Enhanced basophil histamine release and neutrophil chemotactic activity predispose grain dust-induced airway obstruction

Fractionation of swine barn dust and assessment of its impact on the respiratory tract following repeated airway exposure

The effects of repeated exposure to a range of doses of swine barn dust (SBD) on airway hyperresponsiveness (AHR) and inflammation were evaluated using a mouse model system. A number of components, including endotoxin and a number of feed proteins, were identified in SBD, and mice were exposed 20 min/d for 14 d to a log dilution series of nebulized SBD suspensions. AHR to methacholine was measured using head-out whole-body plethysmography, and the methacholine concentration inducing a 20% decrease in pulmonary airflow (PC(20) MCh) was calculated. At the end of the 14-d exposure period, bronchoalveolar lavage (BAL) fluids were recovered, cytokines (interleukin [IL]-1beta, IL-6, keratinocyte-derived chemokine [KC], and tumor necrosis factor [TNF]) in BAL were measured by enzyme-linked immunosorbent assay (ELISA), and leukocytes in BAL were counted. The PC(20) MCh was significantly lower in the group of mice that were exposed to the highest concentration of SBD than in controls or the group exposed to the lowest level of dust. Likewise, the group that was exposed to the highest level of SBD had significantly higher levels of IL-1beta, KC, and TNF than controls and some other groups. There were substantially more lymphocytes and monocytes in the BAL from mice that were exposed to the higher levels of SBD for the 14-d period, but neutrophils were not a part of this response. The SBD exposures used in these experiments induced chronic inflammatory phenotype responses, as indicated by the predominance of lymphocytes and monocytes, but not neutrophils, in BAL and by inflammatory cytokines detected. The association between the PC(20)MCh and dose of SBD suggests that a threshold of susceptibility occurs after a relatively low, chronic exposure to SBD.

Small nonspecialized farming as a protective factor against immediate-type occupational respiratory allergy?

BACKGROUND

In Poland small, nonspecialized farms, growing different crops and raising usually a few animals of various species constitute the majority.

OBJECTIVE

The aim of the case-control study was to evaluate the risk factors of work-related respiratory symptoms and occupational asthma and/or rhinitis in Polish farmers and investigate whether the farming characteristics may have influence on the prevalence of atopy and allergic diseases.

METHODS

The study groups comprised 100 cases who were farmers reporting work-related asthmatic and/or rhinitis symptoms from randomly selected family doctors practices (80 of 353) and 102 healthy controls. All subjects were examined by means of a questionnaire, skin prick tests (SPT) to common and occupational allergens, total serum immunoglobulin (Ig)E level and the presence of specific IgE and allergen-specific inhalation challenge tests were performed. The provocation tests were monitored with the spirometry, histamine challenge test and evaluation of nasal symptoms score and nasal washings.

RESULTS

Respiratory allergic disease was recognized in 68 symptomatic patients, including 41 cases because of occupational allergens (asthma n=38, rhinitis n=41). Step-wise logistic regression analysis confirmed the protective role of small farms against the development of work-related symptoms (OR 0.23; 95% CI 0.11, 0.47) as well as the significance of positive SPT to cereals (OR 5.55; 95% CI 1.6, 19.21) and storage mites (OR 3.73; 95% CI 1.27, 10.96) as a risk factor of these symptoms. Cereal farming (OR 13.75; 95% CI 2.39, 78.83) and positive SPT to cereals (OR 26.92; 95% CI 5.33, 135.9) and storage mites (OR 44.07; 95% CI 8.40, 231.1) were found to be significant risk factors of occupational asthma and/or rhinitis.

CONCLUSIONS

Cereal farming and hypersensitivity to cereals plays the significant role in the development of occupational asthma among Polish farmers. It also seems that working on small farms may protect farmers against work-related respiratory symptoms that are mostly because of allergy.

Allergen-specific conventional immunotherapy decreases immunoglobulin E-mediated basophil histamine releasability

BACKGROUND

Allergen-specific immunotherapy has proven to be clinically effective in the treatment of patients with atopic asthma; however, the mechanisms are still unclear. Several noted immunological changes include an increase of the allergen-specific IgG antibody, a reduction in the allergen-specific IgE antibody subsequent to transient increase, an allergen-specific T cell shift in cytokine production from Th2 to Th1, and a decrease in quantity and activity of basophils and mast cells.

OBJECTIVE

To analyse the changes of basophil histamine release in response to IgE-mediated and non-IgE-mediated stimuli before and after conventional house-dust mite immunotherapy in children who suffer from atopic asthma.

METHODS

Fourteen Dermatophagoides farinae (Df) sensitive asthmatic children with conventional immunotherapy were examined. Basophil histamine releasability was measured 0 months (just before immunotherapy), 4 months and 9 months after immunotherapy. Basophils were stimulated with Df and goat anti-human IgE antibody as IgE-mediated stimuli; and formyl-Met-Leu-Phe (fMLP) and calcium ionophore A23187 as non-IgE-mediated stimuli. Accordingly, the asthma symptom score was used to assess clinical outcome and the skin test reactivity to Df was measured.

RESULTS

In contrast to pre-immunotherapy activity, 4 and 9 months after immunotherapy there were significant decreases in histamine release by Df and by anti-IgE antibody. The histamine release by fMLP and by calcium ionophore showed no significant changes after immunotherapy. Histamine release by Df demonstrated significant correlation to that by anti-IgE antibody and by fMLP, yet there was no observable correlation between histamine release by Df and by calcium ionophore. The asthma symptom score decreased significantly 4 and 9 months after immunotherapy and showed significant correlation with histamine release by Df. The skin test reactivity (allergen/histamine ratio) remained constant 4 months after immunotherapy, but decreased significantly 9 months after immunotherapy.

CONCLUSION

Basophils have the potential to play an important role in the early clinical improvement of conventional immunotherapy in children with atopic asthma, which may be a result of the decreased IgE-mediated histamine releasability during immunotherapy.

Occupational asthma and rhinitis caused by multiple herbal agents in a pharmacist

BACKGROUND

Herb agents have been widely used for centuries in the Orient and they have been cultivated throughout Asia. There have been a few cases of occupational allergy caused by herb materials. We report a case of occupational asthma and rhinitis caused by six herb materials in a pharmacist working at a pharmacy.

OBJECTIVE

We sought the role of immediate hypersensitivity in herbal agent-induced asthma in a pharmacist.

METHODS AND RESULTS

The patient had strong positive responses on skin prick test to extracts of six herb materials: Chunkung (Cnidii rhizoma), Banha (Pinellia ternata), Sanyak (Dioscorea radix), Kangwhal (Ostericum koreanum), Danggui (Angelica radix), and Kunkang (Zingiberis rhizoma). Bronchoprovocation tests showed an early asthmatic response to Danggui extract. Serum specific IgE antibodies to Chunkung, Banha, and Sanyak were detected by ELISA with no specific IgE bindings to Kangwhal, Danggui, and Kunkang extracts. Twelve percent sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and IgE immunoblotting revealed one IgE binding component (60 kD) within Chunkung extract, two (10, 25 kD) in Banha, and four (33, 34, 65, 98 kD) in Sanyak. Basophil histamine release test revealed that Danggui extract could release a greater amount of histamine from basophils in the patient than in a healthy control.

CONCLUSIONS

Chunkung, Banha, and Sanyak may induce IgE-mediated bronchoconstriction in an exposed worker, and Danggui can cause bronchoconstriction by direct histamine-releasing effect from mast cells in a sensitized patient.