Immunoblot studies in birch pollen-allergic patients with and without fruit hypersensitivity: part II: antibody...

Patients allergic to birch pollen also exhibit more hypersensitivity reactions to fresh fruits and vegetables than do patients allergic to other pollens. Several investigations have indicated a possible partial immunological identity between birch pollen and fruits. To study this, 23 birch pollen-allergic patients 12 with (FH+) and 11 without (FH-) fruit hypersensitivity and 10 nonatopic controls were examined with self-prepared apple-peel, cherry, and peach extracts by immunoblotting. The self-prepared extracts were characterized by histamine release studies with 20 FH+ birch pollen-allergic patients. Specific IgE, IgG, IgG1, IgG4, IgA, and IgM binding patterns of the fruit extracts presented an individual distribution with at least 1-3 IgE bands at varying molecular weight locations. The FH+ group expressed intense IgE binding to the different extracts compared to the FH- group, and even the control group showed all immunoglobulin classes, though different frequencies and intensities compared to the allergic groups. It seemed that the specific IgE > IgG > IgM relation to a single antigen is important for distinguishing between symptomatic and asymptomatic persons. With this hypothesis we found most IgE with less IgG binding to apple-peel in the region of 22-28 kd and 43-56 kd, cherry: 15-25 kd and 72- > 90 kd and peach 35-41 kd and 66-76 kd, suggesting that these proteins might be important for cross-reactivity with birch pollen and developing fruit hypersensitivity.