Immunotherapy with keyhole lampet hemocyanin-conjugated decapeptide vaccine in cypress pollen allergy.

BACKGROUND: Cupressaceae pollen allergy is a world-wide pollinosis but immunotherapy has rarely been tested. Immunotherapy is usually allergen-specific but new forms may be targeted towards IgE. OBJECTIVES: A randomized, double-blind, placebo-controlled trial was carried out to assess the efficacy of a vaccine made of keyhole lampet hemocyanin (KLH)-conjugated decapeptide from the Fc(epsilon4) domain of the IgE in cypress pollinosis. METHODS: Sixty patients with cypress pollen allergy were studied. They were included on a suggestive clinical history, positive skin tests and nasal challenge to cypress pollen extract. Three intramuscular injections of the vaccine (250 microg) or placebo were administered monthly with a booster injection 5 to 8 weeks later. The primary end-point criterion was the threshold dose inducing a positive nasal challenge. The secondary end-point was the symptom-medication scores measured when cypress pollen grains were over 50 grains/m3. RESULTS: Nasal challenge before treatment was non-significantly different between the placebo and vaccine groups. After treatment there was no significant difference between the two groups. Pollen counts were over 50 grains/m3 for 8 weeks during the trial. There was no significant difference in total symptom scores between the placebo and vaccine groups. The vaccine was safe. CONCLUSIONS: The KLH-conjugated decapeptide vaccine was not effective in cypress pollen allergy.

Basophil activation during pollen season in patients monosensitized to grass pollens.

BACKGROUND: Basotest is a new basophil-activation test based upon the expression of CD63 (gp53) in the presence of allergens. It is an effective diagnostic test for pollen-allergic patients. However, it is not known whether Basotest results differ during the pollen season. METHODS: We examined the activation of basophils by Basotest in 13 patients sensitized only to grass pollen, before and during the pollen season, in order to assess whether Basotest could be used as a diagnostic test during the pollen season. Dose-response curves with 10-fold increasing concentrations of timothy grass pollen (10-4 to 100 AU) were carried out. RESULTS: Basophils were not activated spontaneously during the pollen season since the CD63 expression was below detectable levels before in vitro cell activation. A decreased percentage of activated basophils at the peak of activation was found in comparing the pre- and in-season tests, but all patients had a positive test. When basophil activation was at its peak, the allergen concentration was similar during the two periods. Moreover, the median area under the curve was significantly (P < 0.02) reduced during the season as compared to before the season. CONCLUSION: Basotest can therefore be used as a diagnostic test during the pollen season, but the allergen exposure needs to be characterized if quantitative studies are performed.

Superoxide dismutase biosensors working in non-aqueous solvent.

Enzymatic electrodes based on superoxide dismutase enzyme were developed. Using the superoxide dismutase enzyme sensor assembled according to the classical model, poor results were obtained. Results were improved by adopting a new way of assembling the biosensor using a cellulose triacetate layer in which the SOD enzyme is entrapped and sandwiched between two gas-permeable membranes, or using a kappa-carrageenan gel layer entrapping the enzyme, sandwiched between an external gas permeable membrane and an internal cellulose acetate membrane, coupled in each case to the oxygen amperometric transducer. Results obtained by applying the newly developed biosensor to assaying hydrophobic compounds showing radical scavenging properties, operating in dimethylsulfoxide, were also satisfactory.

Evaluation of radical scavenging properties of several plants, fresh or from a herbalist's, using a superoxide dismutase biosensor.

The experimental evaluation of properties of defence against free radicals represents an extremely interesting heuristic and applicational objective. Research was carried out to experimentally evaluate the scavenging properties of several fruits and plants, fresh or from a herbalist's using an amperometric superoxide dismutase (SOD) biosensor recently developed by the present authors. The superoxide radical was produced in solution using the xanthine/xanthine oxidase system; measurements were carried out by comparing biosensor response to superoxide radical both in the presence and absence of the sample considered.

New biosensor for superoxide radical used to evidence molecules of biomedical and pharmaceutical interest having radical scavenging properties.

A superoxide dismutase biosensor was used to determine the antioxidant properties of scavenger molecules and the antiradical activity of healthy and diseased human kidney tissues; this biosensor is based on the use of the enzyme superoxide dismutase (SOD), which is physically entrapped in a kappa-carrageenan gel membrane, and of a transducer consisting of an amperometric hydrogen peroxide electrode. Several compounds with scavenging properties were tested, including some commercial drugs.

A comparison of topical mequitazine and disodium cromoglycate in allergic conjunctivitis induced by a specific conjunctival provocation test.

PURPOSE: Twenty-two people with a history of grass pollen allergic conjunctivitis were enrolled outside the pollen season in this study to compare the efficacy of 0.05% mequitazine eyedrops with topical 2% disodium cromoglycate. METHODS: This randomized, double-blind study compared right and left eyes. Subjects received 2% disodium cromoglycate eyedrops in one eye and mequitazine vehicle in the fellow eye 4 times daily for 4 days. For the last instillation, mequitazine vehicle was replaced by one drop of 0.05% mequitazine and 15 min later a conjunctival provocation test (CPT) with grass pollen was performed. RESULTS: The sum of the scores for hyperemia and itching, and total composite score were lower after 0.05% mequitazine than after 2% disodium cromoglycate (p < 0.0001 in each case). The allergen threshold dose which elicited a positive allergic response was higher in the mequitazine group (p < 0.001). Both treatments showed good tolerance upon instillation. No adverse events related to study treatment occurred. CONCLUSIONS: These results demonstrate the superior efficacy of a single drop of 0.05% mequitazine 15 min before CPT compared with 2% disodium cromoglycate 4 times daily for 4 days.

In vitro diagnosis of cypress pollen allergy by using cytofluorimetric analysis of basophils (Basotest).

BACKGROUND: Cupressaceae pollen allergy is a worldwide pollinosis, but its in vitro diagnosis is notoriously difficult. The Basotest is a newly available in vitro test for the detection of allergen-specific IgE based on the level of cellular activation of basophils by using flow cytometry. OBJECTIVES: The Basotest was compared with the measurement of cypress pollen-specific IgE in highly selected patients. METHODS: We analyzed 34 patients allergic to cypress pollen selected on the basis of a suggestive clinical history and positive skin test and nasal challenge responses to cypress pollen extract. We also analyzed 8 patients with positive skin test responses to cypress pollen extract who did not present symptoms during the pollen season (intermediate group) and 33 control subjects. Sensitivity, specificity, and efficiency of the Basotest and serum-specific IgE levels measured by using the CAP System were determined in patients allergic to cypress pollen. Histamine release was studied in a selected group of patients. RESULTS: The Basotest was more sensitive (91.2%) than the CAP System (76%) for the in vitro diagnosis of cypress pollen allergy. A dose-response curve was observed in basophils obtained from patients allergic to cypress pollen. There were no false-positive results with either test (specificity 100%). The results of the Basotest or those of the CAP System did not correlate with the patients' in vivo threshold sensitivity assessed by skin tests and nasal challenge. CONCLUSIONS: The Basotest was found to be an effective diagnostic test in patients allergic to cypress pollen.

Comparison between nasal provocation tests and skin tests in patients treated with loratadine and cetirizine.

BACKGROUND: The effect of H1-blockers may differ depending on the target organ. OBJECTIVE: A double-blind, placebo-controlled study was carried out to compare the effect of a 7-day treatment with loratadine (10 mg daily) or cetirizine (10 mg daily) on nasal challenge with grass pollen grains and skin tests with allergen or histamine. METHODS: Twenty-four patients were enrolled, but the analysis was carried out on 23. Nasal challenge was carried out by using 5-fold increasing numbers of pollen grains. Skin prick tests were done with serial concentrations of allergens and 1 concentration of histamine. Patients were tested in a cross-over design, with each treatment being administered for the previous 7 days and with a 2-week washout period. RESULTS: By comparison with placebo, loratadine and cetirizine increased significantly the threshold number of pollen grains required to induce a positive nasal challenge (P <.001). There was no difference between loratadine and cetirizine. Skin test responses to allergen were significantly reduced by loratadine and cetirizine by comparison with placebo. Skin test responses to histamine were significantly decreased by the 2 H1-blockers, but they were more profoundly decreased by cetirizine than by loratadine. CONCLUSIONS: Both H1-blockers reduced similarly allergen-induced skin test and nasal challenge responses. Cetirizine was more effective on histamine skin test responses.

[Value of the conjunctival provocation test in evaluating the activity of 2 concentrations of anti-allergy eyedrops, mequitazine]. / Intérêt du Test de Provocation Conjonctivale (TPC) dans l'évaluation de l'activité de deux concentrations d'un collyre anti-allergique, la méquitazine.

PURPOSE: To compare the activity of topical 0.05% and 0.01% mequitazine versus vehicle in the prevention of allergic conjunctivitis induced by a conjunctival provocation test with allergens. METHODS: Forty subjects with a history of grass pollen allergic conjunctivitis were enrolled in this comparative, randomized, double-masked study. Fifteen minutes before the conjunctival provocation test, subjects received one instillation alone of 0.05% mequitazine eyedrops in one eye and in the fellow eye either one drop of 0.01% dose or vehicle, at the same dosage. Then a specific conjunctival provocation test (CPT) was performed with the allergen threshold concentration previously defined. The therapeutic efficacy was assessed by the decrease in a symptomatic composite score representing the allergic reaction. RESULTS: Topical mequitazine at the dose of 0.05% significantly decreases the intensity of the allergic reaction compared to vehicle. Moreover, the group treated with this dose needed a higher allergen concentration to trigger ocular signs. The 0.01% dose appears efficient only on itching, compared to vehicle. CONCLUSION: The results of this study support the efficacy and the onset of action of 0.05% mequitazine eyedrops versus 0.01% or vehicle in the prevention of allergic conjunctivitis induced by a conjunctival provocation test.

Effect of bronchial allergen challenge on in vitro cytokine release by peripheral blood mononuclear cells of atopic patients.

BACKGROUND: During the pollen season, peripheral blood mononuclear cells (PBMC) from allergic patients produce increased levels of Th2 cytokines after stimulation with allergen in vitro. We have studied the effect of a single bronchial provocation test (BPT) of allergic patients to determine whether allergen challenge in vivo modulates cytokine production by PBMC, after subsequent stimulation with the same allergen in vitro. METHODS: Twelve atopic asthmatic patients were challenged with the relevant allergen, and their PBMC, isolated before (T0) or 6 (T6) or 24 h (T24) after BPT, respectively, were cultured for 120 h in the presence or absence of the same allergen, after which cytokine production was measured by ELISA. RESULTS: Allergen-specific activation of the PBMC at T0 resulted in interleukin (IL)-5 and IL-13 production, but not in detectable levels of interferon-gamma and IL-4. BPT did not induce the secretion of the latter cytokines. However, IL-5 and IL-13 production was significantly decreased at T24, as compared to T0. No statistically significant differences were found between the production of IL-10 before and after BPT. CONCLUSIONS: In contrast to the effects of natural challenge with allergen, a decrease in the production of some Th2 cytokines by peripheral blood T cells was observed 24 h after BPT, suggesting a concomitant decrease in the frequency of allergen-specific T cells in the circulation.

Efficacy of mequitazine in comparison with placebo assessed by ocular challenge with allergen in allergic conjunctivitis.

Pharmacologic intervention in the management of allergic conjunctivitis was evaluated with different topical ocular agents in man. Their effect can be precisely assessed with the conjunctival provocation test (CPT). A potent specific H1-receptor antagonist, 0.05% mequitazine eye-drops, was tested in a double-blind randomized, placebo-controlled study using CPT with grass pollen allergens. Twenty healthy subjects allergic to grass pollen were included outside the pollen season after a positive CPT screening. They received one drop of 0.05% mequitazine in one eye and the vehicle in the contralateral eye in a random order, four times daily for 5 days. CPT was performed 15 min after the last instillation, and the threshold dose inducing a positive reaction was determined. Results were given by Abelson's composite score including redness, chemosis, tearing, and itching. Topical 0.05% mequitazine significantly reduced the composite score compared to placebo. The allergen threshold concentration which induced the positive conjunctival reaction was higher in mequitazine pretreated eyes. No side-effect was reported. These data clearly suggest that mequitazine has potential to treat allergic conjunctivitis.