The effect of desloratadine on patch test reactions in Chinese patients.

BACKGROUND: Few data on the effect of antihistamines on patch test results in Chinese patients are currently available. OBJECTIVES: To evaluate the effect of desloratadine on patch test reactions. METHODS: Patients known to have at least one strongly positive (+ +) test with an allergen were re-patch tested after 14 to 70 days (average time interval 26.3 days) of administering oral desloratadine 5 mg twice a day for 5 days before and during the test. Patch testing was performed with the previously recognized allergen according to the guidelines of the ICDRG. The -to + + + system was converted into numeric values (0, 1, 2, 3, 4) for statistic evaluation. RESULTS: Of the 58 chambers (47 patients), which were all strongly positive (+ +) during the 1st patch test, the situation was unchanged in 51 chambers; 4 + reactions and 2 + + + reactions were observed; and 1 chamber was negative. There was no statistically significant difference when comparing the scores of the 1st assessment with those of the 2nd (p = 0.206). If the patch test reaction of the patient who dropped out of the trial had changed from strongly positive (+ +) to negative, there would still have been no statistically significant difference between the score of the 1st assessment with those of the 2nd ( p = 0.107). CONCLUSIONS: The reaction of a patch test is not hampered by doubling dose of desloratadine. The anti-inflammatory effects of desloratadine on patch test reaction may be limited.

CD203c-based basophil activation test in allergy diagnosis: characteristics and differences to CD63 upregulation.

BACKGROUND: The basophil activation test (BAT) based on CD203c upregulation has been validated as a reliable tool for the diagnosis of IgE-mediated allergies. Nevertheless, CD203c-based BAT is hardly comparable with that of CD63-based tests, as the mechanisms of CD203c versus CD63 induction differ considerably. The aim of the present study was to identify potent influencing factors of the CD203c-based BAT and to emphasize differences between CD63 and CD203c detection. METHODS: CD203c-based BAT was determined in 82 healthy controls and in 79 allergic patients. The effects of interleukin (IL)-3 and degranulation enhancing substances were investigated and compared with CD63 upregulation. Furthermore, the influence of different storage conditions and incubation times was evaluated and the impact of antiallergic drugs on the test results was assessed. RESULTS: CD203c and CD63 expression was rapidly upregulated reaching a maximum after 20-30 min. Basophil CD203c upregulation assayed after storage times up to 48 h declined already after 4 h. IL-3 treatment increased CD203c and CD63 baseline levels and decreased basophil CD203c responses in a dose-dependent manner. In contrast, cytochalasin B and latrunculin B did not affect CD203c responses but decreased CD63-based BAT. Finally, therapeutic concentrations of dimetindene and desloratadine did not affect CD203c upregulation. CONCLUSION: CD203c-based basophil activation test should be performed preferentially within 4 h after taking the blood samples. Priming and degranulation-enhancing factors are not required for CD203c-based BAT. In contrast to skin testing, CD203c-based BAT can be performed in patients undergoing antiallergic treatment. © 2010 International Clinical Cytometry Society.

Single-dose desloratadine and montelukast and allergen-induced late airway responses.

Montelukast and desloratadine synergistically inhibit the allergen-induced early asthmatic response. Montelukast also suppresses the allergen-induced late asthmatic response, but there are no reports on the effect of desloratadine or the combination on the allergen-induced late asthmatic response. Atopic asthmatics (n = 10) completed a multicentric randomised double-blind crossover study comparing single-dose placebo, 5 mg desloratadine, 10 mg montelukast and the combination administered 2 h prior to allergen inhalation challenge. Methacholine challenges were performed 24 h before and after allergen challenge. Exhaled nitric oxide measurements and sputum inflammatory cell counts were also carried out. All active treatments significantly decreased the late asthmatic response area under the curve. Combination therapy provided the greatest inhibition compared to desloratadine and montelukast. Montelukast was nonsignificantly better than desloratadine but not as effective as the combination. There was a trend towards a decrease in airway responsiveness following montelukast and combination. Montelukast, but not desloratadine or the combination, decreased exhaled NO levels 24 h after allergen. The allergen-induced increase in sputum eosinophil numbers was significantly suppressed at 7 h with desloratadine and combination therapy, and at 24 h with montelukast and combination therapy. Single-dose co-administration of desloratadine and montelukast 2 h prior to allergen inhalation clinically abolished the late asthmatic response and eosinophil recruitment.

Once-daily sublingual allergen-specific immunotherapy improves quality of life in patients with grass pollen-induced allergic rhinoconjunctivitis: a double-blind, randomised study.

The effect of sublingual immunotherapy on quality of life (QoL) was examined in patients with grass pollen-induced rhinoconjunctivitis. Patients (n = 855) were randomised to once-daily grass allergen tablets (2,500; 25,000; or 75,000 SQ-T Phleum pratense extract; GRAZAX or placebo. Treatment was initiated 8 weeks before the start of the grass pollen season and continued throughout. If symptoms were present, patients received loratadine or placebo rescue medication. There were three major findings: in patients using loratadine, grass allergen tablets provided QOL benefits over placebo; Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) score was 17% (p = 0.006) and 20% (p = 0.020) greater with 75,000 SQ-T tablet than with placebo at first and second seasonal visit, respectively; in patients not using loratadine, grass allergen tablets improved QoL more than placebo; RQLQ score was 21% greater (p = 0.021) with 75,000 SQ-T tablet at second seasonal visit; grass tablets (without loratadine) had a greater effect on QoL than loratadine alone. RQLQ score was 26% (p = 0.014) greater with 75,000 SQ-T tablets than loratadine at second seasonal visit. These data show that sublingual immunotherapy with grass allergen tablets improves QOL in allergic rhinoconjunctivitis, reduces symptoms, and that this effect is greater than rescue antihistamine alone.

Desloratadine inhibits constitutive and histamine-stimulated nuclear factor-kappaB activity consistent with inverse agonism at the histamine H1 Receptor.

BACKGROUND: The human histamine H1 receptor is constitutively active and exhibits basal activation of nuclear factor-kappaB (NF-kappaB), an important modulator of allergic inflammation. Certain H1 antihistamines have recently been shown to inhibit basal NF-kappaB activity by stabilizing the H1 receptor in an inactive state, a phenomenon called 'inverse agonism'. METHODS: We evaluated the effect of the new H1 antihistamine, desloratadine, on basal and histamine-stimulated NF-kappaB activity and compared it with the activities of other H1 antihistamines. RESULTS: Transiently transfected COS-7 cells co-expressing NF-kappaB-luciferase and the H1 receptor exhibited constitutive NF-kappaB activity. H1 antihistamines reduced basal NF-kappaB activity (rank order of potency: desloratadine > pyrilamine > cetirizine > loratadine > fexofenadine). Histamine stimulated basal NF-kappaB activity 8-fold, which was blocked by H1 antihistamines (rank order of potency: desloratadine > cetirizine > pyrilamine > loratadine > fexofenadine). Neither histamine nor antihistamines had any effect on NF-kappaB activity in the absence of the H1 receptor. CONCLUSIONS: Desloratadine, acting through the histamine H1 receptor, inhibited basal NF-kappaB activity and can thus be classified as an inverse agonist. Inhibition of basal and histamine-stimulated NF-kappaB activity may help to explain previously reported inhibitory effects of desloratadine on allergic inflammatory mediators.

Anti-inflammatory properties of desloratadine.

BACKGROUND: Allergic rhinitis (AR) is associated with robust infiltration of immune cells and mediators that may contribute to clinical manifestations of the disease. OBJECTIVE: To review the complex immune effector mechanisms involved in the allergic response and discuss their effects on the pathophysiological and clinical manifestations of AR. Desloratadine, a novel antihistamine, was used as a probe with the goal of attaining a better understanding of the inflammatory processes underlying the allergic response. METHODS: Data were obtained from abstracts and peer-reviewed journals. The pathophysiology of the allergic response has been extensively studied. This paper presents only data from studies that used desloratadine at physiologically relevant concentrations. RESULTS: Key mediators involved in the allergic response and in pathophysiological and clinical manifestations of the immune response were reviewed. Desloratadine was used as a probe to further elucidate the mechanisms involved during an allergic response. CONCLUSIONS: Some have proposed a link between the pathophysiology of AR and the clinical manifestation of symptoms. Desloratadine, a new-generation antihistamine, has demonstrated anti-inflammatory effects in vitro; indeed, desloratadine is capable of intervening at various points in the immune cascade. Although in vitro results do not necessarily correlate with clinical efficacy, the anti-inflammatory properties of desloratadine may contribute to its efficacy in patients with AR, allergy-induced asthma, and other related allergic conditions. Antihistamines that modulate in the immune system at various stages may optimize treatment of allergic disease.