Double‐blind, placebo‐controlled food challenge with apple

Abstract

The aim of the study was to develop and evaluate different methods of double-blind, placebo-controlled food challenge (DBPCFC) with apple. Three different DBPCFC models were evaluated: fresh apple juice, freshly grated apple, and freeze-dried apple powder. All challenges were performed outside the pollen season and took place from 1997 to 1999. The freeze-dried apple material was characterized by means of leukocyte histamine release (HR), skin prick test (SPT), and immunoblotting experiments. The study population consisted of birch pollen-allergic patients with a history of rhinitis in the birch-pollen season and positive specific IgE to birch. For comparison of the DBPCFC models, 65 patients with a positive open oral challenge with apple were selected. In the characterization of the freeze-dried apple material, 46 birch pollen-allergic patients were included. The IgE reactivity to apple was evaluated by measurement of specific IgE, HR, and SPT. Golden Delicious apples were used in all experiments. The results of this study showed that it was possible to perform DBPCFC with apple in birch pollen-allergic individuals. The model with freshly squeezed apple juice had a low sensitivity and displayed a high frequency of reactions to placebo, probably due to the ingredients used for blinding. The sensitivity of the models with freshly grated apple and freeze-dried apple powder was 0.74/0.60. An increase in sensitivity is desirable. The freeze-dried apple powder proved to be useful for SPT, HR, and oral challenges, but further investigation of the stability and the allergenic profile of the material is needed.

Standardization of food challenges in patients with immediate reactions to foods – position paper from the European Academy of Allergology and Clinical Immunology

“…In cases with very stable foods such as peanut or cod (42,71) stability in the serving is not a problem, whereas in other cases especially with foods of vegetable origin (apples) the stability is very low (72). The procedures must be adjusted according to the stability of the food in question (35,37).…”

Can we help people with Oral Allergy Syndrome eat fresh fruit?

“…Our work suggested that despite their reputation as the "gold standard" test, open studies showing improvement in tolerance to apple, whilst another two studies, one of which was blinded, showed no difference in the ability to tolerate apple before and after treatment (128)(129)(130)132,144). Due to the contradictory results a study utilising more robust methodology was felt to be necessary to determine the efficacy of BP-SIT in the treatment of pollen food syndrome.…”

“…Some studies have used objective symptoms as a cut off point for testing, including blistering of the oral mucosa, a drop in blood pressure or a fall in forced expiratory volume in 1 second (FEV 1 ) (145). Other studies have used a three point scoring system where zero was equal to no symptoms and three corresponded to the most pronounced symptoms (144).…”

Anaphylaxis from Mandarin <i>(Citrus reticulata)</i>: Identification of Potential Responsible Allergens

“…Challenge tests are hampered by several ethical (risk of anaphylaxis) [18, 19] as well as practical issues (e.g. correct preparation and blinding) [20, 21]. …”