Ara h 2 and Ara 6 are the best predictors of severe peanut allergy: a double-blind placebo-controlled study.

BACKGROUND: Component-resolved diagnostics offers a modern tool in peanut allergy, but studies applying consistently double-blind placebo-controlled challenges are lacking. We aimed to optimize diagnostics for moderate-to-severe peanut allergy in a birch-endemic region and to create an oral-peanut challenge with its allergen activity characterized. METHODS: We performed double-blind placebo-controlled peanut challenges for a referred sample of 6- to 18-year-olds with peanut sensitization or a high suspicion of peanut allergy, including anaphylaxis. We measured specific IgE (sIgE) to Ara h 1, 2, 3, 6, 8, and 9. Testing of allergen activity of the challenge products was by IgE microarray inhibition. RESULTS: Of the 102 patients, 69 were challenge positive: 25 (36%) had severe, 36 (52%) moderate, and 8 (12%) mild symptoms; 38 (37%) received adrenalin. SIgE to Ara h 6 AUC 0.98 (95%CI, 0.96-1.00) was the best marker of moderate-to-severe allergy. When sIgE to Ara h 2 and Ara h 6 was measured together, all (100%) severe reactions at low doses were successfully diagnosable. SIgE to Ara h 8 had no diagnostic value, AUC 0.42 (95%CI, 0.30-0.52). Both nonroasted and roasted peanut inhibited 100% of IgE binding to Ara h 1, 2, 3, and 6. Nonroasted peanut inhibited 87% of IgE binding to Ara h 8, roasted inhibited 30%. The products lacked Ara h 9 activity. CONCLUSION: Co-sensitization to Ara h 2 and Ara h 6 was associated with severe reactions distinguishing severe allergy from mild symptoms. SIgE to Ara h 8 added no diagnostic value. Component-resolved diagnostics reduce the need for oral challenges in peanut allergy.

Use of a common food frequency questionnaire (FFQ) to assess dietary patterns and their relation to allergy and asthma in Europe: pilot study of the GA2LEN FFQ.

BACKGROUND/OBJECTIVES: Comparable international data on food and nutrient intake is often hindered by the lack of a common instrument to assess food intake. The objective of this study was within the Global Allergy and Asthma European Network of Excellence (GA(2)LEN), we developed and piloted a food frequency questionnaire (FFQ) to assess its validity in Europe. SUBJECTS/METHODS: Five countries participating in GA(2)LEN took part in the pilot study. A total of 200 adults aged 31-75 years were invited to complete a FFQ in two occasions and to give a blood sample. The intra-class correlation coefficient (ICC) was used to assess repeatability of the FFQ. Plasma phospholipid fatty acids (FAs) were analysed by gas chromatography. Pearson correlation was used to analyse the correlation between estimated dietary FA intake and plasma phospholipid FA levels. RESULTS: A total of 177 participants (89%) had complete data on FFQ(1) and plasma phospholipid FAs. In all, 152 participants (76%) completed both FFQs. ICCs between macronutrients ranged from 0.70 (saturated FAs) to 0.78 (proteins) and between 0.70 (retinol) and 0.81 (vitamin D) for micronutrients. Dietary n-3 FAs showed a good correlation with total plasma phospholipid n-3 FAs and with docosahexaenoic acid in the whole sample (0.40) and in individual countries. Poor correlations were observed for other FAs. CONCLUSIONS: The GA(2)LEN FFQ is an appropriate tool to estimate dietary intake for a range of nutrients across Europe regardless of cultural and linguistic differences. The FFQ seems to be useful to estimate the intake of n-3 FAs but not other FAs.