Anaphylaxis is a serious systemic allergic reaction with rapid onset and potentially life-threatening. We report in detail a case of severe nocturnal anaphylaxis due to pigeon tick bite showing the diagnostic value of the extract and the recombinant allergen in the diagnostic procedures (basophil activation test, IgE immunoblot, and experimental ImmunoCAP). Apart from the presented case, we describe that during the last 10 years, we have collected 28 cases of allergy to Argas reflexus from several European countries. We suspect that this allergy is underdiagnosed because of the lack of diagnostic reagents. Because of the growing number of pigeons in Middle and Southern Europe cities, some cases of idiopathic anaphylaxis could potentially be caused by A. reflexus in those countries. The identification of pigeon ticks as a trigger of anaphylaxis would greatly improve medical care and advice for these patients as the parasite can be exterminated by eradication measures to avoid further incidents.

BackgroundThe exact mechanism of systemic hypersensitivity to venom is not exactly understood. It is suggested T cells with regulatory potential can downregulate other T cell subsets and effector cells, ex. mast cell or basophils. We focused on relationship of specific basophil reactivity in relationship to proportion of regulatory T cells.MethodsForty-five patients with history of systemic symptoms of allergy to Hymenoptera venom were included. Basophil reactivity before the treatment and after one year of allergen immunotherapy (AIT) was measured by CD63 expression, CD203c marker used for basophil identification. Cells were stimulated by aqueous solution of allergen in concentration range 0.01 to 1 μg/mL. T regulatory cells were identified as CD4 positive, CD25 bright and CD127 negative at the same interval of treatment. Monoclonal antibodies conjugated with fluorochromes were used, measured by FACSCalibur. Paired t test and correlation analysis used for statistical evaluation.ResultsMedian Treg proportion before therapy was 2.160, after IT 1.960, basophil specific response (proportion of CD63 positive cells) at the same interval were 3.65 and 4.11 at 0.01 μg/mL, 13.1 and 16.1 for 0.1 μg/mL and 33.85 and 40.8 for 1 μg/mL. All differences were not statistically significant. Differences of basophil activation were not significantly related to proportion of T regulatory cells.ConclusionsIn our group of patients with HV allergy, treated by AIT, we did not found any relationship between basophil specific activation during allergen immunotherapy and proportion of T regulatory cells.

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