D2.277 - Allergy to CHIA and Reactivity with SESAME

We here present, a case of a 7-year-old child with a history of anaphylaxis due to cashew allergy. Subsequently, he suffered anaphylaxis with chia, with tested tolerance to sesame. Previous laboratory tests for sIgE (kU/L): Peanut 0.19 kU/L; Pistachio 2.19 kU/L; Cashew 1.76 kU/L. Total IgE 264 kU/L. Skin prick test (mm): Walnut (6x6); Chia (7x6).

Protein profiles were analyzed by SDS–PAGE using standard procedures. Samples were separated on 15% acrylamide/bisacrylamide gels and transferred onto PVDF membranes, with 1 µg of protein loaded per lane. For immunodetection, membranes were incubated with human serum diluted 1:5 in PBS–Tween (0.5%) containing 3% non-fat dry milk. A horseradish peroxidase–conjugated mouse anti-human IgE Fc antibody was used as the secondary antibody, and detection was performed using an enhanced chemiluminescence (ECL) substrate.

For inhibition assays, human serum (1:5 dilution) was pre-incubated with sesame extract prior to membrane hybridization.

In chia extract, the patient’s serum recognized proteins compatible with 2S albumin (10 kDa), previously unreported in the literature, 11S globulin (31 kDa), and a 29 kDa lectin. In pistachio extract, the serum recognized a protein compatible with manganese superoxide dismutase (25.7 kDa).

Inhibition assays sensitization to chia, with IgE binding predominantly to 2S albumins, 11S globulin, and lectin. Sensitization to sesame extract was observed with weak binding to sesame proteins in the 20-75 kDa range. Pre-incubation of the patient's serum with sesame reduced IgE binding to the 30 kDa and 50 kDa chia proteins. However, it was not able to inhibit IgE binding to the 10 kDa 2S albumin.

The patient with chia allergy primarily shoed IgE sensitization to three proteins: 2S albumin, 11S globulin, and lectin. Inhibition assay with sesame extract indicate that chia and sesame share at least two proteins (30 and 50 kDa). However, it was unable to inhibit IgE binding to the 10 kDa protein (2S albumin) of chia, which could explain the different clinical behavior against chia and sesame.