Intranasal Allergen Research Articles

Nasal mucosal blood flow after intranasal allergen challenge

The nasal mucosal blood flow in patients with allergic rhinitis was determined at nasal allergen challenges with the 133Xenon washout method. Determinations were made in 12 subjects before and 15 minutes after challenge with diluent and increasing doses of allergen. The time course was followed in eight subjects by means of repeated measurements during 1 hour after a single allergen dose. Finally, the blood flow was measured after unilateral allergen challenge in the contralateral nasal cavity. A dose-dependent decrease in blood flow was found after nasal challenge with increasing doses of allergens, whereas challenge with diluent alone did not induce any changes. The highest allergen dose, which also induced pronounced nasal symptoms, resulted in a decrease in blood flow of 25% ( p < 0.001). The time-course study demonstrated a maximum decrease in blood flow 10 to 20 minutes after challenge and then a gradual return to baseline. Unilateral allergen challenge resulted in a decrease in blood flow in the contralateral, unchallenged nasal cavity, suggesting that part of the allergen-induced changes in blood flow were reflex mediated.

Untersuchungen zur Reproduzierbarkeit des intranasalen Provokationstestes1

Perennial allergic diseases of the upper respiratory tract are becoming more and more frequent. Treatment is difficult and indicated only if there is clear evidence that the suspected allergen definitely causes the symptoms. To date the intranasal allergen provocation test (INT) is the only possibility to prove the actuality of an allergen at the shock organ (e.g. the nasal mucosa). However, the validity of the INT is diminished because the test is handled differently by various authors. In this study we therefore examined the extraseasonal reproducibility of INT in 21 patients allergic to graminaceae. After determination of an individual allergen concentration for every subject the INT was repeated five times under standardised conditions (allergen lyophilised and standardised in biological units, application of the allergen solution to the inferior concha, rhinomanometrical measurement of the nasal flow before and 15 min. after the provocation). Using a flow reduction of 30 per cent as borderline value we found a high reproducibility of the INT. The nasal reaction was not diminished after repeating the test within 24 hours. The essential and so far unsolved problem of the INT is not due to the technical device but to the concentration of the allergen solution which must correspond to the natural exposition of the patient.

Studies on the allergen-challenged human nasal mucosa.

Contrary to the results reported on experimental anaphylaxis in animals, we could not discover any effect of intranasal allergen challenge on ciliary function, epithelial structures or subepithelial number of mast cells in 28 hay fever patients.

Intranasal allergen challenge during corticosteroid treatment

The effect of a corticosteroid drug on type I reactions in the nose was studied in eighteen hay fever patients. They were treated with a daily dosage of 800 microng beclomethasone dipropionate intranasally for I week, in a double-blind, placebo-controlled cross-over trial. Allergen challenge on the last day of each treatment period showed that steroid treatment diminished sneezing and rhinorrhoea, but the effect was not statistically significant (P = 0-10). Immediate nasal blockage was unaffected. There is a marked discrepancy between the minor protection offered by beclomethasone dipropionate in type I allergy, as suggested in this study and the marked efficacy of the drug in the treatment of hay fever. It is suggested that two factors may account for this discrepancy. First, the significance of "delayed" reactions for hay fever symptoms. Second, the difference between a single allergen provocation and continuous exposure. It is suggested that a slight steroid inhibition of immediate reactions following allergen provocation is potentiated during natural exposure due to inhibition of the priming of the end-organ.