• birch pollen;
  • cross-reactivity;
  • fruits;
  • grass pollen;
  • potato;
  • RAST;
  • RAST inhibition;
  • SDS-PAGE/immunoblotting

Sera of patients suffering from birch pollinosis were studied in the radio-allergo-sorbent test (RAST) for the presence of IgE antibodies to various allergens of vegetable origin. The sera selected were positive in the RAST for both birch pollen and fruits. IgE antibodies directed against at least three different cross-reacting determinants in birch pollen were detected. In addition to periodate-susceptible cross-reacting determinants, which are found on a number of glycoproteins, two non-related periodate-resistent determinants were found in birch pollen, with molecular weights of 20 and 18 kD, respectively. The 20-kD component appears to be responsible for the co-occurrence of the binding of IgE to allergens of fresh fruits, whereas the 18-kD component appears to cause the cross-re activity among grass pollen, potato and fruits.