmatic patients, but not in control subjects, statistically significant correlations were found between exhaled NO levels and absolute number or percentage of blood eosinophils (r=0.63 and 0.56, respectively; p<0.01, each comparison). In contrast, exhaled NO levels were not correlated with forced expiratory volume in one second (FEV1) or forced expiratory flows at 25-75% of vital capacity (FEF25-75%) or forced vital capacity (FVC), either in control subjects, or in asthmatic patients (p>0.1, each correlation). These results suggest that a significant proportion of children with mild-intermittent asthma may have airway inflammation, as shown by the presence of elevated levels of nitric oxide in the exhaled air. The clinical relevance of this observation remains to be established. (+info)
(3/1144) Persistent cough: is it asthma?
The aim of this study was to determine if children in the community with persistent cough can be considered to have asthma. A validated questionnaire was given to the parents of 1245 randomly selected children aged 6-12 years. Atopy was measured with skin prick tests. Children with persistent cough had less morbidity and less atopy compared with children with wheeze. Although the syndrome commonly referred to as "cough variant asthma" could not be shown in this study, a significant number of children with persistent cough had been diagnosed as having asthma and were treated with asthma medications including inhaled corticosteroids. Studies are urgently needed to determine the appropriate treatment for children with persistent cough. (+info)
(4/1144) Update on the "Dutch hypothesis" for chronic respiratory disease.
BACKGROUND: Many patients with chronic obstructive lung disease show increased airways responsiveness to histamine. We investigated the hypothesis that increased airways responsiveness predicts the development and remission of chronic respiratory symptoms. METHODS: We used data from 24-year follow-up (1965-90) of 2684 participants in a cohort study in Vlagtwedde and Vlaardingen, Netherlands. Increased airways responsiveness was defined as a PC10 value (concentration of histamine for which challenge led to a 10% fall in forced expiratory volume in 1 s) of less than 8 mg/ml. Information on respiratory symptoms was collected by means of a standard questionnaire every 3 years. Logistic regression was used to control for age, area of residence, cigarette smoking status, and sex. FINDINGS: Participants with increased airways responsiveness (1281 observations) were more likely than those without increased airways responsiveness (5801 observations) to develop the following symptoms during any 3-year follow-up interval: chronic cough (odds ratio 1.9 [95% CI 1.2-2.9]), chronic phlegm (2.0 [1.3-3.0]), dyspnoea (2.3[1.5-3.5]), asthmatic attacks (3.7[2.2-6.1]), and persistent wheeze (2.7[1.7-4.4]). The estimate of the odds ratio for the development of any of the six symptoms was 1.7 (1.2-2.3). Participants with increased airways responsiveness were less likely than those without this characteristic to show remission of these respiratory symptoms. The estimate of the odds ratio for the remission of any of the six symptoms was 0.42 (0.28-0.61). INTERPRETATION: These prospective analyses show that increased airways responsiveness is positively associated with the development of chronic respiratory symptoms and negatively associated with the remission of these symptoms in adults. (+info)
(5/1144) Early childhood infection and atopic disorder.
BACKGROUND: Atopy is of complex origins but the recent rise in atopic diseases in westernized communities points to the action of important environmental effects. One candidate mechanism is the changing pattern of microbial exposure in childhood. This epidemiological study investigated the relationship between childhood infections and subsequent atopic disease, taking into account a range of social and medical variables. METHODS: A total of 1934 subjects representing a retrospective 1975-84 birth group at a family doctor practice in Oxfordshire were studied. Public health and practice records were reviewed; temporal records were made of all diagnoses of infections and their treatments, all immunisations, and diagnoses of asthma, hay fever and eczema; maternal atopy and a number of other variables were documented. RESULTS: Logistic regression analysis identified three statistically significant predictors of subsequent atopic disease: maternal atopy (1.97, 95% CI 1.46 to 2.66, p < 0.0001), immunisation with whole-cell pertussis vaccine (1.76, 95% CI 1.39 to 2.23, p < 0.0001), and treatment with oral antibiotics in the first two years of life (2.07, 95% CI 1.64 to 2.60, p < 0.0001). There was no significant association found for maternal smoking, bottle feeding, sibship size, or social class. CONCLUSIONS: The prediction of atopic disease by maternal atopy mainly reflects the effect of acknowledged genetic factors. Interpretation of the prediction of atopic disorders by immunisation with wholecell pertussis vaccine and treatment with oral antibiotics needs to be very cautious because of the possibilities of confounding effects and reverse causation. However, plausible immune mechanisms are identifiable for the promotion of atopic disorders by both factors and further investigation of these association is warranted. (+info)
(6/1144) Detection of allergen-induced basophil activation by expression of CD63 antigen using a tricolour flow cytometric method.
In the field of allergy diagnosis, most in vitro functional tests are focused on basophils. Nevertheless, the very small number of circulating basophils limits these experiments and their clinical benefit remains controversial. As flow cytometry is a valuable tool for identifying cell populations, even at low concentrations, we developed a tricolour flow cytometric method for the study of allergen-induced basophil activation. Identification of cells was based both on CD45 expression and on the presence of IgE on the cell surface, since basophils express high-affinity receptors for IgE (Fc epsilon RI). Cell activation upon allergen challenge was assessed by the expression of CD63 antigen on the plasma membrane. Basophil isolation and activation (with the chemotactic peptide formyl-methionyl-leucyl-phenylalanine) were validated in 32 non-allergic patients. In 12 allergic patients, basophil stimulation by a relevant allergen was in most cases positive (10/12). Furthermore a concentration-dependent hook effect was observed. Of the allergic and non-allergic patients, none showed non-specific activation with an irrelevant allergen (specificity 100%). Overall, our preliminary results, even in a small population, suggest that this is a reliable and valuable method for the diagnosis of allergies complementing specific allergen IgE and skin test results. Obviously, additional clinical studies are needed to validate these first results. (+info)
(7/1144) Regulation of TH1- and TH2-type cytokine expression and action in atopic asthmatic sensitized airway smooth muscle.
CD4(+) T helper (TH)1- and TH2-type cytokines reportedly play an important role in the pathobiology of asthma. Recent evidence suggests that proasthmatic changes in airway smooth muscle (ASM) responsiveness may be induced by the autocrine release of certain proinflammatory cytokines by the ASM itself. We examined whether TH1- and TH2-type cytokines are expressed by atopic asthmatic sensitized ASM and serve to autologously regulate the proasthmatic phenotype in the sensitized ASM. Expression of these cytokines and their receptors was examined in isolated rabbit and human ASM tissues and cultured cells passively sensitized with sera from atopic asthmatic patients or control subjects. Relative to controls, atopic sensitized ASM cells exhibited an early increased mRNA expression of the TH2-type cytokines, interleukin-5 (IL-5) and granulocyte-macrophage colony-stimulating factor (GM-CSF), and their receptors. This was later followed by enhanced mRNA expression of the TH1-type cytokines, IL-2, IL-12, and interferon-gamma (IFN-gamma), as well as their respective receptors. In experiments on isolated ASM tissue segments (a) exogenous administration of IL-2 and IFN-gamma to atopic asthmatic serum-sensitized ASM ablated both their enhanced constrictor responsiveness to acetylcholine (ACh) and their attenuated relaxation responsiveness to beta-adrenoceptor stimulation with isoproterenol, and (b) administration of IL-5 and GM-CSF to naive ASM induced significant increases in their contractility to ACh and impaired their relaxant responsiveness to isoproterenol. Collectively, these observations provide new evidence demonstrating that human ASM endogenously expresses both TH1- and TH2-type cytokines and their receptors, that these molecules are sequentially upregulated in the atopic asthmatic sensitized state, and that they act to downregulate and upregulate proasthmatic perturbations in ASM responsiveness, respectively. (+info)
(8/1144) Observations on the use of tetracycline and niacinamide as antipruritic agents in atopic dogs.
Tetracycline and niacinamide were administered in combination to 19 atopic dogs to determine their effectiveness in controlling pruritus. The pruritus was controlled successfully in only one dog. One dog experienced diarrhea that was severe enough to warrant stopping the medication. (+info)