Pastorello et al. (2000) [465] reported 22 patients (mean age, 28.4 years) with oral allergy syndrome, OAS, (9/22), oedema of the glottis (10/22), urticaria (6/22), dyspnea (3/22), one patient showed asthma and one angioedema and gasterointesinal symptoms. However, there were 4 cases of anaphylatic shock and three of exercise-induced anaphylaxis.

Pastorello et al. (2003) [759] reported symptoms from an additional 7 patients as laryngeal edema (4/7), urticaria(4/7), dyspnea (3/7), cough (2/7), angioedema(2/7), and single occurrences of OAS, rhinitis, asthma, diarrhoea and severe anaphylaxis .

Pasini et al. (2002) [760] report symptoms from 6 patients as urticaria (5/6), OAS (2/6), gasterointesinal symptoms (2/6), and angioedema, rhinoconjunctivitis and asthma (1/6).

Asero et al. (2002) [667] report 4 patients who experienced reactions after ingesting canned corn or salted maize snacks but tolerated "polenta" (a long-boiled cornbread dish).

Figueredo et al. (1999) [796] report a patient with a severe anaphylatic reaction after eating a corn-made snack.

Pauls & Cross (1998) [472] reported a case of food dependent exercise-induced anaphylaxis (FDEIA) to maize (corn) on eating taco (corn) chips, confirmed by challenge. Symptoms began with scalp and facial pruritis, then facial swelling and diffuse urticaria followed by a sensation of throat thickening and dyspnea. The individual was hypotensive with tachycardia. A year later the patient suffered symptoms on eating taco chips without exercise.

Pasini et al. 2002 [760] used commercial extracts, a corn flour extract (in phosphate buffered saline) and the reduced soluble proteins (RSP) fraction, extracted with 50 mM Tris-HCl, pH 7.4 containing 20 mM dithiothreitol from the residue after salt extraction of cornflour.

Figueredo et al. (1999) [796] used commercial extracts and extracted 2 g of the food in 10 ml phosphate buffered saline. After stirring for 60 min at room temperature, the extract was centrifuged at 5000 rpm for 20 min. The supernatant was collected, dialyzed in distilled water, and sterilized by filtration through a membrane of 0.22 µm pore diameter (Millipore, Bedford, MA, USA).

Jones et al. 1995 [832] used extracts prepared by mixing 10 g. of cornflour with 30 ml of phosphate-buffered saline. Samples were mixed on a rocker for 4 hours at 4° C. Mixtures were centrifuged at 2500 X g for 10 minutes, then supernatants were collected and centrifuged at 17,000 X g for 10 minutes. Extracts were sterile-filtered, lyophilized, and stored at 4° C.

Wheal diameters equal to or larger than 3mm were considered as positive in the absence of a reaction to the negative control (Pasini et al. 2002 [760]; Figueredo et al. 1999 [796]).

A positive SPT response was defined as a wheal 3 mm larger than the negative (saline solution) control (Jones et al. 1995 [832]).

Pasini et al. (2002) [760] report 16 patients selected following positive SPT.

Figueredo et al. (1999) [796] report SPT on a single patient.

Pasini et al. (2002) [760] report positive SPT from 16 patients of whom 6 were allergic to corn and 10 tolerant. All 4/4 DBPCFC-positive patients tested reacted positively to the RSP fraction.

Figueredo et al. (1999) [796] found that SPT with beer, barley, malt, wheat, maize, rye, rice, and oat flour were positive but only beer, barley and maize were clinically relevant in one patient.

Pasini et al. (2002) [760] extracted corn flour as described above (SPT) and also extracted cooked polenta by the same methods.

Figueredo et al. (1999) [796] extracted 2 g of the food in 10 ml phosphate buffered saline. After stirring for 60 min at room temperature, the extract was centrifuged at 5000 rpm for 20 min. The supernatant was collected, dialyzed in distilled water, and sterilized by filtration through a membrane of 0.22 µm pore diameter (Millipore, Bedford, MA, USA).

Pasini et al. (2002) [760] used sera from 16 patients.

Pastorello et al. (2000) [465] used sera from 22 patients.

Pasini et al. (2002) [760] report positive CAP (2-4) results for 16 patients of whom 6 were allergic to corn and 10 tolerant.

Pastorello et al. (2000) [465] found that all 22 individuals were CAP positive with the lowest having 0.362 and 0.438 kU/l of specific IgE. The other 20 were from 1.51 to 60.9 kU/l of specific IgE.

Figueredo et al. (1999) [796] detected specific IgE antibodies in the patient's serum against malt (2.88 kU/l), barley (3.86 kU/l), corn (7.18 kU/l), wheat (3.05 kU/l), rye (3.17 kU/l), rice (1.5 kU/l), and oats (12.2 kU/l).

Pasini et al. 2002 [760] separated proteins by 1D SDS-PAGE with 18% acrylamide separating gels. Samples were reduced with mecaptoethanol and heated for 5 min in a boiling water bath before separation.

Pastorello et al. (2000) [465] separated proteins in a discontinuous buffer system with an SDS-PAGE gel (6% stacking gel and a 7.5%-20% separation gradient gel). Maize extract was diluted 1:2 in sample buffer.

Figueredo et al. (1999) [796] used 1D SDS-PAGE with a 5% stacking gel and 15% separating gel. Samples were analysed without reduction.

Pasini et al. 2002 [760] transfered proteins by semidry blotting onto nitrocellulose sheets. Blotted bands were visualized by soaking the membranes for a few minutes in Ponceau S (0.1% (w/v) in 3% (w/v) trichloroacetic acid) and marked with a pencil before destaining with water. Membranes were blocked with tris buffered saline (TBS) containing 0.05% (v/v) Tween 20 (TBS-T) and 5% (w/v) skim milk powder (M-TBS-T) for 2 h, and incubated overnight with single patient sera diluted in TBS-T. After washing five times with M-TBS-T, blots were incubated for 1 h with monoclonal antihuman IgE peroxidase-conjugate antibody (Sigma) diluted 1:5000 (v/v) in M-TBS-T. After four washes in M-TBS-T and one with TBS, bound IgE were visualized by chemiluminescence using the SuperSignal detection kit (Pierce).

Pastorello et al. (2000) [465] electroblotted proteins either onto a nitrocellulose membrane (0.45 µm; Amersham, Buckinghamshire, UK) or onto a polyvinyl difluoride (PVDF) hydrophobic membrane (ProBlott, Applied Biosystem, Foster City, Calif) by using a trans-blot cell from BIO-RAD at 0.45 A and 100 V for 4 hours at 4°C. The unoccupied protein-binding sites were blocked by incubation with PBS (pH 7.4) with 0.5% (v/v) Tween-20. The nitrocellulose membrane was then cut into strips, which were incubated overnight with each patient’s serum and a negative serum as a control. IgE binding was detected by incubation with iodine 125–labeled anti-human IgE diluted 1:4 (v/v) in blocking solution and exposed on autoradiographic film (Hyperfilm, Amersham) in exposure cassettes at –70°C for 4 days.

Figueredo et al. (1999) [796] transfered proteins electrophoretically to nitrocellulose membrane (BioRad, Richmond, CA, USA) in 0.025 mM Tris (pH 8.3), 0.192 mM glycine, 0.005% SDS and 20% methanol at 70 mA for 120 min. After transfer, the membrane was saturated for 60 min with 10 mM Tris buffered saline (TBS) containing 3% (w/v) bovine serum albumin (BSA). The membranes were then incubated with the patient's serum diluted 1:5 in 10 mM TBS containing 3% BSA and 1% (v/v) Tween 20 for 12-14 h. After four washes with 0.1% (v/v) Tween 20 in PBS, the membranes were incubated with antihuman IgE conjugated with peroxidase (The Binding Site, Birmingham, UK) for 3 h. The protein bands were developed by chemiluminiscence.

Pastorello et al. (2000) [465] found that IgE from 19 (86%) of 22 sera analysed reacted with a 9-kDa band, 8 (36%) recognized a 16-kDa protein, and 5 (22.7%) reacted with higher MW bands, 25-85 kDa. The 9 and 16 kDa proteins were identified from the N-terminal sequences as a nsLTP and an alpha-amylase inhibitor respectively.

Pasini et al. (2002) [760] report that immunoblotting experiments using sera of DBPCFC positive patients showed that the IgE-binding pattern of the proteins extracted by salt from the cooked sample was different from that obtained with the raw one, indicating that some physicochemical modifications of the allergens occurred during cooking of the corn flour. No IgE-binding was observed in the cooked sample corresponding to the 9 kDa protein band. However, IgE-binding to the band corresponding to the 50 kDa allergen was maintained in the cooked sample, showing that the physicochemical features and the IgE-binding ability of this protein were not affected by the heat treatment.

Figueredo et al. (1999) [796] report a strong IgE binding band at 16-18 kDa and several above 30 kDa. The binding to higher molecular mass proteins but not to the 16-18 kDa band could be inhibited by malt extract.

Polenta was made by boiling 25 g. fine milled corn flour for 30 minutes. 25 g. potato, 10g. carrot and turmezic and olive oil was cooked, mashed with a blender, added to polenta and mixed. The placebo used tapioca flour (Pasini et al. 2002 [760]).

A treadmill exercise challenge was done 40 minutes after ingestion of 30 g. El Moleno brand taco chips (Pauls & Cross 1998 [472]).

Up to 10 g. of the challenge substance was administered in graduated doses in a juice or “safe” food vehicle during a 90-minute period (Jones et al. 1995 [832]).

DBPCFC (Pasini et al. 2002) [760].

Open (Pauls & Cross, 1998) [472].

DBPCFC with negative checked by open challenge (Jones et al. 1995 [832]).

Pasini et al. (2002) [760] tested 16 patients.

Pauls & Cross (1998) [472] tested a 15 year old girl by open challenge with exercise.

Jones et al. (1995) [832] tested 17 SPT positive patients.

Pasini et al. (2002) [760] reported that 6/16 patients reacted to the challenge.

Pauls & Cross (1998) [472] report that at maximal exercise, the patient had diffuse pruritis, light-headedness, and a sense of fullness in her nasal passages. She then progressed to mild left facial and periorbital swelling.

Jones et al. (1995) [832] reported that 5/17 SPT positive patients reacted to the challenge.