Role of allergy in nasal polyps of Thai patients.
(57/3663)
As distinct from many countries, allergy in Thailand is of the perennial type which may play a role in the formation of nasal polyps. Forty consecutive patients with nasal polyps and 30 normal subjects as control were studied at the Allergy Clinic, Department of Otolaryngology, Pramongkutklao Hospital. A positive clinical history and skin allergy testing are diagnostic criteria for allergy. In the nasal polyps group, these were 28 males and 12 females, aged between 12-65 years, with an average age of 38.5 years. In the control group, there were 18 males and 12 females, aged between 15-53 yeas, with an average age of 34 years. All had received prick skin testing with 6 common aeroallergens. The prick skin test was considered positive when the wheal was > or = 3 mm with surrounding erythema. Twenty-four of 40 patients (60%) with nasal polyps had a positive prick skin test, while 6 in the 30 control cases (20%) had a positive prick skin test. This difference was statistically significant (P = 0.0019), Odd's ratio = 6.0 which means allergic persons were 6 times more prone to have polyps form than normal persons. (+info)
Long term outcome of soybean epidemic asthma after an allergen reduction intervention.
(58/3663)
BACKGROUND: Asthma outbreaks due to the inhalation of soybean dust released from handling of soybean in the city harbour occurred in Barcelona, Spain from 1981 to 1987. The installation of bag filters in the responsible silo was followed by a substantial reduction of airborne soybean dust released into the atmosphere and the disappearance of asthma outbreaks. A study was undertaken to assess the relevant outcomes in asthma patients affected by soybean epidemic asthma eight years after this environmental intervention. METHODS: A repeat case-control study was performed in 1995 on a population of subjects with epidemic and non-epidemic asthma previously assessed in 1989. The same protocol was used in both surveys to collect data from patients via a questionnaire and respiratory function, skin and laboratory tests were performed under blinded conditions with regard to epidemic and non-epidemic status. Environmental soybean allergen in pollution filters was measured by means of a RAST inhibition technique. RESULTS: During 1995 and 1996 the 24 hour mean airborne levels of soybean allergen on a sample of 39 unloading days (range 31-269 U/m(3)) were systematically below the lowest level ever detected during an epidemic day (1500 U/m(3)). Measurable levels of serum IgE antibodies against soybean were still present in 55% of patients with epidemic asthma compared with 6.0% of those with non-epidemic asthma (p<0.05). These proportions were almost identical to those observed in 1989. The proportion of patients with soybean asthma with symptoms in 1989 who reported the absence of symptoms in 1995 was similar to the control subjects, so most of the relative risks (RRs) of improvement were near to 1. The only statistically significant differences between the two groups were a smaller proportion of patients with epidemic asthma showing improvement in terms of being woken up by attacks of coughing (RR improvement 0.47; 95% CI 0.22 to 0.99) and the need for treatment at the emergency room (RR improvement 0.63; 95% CI 0.41 to 0.96). CONCLUSIONS: Eight years after a large reduction in the levels of airborne soybean allergen half of the former soybean epidemic asthma patients were still sensitised to soybean. These results indicate an initial improvement in soybean epidemic asthma in the two years following the intervention with no further improvement in subsequent years. (+info)
Mite, cat, and cockroach exposure, allergen sensitisation, and asthma in children: a case-control study of three schools.
(59/3663)
BACKGROUND: The amount of allergen necessary to sensitise genetically "at risk" children is unclear. The relation between allergen exposure and asthma is also uncertain. METHODS: To ensure a wide range of allergen exposures the data from case-control studies of asthma in children aged 12-14 years attending three schools in Los Alamos, New Mexico and Central Virginia were combined. Skin prick tests to indoor and outdoor allergens and bronchial hyperreactivity to histamine were assessed in children with and without symptoms of asthma. The concentration of mite, cat, and cockroach allergens in dust from the children's homes was used as a marker of exposure. RESULTS: Three hundred and thirty two children (157 with asthmatic symptoms and 175 controls) were investigated. One hundred and eighty three were classified as atopic on the basis of allergen skin prick tests and 68 as asthmatic (symptoms plus bronchial responsiveness). The prevalence and degree of sensitisation to mite and cockroach, but not cat, was strongly associated in atopic children with increasing domestic concentrations of these allergens. Asthma was strongly associated with sensitisation to indoor allergens (p<10(-6)) and weakly to outdoor allergens (p = 0.026). There was an association between current asthma and the concentration of mite allergen amongst atopic children (p = 0.008) but not amongst those who were specifically mite sensitised (p = 0.16). CONCLUSIONS: The domestic reservoir concentration of mite and cockroach, but not cat, allergen was closely related to the prevalence of sensitisation in atopic children. However, the prevalence of current asthma had a limited relationship to these allergen measurements, suggesting that other factors play a major part in determining which allergic individuals develop asthma. (+info)
IL-3 does not affect the allergic airway responses and leukotriene production after allergen challenge in rats.
(60/3663)
T cell cytokines are important in asthma. Interleukin (IL)-3, an important growth factor for mast cells and eosinophils has been shown to be increased in the airways of asthmatic subjects, but its precise functions are uncertain. The aim of this study was to determine whether recombinant human (rh) IL-3 affected airway responses, inflammation and leukotriene production after antigen challenge in Brown Norway (BN) rats. Having established that rhIL-3 (>12.5 microg subcutaneously b.i.d. for 4 days) caused a doubling of mast cell numbers in the airways of BN rats, sensitized rats were pretreated with rhIL-3 (50 microg) or vehicle subcutaneously b.i.d. for 4 days. Ovalbumin (OA) challenge was performed and the early (EAR), and late (LAR) airway response and the associated biliary leukotriene (LT) excretion measured. The pulmonary cellularity was evaluated by means of lung digestion 8 h after challenge. IL-3 increased the number of eosinophils isolated from the lungs after antigen challenge (0.77+/-0.23 versus 0.38+/-0.12 x 10(6) cells, p=0.03). However, there were no effects on the numbers of neutrophils, lymphocytes and macrophages. Neither the EAR nor the LAR after OA challenge were altered by IL-3. Likewise biliary cysteinyl-LT excretion was similar in IL-3-treated animals and controls after challenge. In conclusion, interleukin-3 caused an increase in the numbers of mast cells and eosinophils around the airways without affecting the magnitude of either early or late airway responses or mediator release after antigen challenge. The present results suggest that airway inflammation can occur in rats without increasing the allergic asthmatic response. (+info)
Effect of respiratory syncytial virus on subsequent allergic sensitization to ovalbumin in guinea-pigs.
(61/3663)
Children with acute respiratory syncytial virus (RSV) bronchiolitis often develop recurrent wheezing, asthma and allergic sensitization, but the role of RSV in the pathogenesis of these sequelae is unclear. This study examined whether RSV infection potentiates subsequent allergic sensitization, airway hyperresponsiveness (AHR) and airway inflammation induced by repeated exposures to aerosolized ovalbumin (OA) in guinea-pigs. Guinea-pigs received either RSV or sham inoculum, followed by exposures to OA- or saline-containing aerosols to form the following groups: 1) noninfected, nonsensitized controls (sham/saline group); 2) RSV-infected, nonsensitized animals (RSV/ saline group); 3) noninfected, OA-sensitized animals (sham/OA group); 4) RSV infection and first OA exposure on the same day (RSV/OA group), and 5) RSV infection six days prior to first OA exposure (RSV6/OA group). Three days after the final aerosol exposure, circulating OA-specific immunoglobulin (Ig)G1 antibody titres and AHR to inhalation acetylcholine challenge were measured and morphometry performed to evaluate allergic inflammation of the airways. OA-exposed animals developed OA-specific IgG1 antibodies, AHR and airway eosinophilia (sham/OA, RSV/OA and RSV6/OA groups. RSV infection alone induced significant AHR and airway eosinophilia (RSV/saline group). RSV infection, and concomitant exposure to OA (RSV/OA group) enhanced OA-specific IgG1 antibodies, but not airway eosinophilia or AHR. Such increases were not observed in the RSV6/OA group. In conclusion, respiratory syncytial virus potentiates the production of ovalbumin-specific immunoglobulin G1 antibodies in guinea-pigs, but circulating titres of these antibodies do not reflect the extent of airway hyperresponsiveness or airway inflammation. In addition, respiratory syncytial virus infection alone can produce slight increases in airway hyperresponsiveness that are associated with increased numbers of eosinophils in the airways. (+info)
The prevalence of reported asthma is independent of exposure in house dust mite-sensitized children.
(62/3663)
In areas with low house dust mite (HDM) allergen exposure, both mite sensitization and asthma prevalence are low. In most other areas, HDM allergen exposure is higher than the threshold for sensitization. In this setting, is HDM allergen exposure a factor which is causally related to the development of asthma in HDM-sensitive individuals? To answer this question, the cumulative prevalence of asthma was evaluated in a group of 157 schoolchildren, aged 10 and 11 yrs, who were allergic to HDM allergen, and compared it with HDM allergen exposure and atopic status, using univariate and multivariate analysis. HDM allergen levels were measured in mattress dust using an enzyme-linked immunosorbent assay (ELISA) method. Of mattress dust samples, 94% had an HDM allergen level >2 microg x g dust(-1). Atopy was evaluated by means of skin prick tests using five common allergens. Among the predictive variables studied by means of univariate analysis, only the number of positive skin tests and male sex correlated with asthma prevalence, but not HDM allergen exposure. Logistic regression analysis also demonstrated that the number of positive skin tests correlated with asthma prevalence (odds ratio (OR)=1.38, p=0.05), whereas the OR for HDM allergen exposure was 1.0. This survey suggests that, in a geographical area with high HDM allergen exposure, asthma prevalence is not linked with HDM allergen levels. (+info)
Allergen exposure, atopy and smoking as determinants of allergy to rats in a cohort of laboratory employees.
(63/3663)
This study aimed to examine the relationship between exposure to rat urinary allergens, atopic status, smoking and the development of allergic symptoms and specific sensitization. It is a case-referent analysis of a cohort of 342 newly employed laboratory animal workers. Cases comprised persons developing symptoms of laboratory animal allergy or a positive skin prick test to rat urinary allergens; each was matched with up to two asymptomatic referents. Subjects were assigned to categories of exposure based on measurements of airborne rat urinary allergens. Of the cases, 80% reported that their symptoms started within 2 yrs of employment. The odds ratio (OR) for development of each symptom type (respiratory, eye or nose and skin) and of an immediate skin test reaction was increased in those with direct contact with rats. A gradient of increasing OR for the development of any such symptom across exposure categories was found; for respiratory symptoms and skin test reactions the OR for subjects in the highest exposure category were lower than those in intermediate categories, a pattern attenuated when the analysis was confined to outcomes developing within 2 yrs of first exposure. Atopy increased the OR of most outcomes as did cigarette smoking, although there was no evidence of a relationship between smoking and the development of a specific skin test reaction. In conclusion, allergen exposure was confirmed as the most important determinant of laboratory animal allergy; by implication, measures to reduce exposure may be the most effective means to reduce its incidence. (+info)
Successful treatment of alopecia areata-like hair loss with the contact sensitizer squaric acid dibutylester (SADBE) in C3H/HeJ mice.
(64/3663)
A type of hair loss closely resembling human alopecia areata has been described in C3H/HeJ mice. In order to test the assumed analogy with human alopecia areata, we investigated the efficacy of treatment with the contact allergen squaric acid dibutylester. In 12 C3H/HeJ mice with alopecia areata an allergic contact dermatitis was induced and elicited weekly on one side of the back by topical applications of squaric acid dibutylester. Overt hair regrowth was observed only on the treated side of the back in nine of 12 mice. Histopathologic examination revealed a change in the distribution of the inflammatory infiltrate from a dense perifollicular lymphocytic infiltrate around the mid and lower regions of hair follicles in untreated skin to a uniform presence in the upper dermis in treated skin. Immunohistomorphometric studies revealed that treatment with squaric acid dibutylester increased the CD4+/CD8+ ratio from approximately 1:2 in untreated alopecia areata to 1:1 in treated alopecia areata. Additional immunohistochemical investigations showed an aberrant expression of major histocompatibility complex class I, major histocompatibility complex class II and intercellular adhesion molecule 1 on keratinocytes of the mid and lower parts of hair follicles in untreated alopecia areata. In successfully treated skin ectopic major histocompatibility complex class I and II expression was clearly reduced, whereas intercellular adhesion molecule 1 expression showed only minor changes. In conclusion, alopecia areata-like hair loss in C3H/HeJ mice responded to treatment with the contact sensitizer squaric acid dibutylester analogous to human alopecia areata. Moreover, successful treatment changes the aberrant expression of major histocompatibility complex class I and II in a way similar to that observed in human alopecia areata. These observations support the concept that alopecia areata-like hair loss in C3H/HeJ mice can be utilized as an appropriate model for the study of human alopecia areata. (+info)