Prick Test and Immunoallergic Profile to Soy Allergens in Cuban Population

Introduction: Food allergy is increasing worldwide. Soy is widely used as a hidden ingredient in many food products. Sensitization to Soy allergens can be important in Cuba, although the exact sensitization prevalence is not well known.

Objective: To perform a preliminary assessment of allergic sensitization and IgE specificity profile to Soy allergens in Cuban allergic patients.

Methods: The Skin Prick Test was performed using a glycerinated allergenic extract of soy beans (BIOCEN, Cuba) at 5 mg/mL protein content. Two groups were studied: a cohort of general adult population (N=303), and patients suspected of food allergy, attending allergy services at 4 hospitals in Havana, comprising 159 adults (above 16 years old) and 157 children (2-16 years). A group of 40 bakers exposed to soy flour was also studied. The IgE and IgG4 binding profile of 32 selected SPT-positive patients, was further analyzed by Western Blotting.

Results: In the general adult cohort the prevalence of sensitization was 4.3%. Whereas, among patients suspecting food allergy the positivity rate was much higher: 68.2% for adults and 34.4% for children. The most frequent clinical manifestation among positive patients was Urticaria or Dermatitis (69%) for adults and for children respiratory symptoms were also common (74%). 24.4% of bakers were SPT-positive, showing mostly respiratory symptoms. IgE binding was mostly shown by a 30KDa band in bakers (possibly Gly m Bd30K, a cysteine-protease). The IgG₄binding profile was similar to IgE.

Conclusions:  Allergic sensitization to soy as food can be important in Cuba, with prevalence values similar to other countries. Therefore, it should be taken into account for improving the specific diagnosis of allergy.