Themes in allergy

Optimization of Basophil Activation Test in the Diagnosis and Qualification for Allergen-Specific Immunotherapy in Children with Respiratory Allergy to the House Dust Mite Dermatophagoides pteronyssinus

The aim of this study was to optimize a basophil activation test in the detection of allergy to the house dust mite Dermatophagoides pteronyssinus in children with allergic respiratory diseases. This study involved 32 cases, 13 girls and 19 boys aged 4-17 years, with perennial asthma or allergic rhinitis caused by D. pteronyssinus. The control group consisted of 13 girls and 19 boys aged 4-17 years with seasonal allergic asthma or rhinitis provoked by Timothy or birch pollen. House dust mite (HDM) allergy was excluded in the controls based on their medical history, skin prick test (SPT) results and sIgE determination. In all patients, a basophil activation test (BAT) was performed with five dilutions of D. pteronyssinus allergen (the dilution series ranged from 22.5 to 0.00225 ng/mL). The results were analyzed by using the receiver operating characteristics (ROC) to determine the optimal allergen concentrations, outcome measures and cut-off points that would differentiate most accurately between HDM-allergic and non-allergic patients. As a "gold standard", criteria for allergen-specific immunotherapy with D. pteronyssinus or respective pollens were applied by an experienced pediatric allergist following the guidelines of the European Academy of Allergy and Clinical Immunology. The highest diagnostic efficiency was yielded by the protocol assuming a cut-off value of 9.76% activated basophils after activation with a single allergen concentration of 2.25 ng/mL (sensitivity 90.6%, specificity 100%). This protocol yielded 3 (4.7%) misclassifications, all false negative, when compared with the "gold standard". There was a strong correlation with the BAT results at 22.5, 2.25 and 0.225 ng/mL (respectively r = 0.90 and r = 0.78, p < 0.001), as well as between the BAT at 2.25 ng/mL and SPT (r = 0.82, p < 0.001) and between the SPT and sIgE levels (r = 0.78, p < 0.001). High cross-reactivity between D. pteronyssinus and D. farinae was confirmed based on the BAT at 22.5 ng/mL (r = 0.82, p < 0.001). In conclusion, the BAT showed very good concordance with the result of a meticulous process of decision-making that combined validated allergy tests (SPT, sIgE) with expert guidelines, specialist knowledge and experience. Facing the risk of the incorrect qualification of patients for costly, long-lasting and potentially risky allergen-specific immunotherapy, the inclusion of a basophil activation test into diagnostic process seems fully justified.

Efficacy and Safety of Subcutaneous Allergen-Specific Immuno-Therapy in Horses with Allergic Cutaneous and Respiratory Diseases-A Systematic Review

Allergen-specific immunotherapy (AIT) is the only current intervention that has the ability to modify the immune response toward a tolerogenic state. This study aimed to assess the efficacy and safety of AIT in horses with allergic diseases in a systematic manner. Three databases were searched to identify articles reporting clinical outcomes and adverse events associated with AIT. The articles were evaluated for beneficial responses to AIT, defined as a ≥50% reduction in clinical signs, and clinical remission. Horses with respiratory diseases, urticaria, and pruritic dermatitis receiving insect monotherapy or multi-allergen AIT were included. All adverse events were graded, and analytical and confounding biases were assessed. The results showed that multi-allergen AIT had a beneficial response in 75% of horses with respiratory diseases, 88% with urticaria, and 56% with pruritic dermatitis. However, horses treated solely with insect AIT for pruritic dermatitis had a lower response rate (36%). Self-limiting local reactions were the most common adverse events, with systemic reactions grade II accounting for 11% of reported events. Analytical and confounding biases were identified as major limitations in the available studies. Further research is needed to address these biases and provide stronger evidence on the efficacy and safety of AIT in horses with allergic diseases.

Predictive factors for clinical response to allergy immunotherapy in children with asthma and rhinitis

BACKGROUND

To date, no predictive methods for the clinical response to allergy immunotherapy (AIT) are available. We sought to evaluate the pretreatment parameters used in diagnosing allergic asthma and/or rhinitis including allergen skin-prick test responses, serum specific and total IgE (sIgE and tIgE) levels and blood eosinophil counts, and to identify whether these can be used to predict clinical effectiveness in children treated with immunotherapy.

METHODS

This study involved 185 children who had undergone 3 years of standardized-quality house-dust mite subcutaneous immunotherapy. Clinical characteristics and laboratory parameters were analyzed. A multivariate unconditional logistic regression model and receiver operating characteristic curves were used. Predicted probabilities and predictive areas under the curve were calculated.

RESULTS

The clinical response to AIT was effective in 129/185 (69.7%) patients. Four variables were associated with clinical response by multivariate logistic analysis: tobacco smoke exposure [odds ratio (OR) 2.845 and 95% confidence interval (CI) 1.147-7.058; p = 0.024], a family history of atopy (OR 2.881 and 95% CI 1.240-6.692; p = 0.014), a serum tIgE level ≥965 kU/l (OR 5.917 and 95% CI 2.320-15.089; p = 0.000) and an sIgE/tIgE ratio ≥6% (OR 0.336 and 95% CI 0.124-0.911; p = 0.032). The sensitivity and specificity of the area under the curve of the serum tIgE were higher than those of serum sIgE and sIgE/tIgE ratio alone.

CONCLUSION

Tobacco smoke exposure, atopic family history, serum tIgE and sIgE/tIgE ratio were in significant correlation with clinical response to AIT in children, which may be helpful for patient selection before immunotherapy. The serum tIgE is superior to both the serum sIgE/tIgE ratio and sIgE levels alone in predicting clinical effectiveness.

Protection against the allergic airway inflammation depends on the modulation of spleen dendritic cell function and induction of regulatory T cells in mice

Background

Allergen-induced imbalance of specific T regulatory (Treg) cells and T helper 2 cells plays a decisive role in the development of immune response against allergens.

Objective

To evaluate effects and potential mechanisms of DNA vaccine containing ovalbumin (OVA) and Fc fusion on allergic airway inflammation.

Methods

Bronchoalveolar lavage (BAL) levels of inflammatory mediators and leukocyte infiltration, expression of CD_11c⁺CD₈₀⁺ and CD_11c⁺CD₈₆⁺ co-stimulatory molecules in spleen dendritic cells (DCs), circulating CD₄⁺ and CD₈⁺ T cells, Foxp3⁺ in spleen CD₄⁺ T cells and spleen CD₄⁺ T cells were measured in OVA-sensitized and challenged animals pretreated with pcDNA, OVA-pcDNA, Fc-pcDNA, and OVA-Fc-pcDNA.

Results

OVA-Sensitized and challenged mice developed airway inflammation and Th2 responses, and decreased the proliferation of peripheral CD₄⁺and CD₈⁺ T cells and the number of spleen Foxp₃⁺ Treg. Those changes with increased INF-γ production and reduced OVA-specific IgE production were protected by the pretreatment with OVA-Fc-pcDNA.

Conclusion

DNA vaccine encoding both Fc and OVA showed more effective than DNA vaccine encoding Fc or OVA alone, through the balance of DCs and Treg.