Validation of a commercial allergen microarray platform for specific immunoglobulin E detection of respiratory and plant food allergens.

BACKGROUND: As the use of multiplex-specific immunoglobulin E (sIgE) detection methods becomes increasingly widespread, proper comparative validation assessments of emerging new platforms are vital. OBJECTIVE: To evaluate the clinical and technical performance of a newly introduced microarray platform, Allergy Explorer (ALEX) (MacroArray Diagnostics), in the diagnosis of pollen (cypress, grass, olive), dust mite (Dermatophagoides pteronyssinus), mold (Alternaria alternata), fruit (apple, peach), and nut (walnut, hazelnut and peanut) allergies and to compare it with those of the ImmunoCAP Immuno Solid-phase Allergen Chip (ISAC) 112 microarray and the ImmunoCAP singleplex method (ThermoFisher Scientific). METHODS: We enrolled 153 patients with allergy and 16 controls without atopy. The sIgE assays were conducted using ISAC112, ALEX version 2 (ALEX2), and ImmunoCAP for whole extracts and major components. Technical validation of ALEX2 was performed by measuring repeatability and interassay, interbatch, and interlaboratory reproducibility. RESULTS: When measured globally (detection by 1 or more allergen components), ALEX2 had adequate sensitivity and specificity for most of the allergens studied, comparable in general with that of ISAC112 (except for olive pollen and walnut) and similar to that of ImmunoCAP whole extract measurements. Component-by-component analysis revealed comparable results for all techniques, except for Ole e 1 and Jug r 3, in both ISAC112 and ImmunoCAP comparisons, and Alt a 1, when compared with ISAC112. Continuous sIgE levels correlate with sIgE by ImmunoCAP. Good reproducibility and repeatability were observed for ALEX2. CONCLUSION: ALEX2 has sound technical performance and adequate diagnostic capacity, comparable in general with that of ISAC112 and ImmunoCAP.

Efficacy and Safety of Omalizumab (Xolair) for Cholinergic Urticaria in Patients Unresponsive to a Double Dose of Antihistamines: A Randomized Mixed Double-Blind and Open-Label Placebo-Controlled Clinical Trial.

BACKGROUND: Cholinergic urticaria (UCOL) is a highly disabling inducible urticaria triggered by an increase in core body temperature. OBJECTIVE: To explore the safety and efficacy of omalizumab in controlling UCOL. METHODS: We conducted a multicenter randomized mixed double-blind and open-label (first 4 months blinded followed by 8 months open-label) placebo-controlled clinical trial in 22 patients suffering from UCOL who were unresponsive to a double dose of antihistamines. We performed an exercise challenge test during each visit as our main outcome variable. RESULTS: The overall rate of exercise challenge test negative at week 48 was 31.3%, with an average increase in exercise challenge test negative rate of 2.9% points (95% CI, 1.5-4.2) per visit. Statistically significant differences in the negative exercise challenge test rate between the placebo and active intervention groups were not observed during the blinded period (first 4 months of the study). However, from the fourth dose, a progressive improvement was observed. When comparing before and after treatment, statistically significant improvements in all secondary outcome measures were noted after 4 doses (UCOL score: P = .0015; visual analog scale score: P = .0108; days with symptoms: P = .0125) and after 8 doses (UCOL score: P = .0005; chronic urticaria quality of life questionnaire: P = .0105; visual analog scale score: P = .0008; and days with symptoms: P = .0144). In the follow-up visit after the cessation of treatment, the symptoms reappeared, with positive exercise challenge test result and significant increases in all variables. Only 4 of 22 patients remained asymptomatic after 3 months of no treatment. No adverse effects were reported. CONCLUSIONS: This randomized mixed double-blind and open-label placebo-controlled trial showed evidence of the safety and potential efficacy of omalizumab in patients with UCOL.

Molecular sensitization patterns and influence of molecular diagnosis in immunotherapy prescription in children sensitized to both grass and olive pollen.

BACKGROUND: The overlapping grass and olive pollen seasons in Spain and the phenomenon of cross-reactivity can make it difficult to determine the true causative agent of seasonal allergic rhinitis when only skin prick tests with whole extracts are used. The aim of the GRAMOLE study was to determine sensitization patterns to the major grass and olive pollen allergens detected using specific recombinant IgE and to explore how this knowledge affected physicians' choice of allergen-specific immunotherapy. METHODS: Epidemiological, observational, multicenter, cross-sectional study. Results from children under 18 years of age diagnosed with seasonal allergic rhinitis by positive skin prick tests to olive and grass pollen were analyzed. Specific IgE to Phl p 1+5, Ole e 1, and Phl p 7+12 was determined. Investigators specified the optimal composition of allergen immunotherapy before and after knowing the results of the molecular diagnosis. RESULTS: A total of 281 patients with a mean age of 13.4 years were included. Double sensitization to both major allergens was found in vitro in 76% of children for an IgE cutoff point of 0.35 kU/L. When the molecular diagnosis results were known, specialists changed the composition of the prescribed immunotherapy in 52.87% of cases. CONCLUSIONS: Double sensitization to grass and olive pollen is common in Spain and also occurs in the pediatric population. Molecular diagnosis using specific IgE may help improve immunotherapy selection in polysensitized patients.

Comparison of conventional and component-resolved diagnostics by two different methods (Advia-Centaur/Microarray-ISAC) in pollen allergy.

BACKGROUND: Component-resolved diagnostics (CRD) has recently been introduced into clinical allergology. OBJECTIVE: The aim of this study was to assess the contribution that this new diagnostic technique makes to conventional diagnosis in patients with pollen allergy, comparing CRD with conventional technologies, and to compare 2 CRD methods, Advia-Centaur and Microarray-ISAC. METHODS: Serum samples from 120 pollen-allergic patients were obtained. Immunoglobulin (Ig) E to total extracts (CAP System) and individual allergens using both CRD methods were determined. RESULTS: The 3 diagnostic methods were in agreement in 62.5% of cases. In 30%, the CRD modified the conventional diagnosis either by detecting new relevant sensitizations (mainly to Olea) or by ruling out clinically irrelevant sensitizations caused by panallergens. The main differences between the 2 CRD methods were the deficiency in the ISAC version we used (ISAC-CRD-89) to detect sensitizations to Salsola and Plantago and that Advia-Centaur did not detect sensitizations to cypress. For all allergens except for Par j 1, a significant association in the frequency of sensitization was seen with the 2 CRD techniques and good agreement when comparing the results of the 2 methods in all cases. Significant correlation was found in the concentration of specific IgE in the 2 techniques for the most prevalent allergens in our setting. The results of the different profilins analyzed using Microarray-ISAC were superimposable although somewhat lower in the case of Phl p 12. CONCLUSIONS: Component-resolved diagnostics modified the conventional diagnosis in 30% of cases. The results from the 2 CRD methods showed good agreement and correlation for most allergens.

Double-blind, placebo-controlled Alternaria alternata immunotherapy: in vivo and in vitro parameters.

Few studies have been published on the efficacy and safety of immunotherapy with fungal extracts, possibly because of difficulties arising from antigenic variability among different strains of fungus. The aim of the study was to analyze changes in the in vivo and in vitro parameters in response to immunotherapy with an Alternaria alternata extract. We studied 28 patients with rhinitis, bronchial asthma, or both caused by Alternaria. The patients were randomized to the active immunotherapy or placebo group, and a conventional schedule of immunotherapy was used. We recorded changes for a year in skin reactivity (skin prick test), conjunctival reactivity (conjunctival provocation test), and in vitro parameters (serum-specific IgE, IgG, IgG1 and IgG4 for A. alternata complete extract and for natural and recombinant Alt a 1). Twenty-three patients completed the study and all attained the maintenance dose. There were no changes in skin reactivity in the active treatment group, and reactivity increased at the end of the study period in the placebo group. Conjunctival sensitivity decreased only in the active treatment group when the maintenance dose was reached. Allergen-specific IgE decreased, and IgG, IgG1 and IgG4 increased in all periods of study in the active treatment group, with no changes in the placebo group. Allergen-specific immunotherapy with the A. alternata extract tested here led to a decrease in conjunctival reactivity and induced a significant immunologic response.

Double-blind comparative study of cluster and conventional immunotherapy schedules with Dermatophagoides pteronyssinus.

BACKGROUND: The conventional schedule for subcutaneous immunotherapy with allergen extracts, although efficacious and safe, is slow during the dose-increase phase. OBJECTIVE: We sought to compare the efficacy and safety of subcutaneous immunotherapy with Dermatophagoides pteronyssinus standardized extract given in a 6-week cluster period and a conventional 12-week schedule during the incremental-dose phase. METHODS: Of 239 patients with rhinitis, allergic bronchial asthma, or both caused by D pteronyssinus , 120 were randomly assigned to the cluster schedule, and 119 were randomly assigned to the conventional schedule. A biologically standardized D pteronyssinus depot extract (ALK-Abelló S.A., Madrid, Spain) was administered in a placebo-controlled, double-blind fashion during the initial phase of cluster or conventional treatment. We recorded adverse reactions, clinical efficacy, cutaneous reactivity, and serum specific immunoglobulins to D pteronyssinus before immunotherapy, when the maximum dose was reached in the cluster and conventional schedules, and after 1 year of treatment. RESULTS: The cluster schedule reduced the time to maintenance dose by 46% and caused systemic adverse reactions (all mild) after only 0.15% of injections, with no differences in comparison with the conventional schedule. Cluster immunotherapy led to decreases in asthma and rhinitis symptoms, reduced the cutaneous reactivity, and produced the increase in specific IgE and IgG 4 levels on reaching the maintenance dose in the sixth week, 6 weeks earlier than with the conventional schedule. CONCLUSION: The cluster schedule for the initial phase of immunotherapy with incremental doses of D pteronyssinus is a safe alternative to conventional immunotherapy and offers the further advantage of achieving clinical and immunologic improvements sooner.