Clinical Characteristics and Proposed Wheat-Cofactor Challenge Protocol with a High Diagnostic Yield in Adult-Onset IgE-Mediated Wheat Allergy

Figures & data

Table 1 Inclusion Criteria, Exclusion Criteria, and Contraindications for Wheat Challenge

Inclusion Criteria (All Criteria 1–4 Must be Fulfilled)

Adult patient (age 18–60 years) with the onset of first wheat-allergic symptoms occurring after the age of 18 years

2.Typical IgE-mediated reaction relating to wheat ingestion with at least 1 of the following: Anaphylaxis according to the NIAID/FAAN diagnostic criteria^Citation31 Urticaria, angioedema, generalized erythema, wheezing, or other symptoms compatible with IgE-mediated reaction but not fulfilling the criteria for anaphylaxis

3.Temporal relationship with wheat ingestion with at least 1 of the following: Conventional wheat allergy (WA) with onset occurring within 3 hours after wheat ingestion Wheat-dependent exercise-induced anaphylaxis (WDEIA): an anaphylactic reaction occurring only when the patient exercises within 6 hours after wheat ingestion, but not occurring in the absence of exercise after similar wheat ingestion

4.Positive allergologic workup with at least 1 of the following: SPT to commercial wheat extracts, in-house gliadin, in-house glutenin sIgE to wheat allergens: crude wheat or omega-5 gliadin In the absence of SPTs and sIgE, the patients must have at least 2 episodes of recurrence, the last reaction occurring within 1 year of the time of recruitment

Exclusion criteria

Pregnancy or lactation Unable to provide the clinical history or inability to communicate Previously diagnosed with celiac disease Known allergy to non-steroidal anti-inflammatory drugs Active eosinophilic gastrointestinal diseases in the recent year Participation in any interventional study for the treatment of food allergy Previous or current treatment with allergen immunotherapy during the build-up phase Inability to discontinue antihistamines for initial day escalation, skin testing, or oral food challenges Use of omalizumab, other non-traditional forms of allergen immunotherapy, immunomodulatory therapy (not including corticosteroids), or biologic therapy within the past year Use of investigational drug within 90 days or plan to use the investigational drug during the study period

Contraindications for wheat challenge in our study

History of severe anaphylaxis to wheat resulting in profound hypotension (systolic blood pressure ≤ 50 mmHg), neurological compromise, or respiratory failure

Active cardio-neuro-pulmonary diseases, such as coronary heart disease, asthma, chronic obstructive lung disease, epilepsy, and psychiatric diseases Active urticaria, including acute urticaria from any causes, or recurrence of chronic urticaria within 2 weeks before the challenge

Abbreviations: IgE, immunoglobulin E; NIAID/FAAN, the National Institute of Allergy and Infectious Diseases/Food Allergy and Anaphylaxis Network; sIgE, specific immunoglobulin E; SPTs, skin prick tests.

Figure 1 Summary of modified 3-day challenge protocol.

Abbreviations: ASA, aspirin; g, gram; HR, heart rate; mg, milligram.

Figure 2 Flow diagram of patient recruitment.

Abbreviations: NSAIDs; Non-steroidal anti-inflammatory drugs; IgE, immunoglobulin E.

Table 2 Clinical Characteristics of 33 Patients in Adult-Onset Wheat Allergy Cohort

	All Patients (N=33)	Challenge-Accepted Group (N=18)	Challenge-Denied or Contraindicated Group (N=15)	P-value
Gender
Male	9 (27.3)	4 (22.2)	5 (33.3)	0.697
Female	24 (72.7)	14 (77.8)	10 (66.7)
Age, mean (SD), y	32.6 (11.3)	30.8 (11.6)	34.6 (10.9)	0.339
Wheat allergy phenotype ^a
WDEIA	23 (69.7)	12 (66.7)	11 (73.3)	0.722
WA	10 (30.3)	6 (33.3)	4 (26.7)
Age of onset, mean (SD), y	29.7 (10.5)	28.7 (10.3)	30.9 (10.9)	0.554
Duration of disease, median (range), y	2 (0.25–17)	1.5 (0.25–5)	2 (0.5–17)	0.332*
Atopic history
Allergic rhinitis	17 (51.5)	9 (50.0)	8 (53.3)	0.849
Asthma	2 (6)	1 (5.6)	1 (6.7)	1.0
Atopic dermatitis	2 (6)	1 (5.6)	1 (6.7)	1.0
Non-atopic comorbidities
Chronic urticaria	19 (57.6)	11 (61.1)	8 (53.3)	0.653
Coronary heart disease	2 (6.1)	0 (0.0)	2 (13.3)	0.199
Gastric diseases	5 (15.2)	4 (22.2)	1 (6.7)	0.346
Others	2 (6)	1 (5.6)	1 (6.7)	1.0
Other food allergies	17 (51.5)	10 (55.6)	7 (46.7)	0.611
Shellfish	13 (39.4)	7 (38.9)	6 (40.0)	0.948
Fruits	2 (6.1)	1 (5.6)	1 (6.7)	1.0
Peanut	2 (6.1)	2 (11.1)	0 (0)	0.489
Cow’s milk	1 (3)	1 (5.6)	0 (0)	1.0
Duration from wheat allergy onset to diagnosis, median (range), mo	17 (0.25–60)	11 (0.33–36)	18 (0.25–60)	0.586*
Episodes before recruitment, median (range), n	4 (1–20)	4 (2–12)	4 (1–20)	0.781*
Symptoms according to history
Urticaria	33 (100)	18 (100)	15 (100)	-
Angioedema	21 (63.6)	11 (61.1)	10 (66.7)	0.741
Significant dyspnea	21 (63.6)	14 (77.8)	7 (46.7)	0.064
Chest pain	9 (27.3)	3 (16.7)	6 (40)	0.239
Rhinitis symptoms	6 (18.2)	3 (16.7)	3 (20)	1.0
Syncope	12 (36.4)	5 (27.8)	7 (46.7)	0.261
GI symptoms	9 (27.3)	7 (38.9)	2 (13.3)	0.134
Documented hypotension	7 (21.2)	4 (22.2)	3 (20)	1.0
Cardiac arrest	1 (3)	0 (0.0)	1 (6.7)	0.455
Endotracheal intubation	1 (3)	0 (0.0)	1 (6.7)	0.455
Maximum anaphylaxis severity ^b
Ring & Messmer
Grade 1	2 (6.0)	0 (0.0)	2 (13.3)	0.041
Grade 2	16 (48.5)	12 (66.7)	4 (26.7)
Grade 3	14 (42.5)	6 (33.3)	8 (53.3)
Grade 4	1 (3.0)	0 (0.0)	1 (6.7)
Sampson
Mean (SD)	4.03 (1.16)	4.13 (1.22)	3.80 (1.03)	0.460
Median (range)	4.0 (1.0–5.0)	4.0 (1.0–5.0)	5.0 (2.0–5.0)
EAACI Task Force
Mild	4 (12.1)	1 (5.6)	3 (20.0)	0.056
Moderate	14 (42.4)	11 (61.1)	3 (20.0)
Severe	15 (45.5)	6 (33.3)	9 (60.0)
Allergologic workup
SPT (wheat) ^c	3 (9.1)	2 (11.1)	1 (6.7)	1.0
SPT (gliadin) ^c	28 (84.8)	16 (88.9)	12 (80.0)	0.639
SPT (glutenin) ^c	27 (81.8)	14 (77.8)	13 (86.7)	0.665
sIgE to wheat ^d	20 (60.6)	12 (66.7)	8 (53.3)	0.435
sIgE to ω5- gliadin ^d	29 (87.9)	15 (83.3)	14 (93.3)	0.607
sIgE to wheat level ^d (kAU/L)
Mean (SD)	3.1 (7.3)	4.8 (9.6)	0.98 (1.73)	0.133*
Median (range)	0.44 (0.05–36.8)	0.8 (0.06–36.8)	0.36 (0.05–6.83)
sIgE to ω5- gliadin level ^d (kAU/L)
Mean (SD)	8.56 (12.3)	11.26 (14.9)	5.3 (7.7)	0.303*
Median (range)	3.99 (0.01–50.1)	5.07 (0.01–50.1)	2.07 (0.01–30.5)
Grass sensitization ^e
Any grass	7 (21.2)	7 (38.9)	0 (0)	0.004
Johnson	3 (9.1)	3 (16.7)	0 (0)	0.233
Bermuda	8 (24.2)	8 (44.4)	0 (0)	0.004
Other grain sensitization ^e
Any grain	5 (15.2)	4 (22.2)	1 (6.7)	0.346
Oat	2 (6.1)	1 (5.6)	1 (6.7)	1.0
Rye	2 (6.1)	2 (11.1)	0 (0)	0.489
Barley	2 (6.1)	2 (11.1)	0 (0)	0.489
Millet	0 (0)	0 (0)	0 (0)	-

Notes: All data are presented as N (%) unless otherwise specified. * Comparison median between 2 groups was used Mann Whitney U-test. ^a Indicated by oral wheat ± exercise challenge in challenge-proven cases and indicated by clinical history in patients who did not undergo challenges. ^b Anaphylaxis severity: Ring and Messmer: grade 1–4 ⁽³²⁾, EAACI Task Force on Anaphylaxis⁽³⁴⁾, Sampson severity score^{(33). c} Skin prick test to wheat. (ALK Abello, Hørsholm, Denmark). Histamine phosphate (10 mg/mL) and glycerinated saline were used as the positive and negative controls, respectively; Skin prick test to gliadin and glutenin, using in-house extract.^27,28 Positive test result is defined by a wheal diameter larger than 3 mm compared with the negative control. ^d Allergen-specific IgE using solid-phase immunoassay: ImmunoCAP. Positive test result is defined by a level of allergen-specific IgE ≥ 0.35 kAU/L. ^e Indicated by skin prick tests.

Abbreviations: GI, gastrointestinal; kAU/L, kilo antibody units per liter; SD, standard deviation; SPT, skin prick test; sIgE, specific immunoglobulin E; WA, conventional wheat allergy; WDEIA, wheat-dependent exercise-induced anaphylaxis.

Table 3 Clinical Characteristics of Patients Who Underwent Challenge Procedure

Case	Sex	Age of Onset (Years)	Diagnosis	Symptoms from History	Symptoms During the Challenge	SPT Wheat^a (MWD, mm)	sIgE Wheat^b (kAU/L)	sIgE ω5- gliadin^b (kAU/L)	sIgE LTP ^b (kAU/L)	Total IgE (IU/mL)	Grass Sensitization^c
1	Female	20	WA	U, A, D, GI	U (trunk)	Negative	3.1	50.1	0.01	3420	No
2	Female	35	WA	U, A, D	U (face)	4.5	0.19	1.49	0.12	99.7	Bermuda
3	Female	37	WA	U, A, D, BP	U (face)	Negative	1.33	8.91	0.5	3340	Bermuda
4	Female	18	WA	U, A, GI	GI (2 episodes of emesis)	Negative	4.46	9.06	0.14	1160	Bermuda, Johnson
5	Female	23	WA	U, A, Chest, D, R, GI	U (generalized)	Negative	1.53	27.2	0.06	947	No
6	Male	18	WA	U, A, Chest, D	U (face)	Negative	0.44	3.99	0.01	229	No
7	Female	45	WDEIA	U, A, D, GI	U (face), GI (1 emesis)	Negative	3.1	14.8	0.04	1350	No
8	Female	27	WDEIA	U, Syncope, BP	U (generalized), Facial erythema	Negative	36.8	13.4	0.04	587	Bermuda
9	Female	20	WDEIA	U, D	U (extremities)	Negative	0.28	2.77	0.05	353	No
10	Female	19	WDEIA	U, D	U (face), GI (1 emesis)	Negative	17.1	43.8	0.08	195	Bermuda, Johnson
11	Female	18	WDEIA	U, A, D	U (generalized), A, Facial erythema	Negative	16.7	0.15	0.08	640	Bermuda
12	Male	30	WDEIA	U, Syncope	U (palms, soles)	Negative	0.29	5.62	0	59.6	No
13	Female	21	WDEIA	U, D, GI	U (generalized)	Negative	0.22	1.84	0	24.6	No
14	Female	40	WDEIA	U, D, Syncope, BP	U (face)	Negative	1.09	15.2	0.01	400	No
15	Male	48	WDEIA	U, D, Syncope	U (face)	Negative	0.06	0.18	0	68.5	No
16	Female	21	WDEIA	U, A, D, R, GI	U (Extremities)	Negative	0.43	1.37	NA	82	No
17	Male	40	WDEIA	U, A, Chest, GI, Syncope, BP	U (generalized), BP	Negative	0.54	4.52	0.01	171	No
18	Female	37	WDEIA	U, A, D, R	Negative challenge	3.5	0.28	0.01	NA	211	Bermuda, Johnson

Notes: ^a Skin prick test to wheat. (ALK Abello, Hørsholm, Denmark). Histamine phosphate (10 mg/mL) and glycerinated saline were used as the positive and negative controls, respectively. The positive test result is defined by a wheal diameter larger than 3 mm, compared with the negative control. ^b Allergen-specific IgE using solid-phase immunoassay: ImmunoCAP. ^c Documented by skin prick tests.

Abbreviations: A, angioedema; BP, objective hypotension; C, significant chest pain; D, dyspnea; GI; gastrointestinal symptoms (nausea, vomiting, abdominal pain); R, rhinitis symptoms (rhinorrhea, nasal congestion, sneezing, itchy nose); IU/mL, international units per milliliter; kAU/L, kilo antibody units per liter; LTP, lipid transfer protein; MWD, mean wheal diameter; NA, not applicable; SD, standard deviation; SPT, skin prick test; sIgE, specific immunoglobulin E; WA, conventional wheat allergy; WDEIA, wheat-dependent exercise-induced anaphylaxis.

Figure 3 Outcomes of modified 3-day challenge protocol.

Abbreviations: ASA, aspirin; EIA, exercise-induced anaphylaxis; WA, wheat allergy; WDEIA, wheat-dependent exercise-induced anaphylaxis.

Table 4 Comparison of Wheat-Cofactor Challenge Protocols in Patients with Wheat Allergy

Studies	Cofactors				Positive Challenge Rate
	Allergen Used	Aspirin (mg)	Alcohol	Exercise
Our study	Wheat 60–75 g	300	NA	Yes	Wheat alone 35%
					Wheat+ASA+exercise 94%
Christensen et al 2019^Citation12	Gluten 8–80 g	1000	37.5 % vodka	Yes	Gluten alone 48%
					Gluten+Alcohol 56%
					Gluten+ASA 84%
					Gluten+Exercise 92%
					Gluten+ASA+Exercise 82%
Brockow et al 2015^Citation21	Gluten 10–80 g	500–1000	4.75–14.25% ethanol	Yes	Gluten alone 25%
					Gluten+Exercise 33%
					Gluten+ASA+Alcohol 100%

Abbreviations: ASA, aspirin; g, gram; mg, milligram; NA, not applicable.

Figure 4 Isolated facial urticaria observed during the challenge in patients with adult-onset IgE-mediated wheat allergy. (A) A wheat-allergic patient during the open wheat challenge (day 2). (B) A wheat-dependent exercise-induced anaphylaxis patient during the combined wheat-cofactors challenge (day 3).

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