Immunoglobulin E binding capacity to various types of Korean soy sauces among children sensitized to wheat and soybean.

Background: Soy sauce (SS) is made from soy or a mix of soybean and wheat proteins. With the rise in global consumption of Korean SS, understanding the allergenicity of its different types is essential.

Objective: This study is the first to evaluate whether the immunoglobulin E binding capacity (IgE+) in children sensitized to soybeans or wheat varies by SS types.

Methods: Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and an enzyme-linked immunosorbent assay (ELISA) using pooled and individual sera were performed with three SS types. Inhibition ELISA was performed using SS concentrate, extracts of wheat, and soybean.

Results: Guk-SS showed very faint protein bands, on SDS-PAGE. ELISA (pooled sera, n = 36) indicated that all groups had the lowest IgE+ to Guk-SS. In individual ELISA, patients sensitized to both wheat and soybeans (WS; n = 4) showed significantly higher IgE+ to all SS types (Yangjo > Jin > Guk) than those sensitized to wheat (W; n = 3) or Soy (S; n = 3) alone. The W group had IgE+ similar to the control group for Guk and Jin-SS, while the S group showed slightly higher IgE+ to Yangjo-SS. When soybean was used as an inhibitor, the IgE+ to Yangjo-SS and Jin-SS was inhibited by more than 50% (Yangjo > Jin). In contrast, wheat exhibited only subtle inhibition of both SS (< 20%). Converse showed similar results.

Conclusions: For pediatric patients sensitized to wheat, it is suggested that Korean SS be carefully introduced at home. For patients sensitized to soybeans, it is safest to try Guk-SS before attempting other types.