Assessment of sensitization to grape and wine allergens as possible causes of adverse reactions to wine: a pilot study

Symptoms

The most frequently reported symptoms after wine consumption of the 19 participants
with self-reported wine intolerance were in accordance with our former study 12] (rhinorrhea, itching etc., Fig. 1). The participants stated that adverse reactions could be observed immediately up
to 2 h after consumption of grape products.

Fig. 1. Frequency of intolerance symptoms after wine consumption (n?=?29). Symptoms after
white-, red-, or white and red wine consumption were examined

Allergy testing

Prick test was conducted with 26 participants. Seven persons showed a positive reaction
(wheal of at least 3 mm diameter) towards any grape product (Table 1). Two of these persons reacted only towards red or white grapes (No. 7, 24) and one
person to red grape juice (No. 15). The other three persons reacted to grapes and
wine (No. 2, 8, 16) and only one person only to wine (No. 4) (Table 1).

Total IgE was above range in 13 participants (9 intolerant, 4 controls). Four of these
also showed a positive reaction in prick test (No. 2, 7, 15, 16). Only one person
showed specific sensitization with ImmunoCAP (grape: CAP class 2). This participant
(No. 7) also suffered from severe allergy to pollen (grass: CAP class 6; birch: CAP
class 5), and reacted towards CCD (MUXF3: CAP class 3). A preincubation of serum taken
from the same person at a later time point with CCD-blocker led to a reduction of
the concentration of MUXF3-specific IgE (2.06 kU/l before, 0.25 kU/l after) as well
as of grape-specific IgE (0.5 kU/l before, 0.04 kU/l after) while birch-specific IgE
was not reduced after CCD blockade (91.2 kU/l before, 96.1 kU/l after).

In addition, CAST was performed with isolated leucocytes from 25 persons to analyze
basophil activation. Release of sulfidoleukotrienes by basophil granulocytes was measured
after stimulation with varying concentrations of purified LTP. Overall, basophil granulocytes
of five participants (No. 7, 13, 15, 19, 24) reacted with increased leukotriene release
(sulfidoleukotriene concentration??200 pg/ml). Thus, a relationship of CAST and prick
test could be found since three (2 intolerant No. 7, 15; one control No. 24) of these
five persons also showed a positive prick test.

For participant No. 7 all tests were positive (total IgE 910 kU/l, grape: CAP class
2, birch: CAP class 5, MUXF3. CAP class 3). This person also showed a strong reaction
towards different grape and wine proteins in the ImmunoBlot. Besides a severe reaction
of IgE Ab to grape and wine proteins a reaction to peach could be detected, while
a reaction to LTP was hardly detectable (Fig. 2). After incubation of the serum taken from the same person at a later time point
with CCD-blocker (purified MUXF structure of digested bromelain) the reactivity against
grape proteins completely disappeared, while a strong reactivity to a birch protein
of nearly 17 kDa (Bet v 1) could still be detected (Fig. 3), this is in accordance to the ImmunoCAP results. The serum of participant No. 23
showed a weak ImmunoBlot, but the history of this person showed no evidence for intolerances.
Sera from the other tested participants showed no reaction in ImmunoBlot experiments.

Fig. 2. ImmunoBlot of IgE antibody reactivity applying different grape and wine proteins.
a ImmunoBlot of participant No. 7, who showed positive reactions in all tests; b Coomassie-stained 15 % SDS-PAGE. Samples: 1: peach; 2: red grapes; 3: Dornfelder
grapes (winery Fleischer, Mainz); 4: white grapes; 5: Dornfelder wine (after PVP precipitation);
6: purified LTP from Dornfelder wine [15]; 7: purified LTP from Dornfelder grapes
[15]; 8: Riesling wine (after Lyophilisation); 9: RunBlue Dual Color SDS marker (Expedeon,
Cambridge,United Kingdom). For SDS-PAGE 30 ?l of the extract, which was treated 3:1
with SDS sample buffer and incubated 95 °C for 10 min, was applied

Fig. 3. ImmunoBlot of IgE antibody reactivity applying grape and birch extracts after inhibition
of the CCD specific IgE antibodies. a ImmunoBlot control of patient No. 7. b ImmunoBlot after preincubation of serum with 20 ?g/ml CCD-blocker. c Coomassie-stained 12.5 % SDS-PAGE. Samples: 1: white grapes; 2: birch; 3: Precision
Plus Protein dual Color Standard (BioRad, Munich, Germany)