Table 1.
Study characteristics.
| Study Information | Study Design | Relevant Study Population | Method of Intervention | Method of Outcome Measurement | Outcomes Reported |
|---|---|---|---|---|---|
| Oral Immunotherapy | |||||
| Bouvier et al.; Lyon hospital allergy clinic (F); 1 May 2012–1 February 2013 [21] | NS, comparison of participants’ allergic reactions before and after oral immunotherapy | 52 subjects (age 8–63 years; 17% <18 years) with IgE-sensitisation to birch pollen and apple; and OAS to Rosaceae foods according to history | All subjects underwent oral immunotherapy with increasing doses of fresh Golden Delicious (GD) apple. 1. Initial dose escalation with nine doses from 0.1 mg to 16 g. Portion increased every 20–30 min. 2. Build-up phase starting at 16 g and increasing to half an apple (64 g) 3 times per week up until 24 weeks after start. 3. Maintenance phase consisting of half an apple 3 times a week up until 48 weeks after start. |
Patient history at 48 weeks follow-up | 1. Number of subjects that achieved tolerance of 64 g of apple after 48 weeks. 2. Number of subjects that was tolerant to other Rosaceae fruits after oral immunotherapy with apple. |
| Kopac et al.; University hospital Bern allergy clinic (CH); December 2009–August 2010 [22] | RCT | 40 subjects (age 18–61 years) with IgE-sensitisation to birch pollen and Mal d 1; and challenge-confirmed OAS to Golden Delicious apple | 27 of 40 subjects underwent oral immunotherapy with increasing doses of fresh Golden Delicious (GD) apple. 1. Initial dose escalation with doses from 1 g to 128 g. Portion doubled every 5 min. 2. Build-up phase starting at the largest dose tolerated in the preceding phase to whole apple (150–200 g). Portion doubled every 2–3 weeks. 3. Maintenance phase commencing when a whole apple was tolerated (average 20 weeks) and consisting of at least three apples per week up until 8 months after the start. 13 of 40 subjects remained untreated and formed the control group. |
Patient history at 8 months follow-up | 1. Proportion of subjects that achieved tolerance to 128 g of apple after 8 months. 2. Number of subjects that achieved cross-tolerance to other birch pollen cross-reacting fruits/nuts after oral immunotherapy with apple. |
| (Heat) Processing | |||||
| Ballmer-Weber et al.; University hospital Zurich allergy clinic (CH); January 2000–February 2001 [23] | NS, comparison of participants’ allergic reactions to processed and unprocessed variants of the food | 12 subjects (age 21–42 years) with IgE- sensitisation to birch pollen (and mugwort pollen in 9/12 subjects) and celery; and allergic reactions to celery according to history | 1. Cook celery (110 °C; 15 min) 2. Dehydrate celery (celery spice) |
Comparison of DBPCFC with processed celery (12 of 12 subjects) to DBPCFC with raw celery (10 of 12 subjects) or convincing history to raw celery (2 of 12 subjects) | 1. Number of subjects with symptoms in response to oral challenge with cooked celery and celery spice 2. Type of symptoms 3. Dose eliciting symptoms |
| Bohle et al.; Hannover Medical School Department of Dermatology and Allergology (D); time NS [24] | NS, comparison of participants’ allergic reactions to processed and unprocessed variants of the food | 5 subjects (age 5–37 years; 20% <18 years) IgE-sensitised to birch pollen with OAS and worsening of atopic dermatitis to carrot, celery or apple according to history | Celery (1 of 5 subjects): boil until soft Carrot (3 of 5 subjects): boil until soft Apple (1 of 5 subjects): pasteurisation (juice) |
Comparison of DBPCFC with processed food (4 of 5 subjects) or convincing history to processed food (1of 5 subjects) to DBPCFC with raw food (5 of 5 subjects) | 1. Number of subjects with OAS in response to oral challenge with cooked carrot or celery or apple 2. Type of symptoms |
| Hansen et al.; University hospital Copenhagen (DK), and University hospital Zurich allergy clinics (CH); 1998–2000 [25] | NS, comparison of participants’ allergic reactions to processed and unprocessed variants of the food | 17 subjects (age 14–65 years) with IgE-sensitisation to birch pollen and hazelnut; and OAS to hazelnut according to history or challenge | Roast hazelnut (140 °C; 40 min) | Comparison of DBPCFC with roasted hazelnut (17 of 17 subjects) to DBPCFC with raw hazelnut (16 of 17 subjects) or convincing history to raw hazelnut (1 of 17 subjects) | 1. Number of subjects with symptoms in response to oral challenge with roasted hazelnut 2. Type of symptoms 3. Dose eliciting symptoms |
| Worm et al.; University hospital Charité Berlin dermatology outpatient clinic (D); time NS [26] | NS, comparison of participants’ allergic reactions to processed and unprocessed variants of the food | 82 of 132 included subjects (age 21–65 years) with IgE-sensitisation to birch pollen and hazelnut; and challenge-confirmed hazelnut allergy | Roast hazelnut (144 °C; time unknown) | Comparison of DBPCFC with roasted hazelnut (20 of 82 subjects) to DBPCFC with raw hazelnut (82 of 82 subjects) | 1. Number of subjects with symptoms in response to oral challenge with roasted hazelnut 2. Type of symptoms 3. Dose eliciting symptoms |
| Consumption of Hypoallergenic Cultivars | |||||
| Asero et al.; setting NS; 2004 [27] | NS, comparison of participants’ allergic reactions to low and high allergenic cultivars | 7 of 17 included subjects (age 26–49) with sensitisation to birch pollen and apple; and OAS to apple according to history | Consumption of low allergenic G-198 or Orim apple | Comparison of SBFC with G-198 apple (6 of 7 subjects) or Orim apple (1 of 7 subjects) to SBFC with Golden Delicious apple | 1. Mean symptoms severity score for OAS (Score 0–100) 2. Number of subjects reporting NO symptoms in response to oral challenge |
| Bolhaar et al.; University Medical Centre Utrecht department of dermatology and allergology (NL); time NS [28] | NS, comparison of participants’ allergic reactions to low and high allergenic cultivars | 5 of 23 included subjects (age > 18 years) with a history of rhinoconjunctivitis during birch pollen season, sensitisation to apple, and OAS to apple according to history | Consumption of low allergenic Santana apple | Comparison of DBPCFC with Santana apple to DBPCFC with Golden Delicious apple | 1. Mean symptom severity score for OAS (VAS 0–100) 2. Quantities needed to provoke similar VAS score for Santana apples as for Golden Delicious apples |
| Kootstra et al.; University Medical Centre Groningen allergy outpatient clinic (NL); February–May 2005 [29] | NS, comparison of participants’ allergic reactions to low and high allergenic cultivars | 15 subjects (age > 18 years) with sensitisation to birch pollen and apple; and challenge-confirmed OAS to apple | Consumption of low allergenic Santana apple | Comparison of SBFC with Santana apple to SBFC with Golden Delicious apple as a positive control and SBFC with Topaz apple as a negative control | 1. Maximum symptom severity score (VAS, range not described) at dose 1. 2. Number of subjects reporting NO symptoms in response to oral challenge. |
| Vlieg-Boerstra et al.; University Medical Centre Groningen allergy outpatient clinic (NL); 2006–2008 [30] | NS, comparison of participants’ allergic reactions to low and high allergenic cultivars | 33 subjects (age 18–52 years) with sensitisation to birch pollen in 32/33 subjects; and challenge-confirmed OAS to apple |
Consumption of low allergenic Elise, Santana and Pink Lady apples | Comparison of SBFC with Elise, Santana, Pink Lady and Golden Delicious apple | 1. Cumulative symptom severity score (VAS, range not described) at dose 1. 2. Number of subjects reporting NO symptoms in response to oral challenge. |
F = France, CH = Switzerland, D = Germany, DK = Denmark, NL = The Netherlands; NS = not specified; RCT = Randomised controlled trial; OAS = oral allergy syndrome; DBPCFC = double-blind placebo-controlled food challenge; SBFC = single-blind food challenge; VAS = Visual analogue scale.