Physico-chemical and clinico-immunologic studies on the allergenic significance of Aspergillus tamarii, a common airborne fungus.

Aspergillus-derived inhalant allergens play an important role in the etiology of allergic respiratory diseases. In the present study, we investigated the allergenic potential of Aspergillus tamarii, quantified its airborne content, identified its major/minor allergens, evaluated heterogeneity of patients' IgE response to its allergens and cross-reactivity of its allergens with other Aspergillus allergens. Skin prick tests with A tamarii extract were performed on 300 patients of bronchial asthma/allergic rhinitis and 20 healthy volunteers. Sixty-six patients (22%) elicited positive cutaneous reactions to A tamarii extract. Only one of the 20 non-allergic healthy volunteer showed a mild positive cutaneous reaction. Allergen-specific IgE levels increased with increase in patients' cutaneous response (0% in negative to 100% in 3+/4+). The skin positivity and allergen-specific IgE levels were significantly higher in patients compared to healthy volunteers (P>0.05). However, no differences were found for these two parameters among patients of bronchial asthma, allergic rhinitis and bronchial asthma with allergic rhinitis. The airborne A tamarii allergen content was highest in February and October. A tamarii extract revealed at least 22 proteins (13.3-120 kDa). Seventeen of these proteins bound patients' IgE with six being major allergens (13.3, 23, 25, 34, 39.5, 43 kDa). Three major allergens (13.3, 34, 43 kDa) were found to cross-react with A flavus and one (34 kDa) with A niger. Our results revealed that A tamarii allergen(s) are present in the air, which might serve as important inhalant allergens in IgE-mediated allergic respiratory diseases.

Quantification of airborne Aspergillus allergens: redefining the approach.

BACKGROUND: Airborne Aspergillus species are significant environmental components involved in the pathogenesis and persistence of allergic respiratory diseases. The detection and quantification of airborne allergens is important to elucidate the clinical implications of environmental exposure of patients suffering with allergic asthma and/or allergic rhinitis. OBJECTIVE: The authors report a simple volumetric approach to measure atmospheric concentration of four common airborne species of Aspergillus-A. flavus, A. fumigatus, A. niger, and A. tamarii. METHODS: As particulate aeroallergens may also exist in amorphous form in addition to morphologically identifiable fungal spores/hyphae, a volumetric technique using membrane filters was developed for simultaneous quantification of (a) viable Aspergillus counts, i.e., colony-forming units (cfu)/m(3), and (b) actual Aspergillus allergen content (ng/m(3)) in the air. Further, immunochemically quantified airborne Aspergillus allergens were compared with their corresponding colony counts. RESULTS: The average monthly aerial counts of the four Aspergillus species recorded during the sampling year were A. flavus: 0.25-15.2 cfu/m(3); A. fumigatus: 1.25-15.6 cfu/m(3); A. niger: 0.75-16.0 cfu/m(3); and A. tamarii: 0.5-11.8 cfu/m(3) of air. Aerial Aspergillus allergen(s) concentration varied from species to species: A. flavus: 26.8-680.8 ng; A. fumigatus: 18.0-380.4 ng; A. niger: 28.2-1879.0 ng; and A. tamarii: 9.2-238.3 ng/m(3) of air. Seasonal distribution of airborne colony counts of the four species didn't correlate with their respective allergen content. CONCLUSION: Aspergillus allergens were present in the air of Delhi area throughout the year with seasonal variations. The authors feel that by using the immunochemical technique it will be possible to measure actual exposure of patients to various airborne Aspergillus allergens.

Effect of azelastine nasal spray on histamine-and allergen-induced skin wheal response in patients with allergic rhinitis.

Effect of azelastine nasal spray on histamine-and allergen-induced skin test response in patients suffering with allergic rhinitis was evaluated. Baseline cutaneous response to histamine and 18 common allergen extracts were recorded by skin prick tests on 10 patients. The patients were then advised to take azelastine nasal spray (1 spray per nostril, twice daily; 0.28 mg/dose). This pediatric dose is reported to be effective also in adults (age > or = 12 years) with improved tolerability as compared with usually recommended adult dose of 2 sprays per nostril twice daily. Skin tests were repeated 2 and 6 hours after single dose, as well as after 6 days of continuous treatment. We did not find any significant difference in skin wheal response with single dose and 6 days' treatment of azelastine nasal spray (p > 0.05). It is concluded that diagnostic allergen skin tests may be performed on patients undergoing azelastine nasal spray treatment (0.28 mg/dose, twice a day) during their symptomatic period.