A new reliable method for detecting specific IgE antibodies in the patients with immediate type wheat allergy due to hydrolyzed wheat protein: correlation of its titer and clinical severity.
BACKGROUND
Immediate-type wheat allergy caused by a specific hydrolyzed wheat protein (HWP-IWA), Glupearl 19S (GP19S), typically develops food-dependent exercise-induced anaphylaxis (FDEIA), but is different from conventional FDEIA, or simple wheat allergy in many aspects. The skin prick test (SPT) is considered to be the most effective method for diagnosis of HWP-IWA. As SPT is a relatively qualitative method, we developed quantitative and high-throughput test method for HWP-IWA.


METHODS
An enzyme-linked immunosorbent assay (ELISA)-based GP19S-specific IgE assay was tested using sera from 14 HWP-IWA and five conventional wheat-dependent exercise-induced anaphylaxis (CO-WDEIA) patients, as well as five healthy subjects. Then a validation study at five different institutions was carried out using sera from 10 HWP-IWA and five CO-WDEIA patients, as well as five healthy subjects different from the previous studies.


RESULTS
The mean unit values converted from measured absorbance of ELISA were 68.3, 1.3 and 1.1 respectively. Furthermore, the validation study revealed reproducible results across all five institutions, with the standard deviation (SD) being 0.3-0.4 for the healthy group, 0.2-0.6 for the CO-WDEIA group, and 3.8-9.6 for HWP-IWA group except for one case. One case of HWP-IWA was excluded from analysis due to the high SD of 53.3 units, indicating that samples with a unit value > 100.0 will affect inter-laboratory reproducibility.


CONCLUSIONS
Our findings suggest that the ELISA-based GP19S-specific IgE assay can be used to test HWP-IWA using venous blood samples, except for those with a unit value > 100.0.
Department of Dermatology, Fujita Health University School of Medicine, Aichi, Japan; General Research and Development Institute, Hoyu Co., Ltd., Aichi, Japan.
Masashi
M
Nakamura
Department of Dermatology, Fujita Health University School of Medicine, Aichi, Japan.
Akiko
A
Yagami
General Research and Development Institute, Hoyu Co., Ltd., Aichi, Japan.
Kazuhiro
K
Hara
Department of Dermatology, Fujita Health University School of Medicine, Aichi, Japan.
Akiyo
A
Sano
Department of Dermatology, Fujita Health University School of Medicine, Aichi, Japan.
Tsukane
T
Kobayashi
Department of Environmental-Immunodermatology, Yokohama City University Graduate School of Medicine, Kanagawa, Japan.
Michiko
M
Aihara
Department of Dermatology, Institute of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan.
Michihiro
M
Hide
Department of Dermatology, Shimane University Faculty of Medicine, Shimane, Japan.
Yuko
Y
Chinuki
Department of Dermatology, Shimane University Faculty of Medicine, Shimane, Japan.
Eishin
E
Morita
National Institute of Health Sciences, Tokyo, Japan.
Reiko
R
Teshima
Department of Dermatology, Fujita Health University School of Medicine, Aichi, Japan.
Kayoko
K
Matsunaga
D000293:Adolescent; D000328:Adult; D000485:Allergens / Q000276:immunology*; D000918:Antibody Specificity / Q000276:immunology*; D052179:Antigens, Plant / Q000276:immunology*; D016022:Case-Control Studies; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D005903:Gliadin / Q000276:immunology; D005983:Glutens / Q000276:immunology; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D012882:Skin Tests; D014908:Triticum / Q000009:adverse effects*; D021182:Wheat Hypersensitivity / Q000175:diagnosis* / Q000276:immunology*; D055815:Young Adult
D000485:Allergens; D052179:Antigens, Plant; D007073:Immunoglobulin E; D005983:Glutens; D005903:Gliadin