Skin test results but not serology reflect immediate type respiratory sensitivity: a study performed with recombinant allergen molecules.

The diagnosis of type I allergy, an IgE-antibody-mediated hypersensitivity disease affecting more than 25% of the population, is based on the measurement of allergen-specific serum IgE levels and provocation testing. Whether the determination of allergen- specific serum IgE levels can replace in vivo provocation testing for allergy diagnosis is a controversial issue. We used purified recombinant timothy grass and birch pollen allergens to compare by skin prick and nasal provocation testing as well as by serology in vivo sensitivity with antibody-binding capacity in 24 pollen allergic patients and eight control individuals. Results from biologic tests were correlated with each other and with allergen-specific IgE and IgG1-4 levels. IgE-reactive allergens induced immediate skin and nasal reactions, but the intensity of the allergic tissue reactions was not correlated with either the levels of allergen-specific IgE or the levels of allergen-specific IgG antibodies. Less frequently detected allergens with low IgE-binding capacity were able to induce strong allergic reactions comparable to those caused by major allergens with high IgE-binding capacity. In contrast, skin test and nasal provocation results were significantly correlated (r = 0.63, p < 0.01). Our study thus demonstrates on a molecular level that skin testing provides a better reflection of immediate type respiratory sensitivity than serologic measurements. These results have implications for allergy diagnosis and, in particular, for the selection of relevant allergen components for specific immunotherapy.

A direct comparison of the efficacy of antihistamines in SAR and PAR: randomised, placebo-controlled studies with levocetirizine and loratadine using an environmental exposure unit - the Vienna Challenge Chamber (VCC).

OBJECTIVE: The Vienna Challenge Chamber (VCC) is an established method for the controlled exposure of patients to specific allergens, used to make valid comparisons between antihistamines. The aim of the significantly more than loratadine at all time two placebo-controlled, randomised studies reported here was to compare the efficacy and safety of levocetirizine 5 mg od and loratadine 10 mg od in subjects suffering from seasonal allergic rhinitis (SAR) or perennial allergic rhinitis (PAR). SUBJECTS AND METHODS: During each study period, SAR and PAR subjects were exposed to grass pollen or house-dust mite allergens, respectively for 6 h on 2 consecutive days in the VCC. Each day, medications were administered 2 h after the start of the challenge; with a washout of at least 5 days between each period. The main criterion for evaluation of efficacy was the major symptom complex (MSC) for SAR and the complex symptom score (CSS) for PAR. RESULTS: The pattern of patients' response was similar in SAR and PAR. Both levocetirizine and loratadine were superior to placebo in alleviating SAR and PAR symptoms at all time intervals evaluated during the two study days. Levocetirizine decreased the mean MSC score intervals in SAR subjects, with the most marked difference observed on day 2 (p = 0.002). In PAR patients, although with borderline significance (p = 0.08), levocetirizine decreased the mean CSS more than loratadine. Levocetirizine appeared to have a faster onset of action than loratadine in SAR (45 min versus 1 h 15 min) and PAR (1 h versus 1 h 30 min). However, these apparent differences were not tested for statistical significance. Both medications were well tolerated and no treatment-related adverse events were reported. This level of antihistamine efficacy was maintained regardless of whether the subjects' rhinitis was seasonal or perennial. CONCLUSION: This study demonstrated that levocetirizine is superior to loratadine in improving symptoms in SAR and that there is a similar trend in PAR.

Immunotherapy with sublingual birch pollen extract. A short-term double-blind placebo study.

The aim of this double-blind placebo-controlled study was to evaluate the efficacy and tolerability of short-term birch pollen sublingual immunotherapy. Forty-one patients suffering from allergic rhinoconjunctivitis caused by Betula alba were included. Exclusion criteria were the following: undergoing immunotherapy within the last 2 years, contraindications to immunotherapy, pregnancy and nursing. The treatment schedule comprised a 28-day basic course, followed by a 3-month maintenance treatment. The evaluation of the parameters was performed before treatment and 4 months after the last maintenance dose. Skin prick test and conjunctival provocation test (CPT) in a dilution series were carried out to determine the threshold of the reaction. The objective parameters used were the diameter of the skin wheals and the lowest concentration, of the allergen extract to induce the symptoms of itching and reddening of the eyes. The allergic reaction in general was evaluated with the help of a 2-h birch pollen challenge in the Vienna Challenge Chamber (VCC); nasal flow and resistance was measured by rhinomanometry; and nasal secretion was quantified by weighing used handkerchiefs. Bronchial reactions were objectified by spirometry; subjective symptoms of the eyes, the nose and the bronchial tract were documented by the patients via a visual analog scale. Birch pollen specific IgE and IgG were evaluated by monoclonal antibody enzyme immunoassay before (T0) and after (T1) treatment. For statistics p < 0.05 was applied. At T0 there was no decisive difference in the in vitro and in vivo results between the two groups. After the treatment period (T1), actively treated patients showed a significantly higher tolerance to the birch pollen CPT (p < 0.01). The skin reaction was significantly lower than in the placebo group. Furthermore, actively treated patients produced less than half of the nasal secretion of placebo-treated patients during the challenge session. The rhinomanometry analysis during the challenge showed significant differences for verum and placebo in favor of the actively treated patients (p = 0.033). There was no significant difference in the specific IgE and IgG concentrations. The side effects and compliance during the treatment were comparable in both groups. In conclusion, sublingual immunotherapy is a well tolerated and clinically effective method of treatment.

Comparison of the effects of desloratadine 5-mg daily and placebo on nasal airflow and seasonal allergic rhinitis symptoms induced by grass pollen exposure.

BACKGROUND: Nasal congestion is a chronic symptom of seasonal allergic rhinitis (SAR) that is often difficult to treat with antihistamines. Desloratadine, a new, potent, H1-receptor antagonist has been shown to decrease nasal congestion in clinical trials and to maintain nasal airflow in response to grass pollen exposure. We compared the effects of desloratadine 5 mg and placebo on nasal airflow, nasal secretion weights and SAR symptoms, including nasal congestion, in patients exposed to grass pollen in an environmental exposure unit. METHODS: Forty-six grass pollen allergic SAR patients received desloratadine or placebo for 7 days, followed by a 10-day washout, and then crossed over to the other treatment for 7 days. A 6-h allergen exposure was performed at the end of each treatment period. RESULTS: Desloratadine was significantly superior to placebo in maintaining nasal airflow (P

Dose-dependent protection by azelastine eye drops against pollen-induced allergic conjunctivitis. A double-blind, placebo-controlled study.

The efficacy and tolerability of azelastine (CAS 58581-89-8) eye drops at three different doses (0.025%, 0.05% and 0.1%) were investigated in a double-blind, randomized, placebo-controlled, crossover study in 24 subjects with a history of allergic conjunctivitis/rhinoconjunctivitis, who were challenged, out of season, by airbone allergen in the "Vienna Challenge Chamber" (VCC). Subjects received a single dose of azelastine eye drops 60 min before the start of a 4 h challenge in the VCC. Additional local challenge, mimicking a gust of wind, was administered 15 min before the end of the session. Each of the 4 study days was separated by a 2 week washout period. Azelastine eye drops showed a dose-dependent inhibition of the development of itching of the eyes. The effect was most pronounced 15 min after the additional local challenge. A maximal effect was achieved at a dose of 0.05%. Similar effects were observed on lacrimation. Azelastine eye drops also dose-dependently inhibited the degree of conjunctival redness, measured by digital imaging, and tended to reduce the low incidence of chemosis observed. Ranking of the results of all symptoms for each treatment group confirmed the optimal effect at a dose of 0.05%. Azelastine eye drops had no effect on nasal and bronchial symptoms or on measurements of airways function (FEV1). No adverse effects of the treatments were reported. The data support the use of 0.05% azelastine eye drops in the treatment of allergic conjunctivitis/rhinoconjunctivitis.

Controlled comparison of the efficacy and safety of cetirizine 10 mg o.d. and fexofenadine 120 mg o.d. in reducing symptoms of seasonal allergic rhinitis.

BACKGROUND: The efficacy, onset and duration of action and safety of cetirizine 10 mg o.d., fexofenadine 120 mg o.d., and placebo were compared in this investigator-blinded, crossover study involving the use of the Vienna Challenge Chamber. METHODS: 40 volunteers with seasonal allergic rhinitis were exposed to a controlled grass pollen concentration for 6 h on 2 consecutive days. Subjective symptoms and objective measurements were recorded during the allergen exposure periods. RESULTS: Both active medications were significantly more effective than placebo and had a comparable onset of action in alleviating the symptoms of seasonal allergic rhinitis. The efficacy of both active drugs was comparable for the first 4 h after administration of the drugs on day 1 and day 2. However from 22 to 24 h after the first dose cetirizine was significantly superior to fexofenadine for the major symptom complex score and for sneezing. Concerning the total symptom complex score at day 2 fexofenadine could not reach superiority to placebo. No serious adverse events were reported. CONCLUSIONS: Cetirizine and fexofenadine were significantly better than placebo, also in reducing the symptom of nasal congestion. However cetirizine appears to have a longer duration of action than fexofenadine.

Environmental priming influences allergen-specific nasal reactivity.

BACKGROUND: Preceding mucosal response to one allergen leads to the priming of the nasal mucosal response to another allergen. This study aimed to determine whether environmental allergens, especially ubiquitous animal dander, can induce nasal priming. METHODS: We investigated 26 grass-pollen-allergic subjects with additional sensitization to other aeroallergens. We performed continuous allergen challenge for 2 h with 1500 Dactylis glomerata pollen/m3 in the Vienna challenge chamber. The nasal flow at 150 Pa was examined, and subjective scores were obtained every 15 min. Statistical analysis was calculated from the area under curve of nasal flow reduction by Student's t-test and the Mann-Whitney U-test. Alpha was 0.05. RESULTS: In subjects with positive cat-dander RAST (class of > or = 3), besides grass-pollen allergy, the specific nasal allergic reaction to Dactylis challenge was significantly pronounced (P < 0.01), and an earlier onset of reaction was evident. The same results were obtained with additional sensitization to dog dander (P < 0.05). Concomitant sensitization to mugwort also led to escalating symptoms (P < 0.05). CONCLUSIONS: These results indicate that a specific nasal allergic reaction is augmented by environmental priming caused by ubiquitous animal dander and possibly is influenced by the daily use of spices.