Cross-reactivity among edible nuts: double immunodiffusion, crossed immunoelectrophoresis, and human specific IgE serologic surveys

With few exceptions (notably limited peanut cross-reactivity with pistachio and walnut), peanut antigens did not serologically cross-react with tree nuts. Walnut, pecan, and hazelnut form a group of strongly cross-reactive tree nuts. Hazelnut, cashew, Brazil nut, pistachio, and almond form a group of moderately cross-reactive tree nuts. Cross-reactivities between these groups are less pronounced (notably limited cross-reactivity of walnut and pecan with Brazil nut). The strongest cross-reactivities among tree nuts follow botanical family associations: (1) walnut and pecan in the family Juglandaceae and (2) cashew and pistachio in the family Anacardiaceae.