Late-onset anaphylaxis to fermented soybeans: the first confirmation of food-induced, late-onset anaphylaxis by provocation test.
BACKGROUND
Late-onset anaphylactic reactions without early-phase reactions are rarely reported. The hypothesized mechanism of late-onset anaphylaxis to fermented soybeans is delayed absorption or release into the bowel rather than an immunologic phenomenon.


OBJECTIVE
To investigate the mechanisms of late-onset anaphylaxis to fermented soybeans in 2 patients and to characterize the allergens involved in anaphylaxis caused by fermented soybeans.


METHODS
Two patients underwent skin prick-by-prick tests with fermented soybeans as is. We used an open challenge for the provocation test of anaphylaxis and measured changes in plasma histamine, plasma tryptase, serum eosinophil cationic protein, and plasma leukotriene B4 levels in 1 patient. In addition, specific IgE against fermented soybeans and the allergens of fermented soybeans were detected by enzyme-linked immunosorbent assay and immunoblotting, respectively.


RESULTS
The results of the prick-by-prick tests with fermented soybeans as is were positive in both patients and negative in control subjects. The challenge with 50 g of fermented soybeans caused generalized urticaria and dyspnea 13 hours after ingestion of fermented soybeans in 1 patient. In addition, his plasma histamine and tryptase levels transiently elevated during the anaphylactic event. In enzyme-linked immunosorbent assay, the patients showed elevated IgE levels to the proteins of fermented soybeans. Serum IgE antibodies of patients 1 and 2 were bound to approximately 5- and 26-kDa proteins in immunoblotting of fermented soybeans, respectively.


CONCLUSIONS
To our knowledge, this is the first report of late-onset anaphylaxis provoked by the challenge test half a day after ingestion of fermented soybeans.
Inomata
Naoko
N
Department of Dermatology, Yokohama City University School of Medicine, Yokohama, Japan. ninomata@med.yokohama-cu.ac.jp
Osuna
Hiroyuki
H
Yanagimachi
Masumi
M
Ikezawa
Zenro
Z
D000328:Adult; D000707:Anaphylaxis / Q000276:immunology*; D019937:Diagnostic Techniques and Procedures; D005512:Food Hypersensitivity / Q000175:diagnosis / Q000276:immunology*; D006801:Humans; D008297:Male; D012882:Skin Tests; D045730:Soy Foods / Q000009:adverse effects*; D013025:Glycine max / Q000009:adverse effects; D013997:Time Factors