Pistachio nut hypersensitivity: identification of pistachio nut allergens.

Type I hypersensitivity to pistachio nut antigens was demonstrated in three patients by means of immediate skin-test reactivity, specific IgE determination by a fluoroimmunoassay (CAP), CAP-inhibition and leucocyte histamine release. Sensitization to other dried fruits and pollens was observed in the patients. The CAP-inhibition studies revealed significant crossreactivity between pistachio and cashew nut belonging to the Anacardiaceae family, and between pistachio nut and other dried fruits belonging to taxonomically unrelated botanical families. No relevant crossallergenicity was observed between pistachio nut and Lolium and Olea pollens. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of a pistachio nut extract followed by immunoblotting analysis identified four IgE-binding bands with molecular weights of 34, 41, 52 and 60 kD.