Immunoblot studies in allergic patients to hymenoptera venom before and during immunotherapy

Hymenoptera venom immunotherapy (VIT) is immunologically effective in patients with systemic allergic reactions after hymenoptera stings.

To evaluate the effect of VIT on specific IgE and IgG4 immunoblotting bands in VIT-treated patients.

Specific IgE and IgG4 immunoblotting bands for hymenoptera venom were performed with ALABLOT in sera of 17 patients (8 allergic to honeybee venom, 8 to wasp and 1 to polistes venom) before and during successful VIT (1 and 3 years). Before immunotherapy, all patients had experienced moderate/severe systemic reactions to a hymenoptera sting, with positive skin tests and venom-specific IgE. During immunotherapy all patients suffered field stings, without any systemic reaction.

Before VIT we detected several immunoglobulin-binding bands in different regions, with different individual patterns. After VIT, we observed in some patients (5/8 for honeybee venom, 6/8 for wasp and 1/1 for polistes) complete disappearance of some IgE-binding bands, mainly the 15 kDa region (honeybee) and 23 and 44 kDa regions (wasp and polistes). All patients showed decreased intensity of IgE-binding bands, most pronounced in regions 16, 44 and 52 kDa (honeybee); 44 and 35 kDa bands (wasp) and 23 kDa (polistes). Some patients showed de novo appearance of IgG4-binding bands (4/8 for honeybee and 8/8 for wasp venom), mainly in 52 kDa (honeybee) and in 23 and 44 kDa regions (wasp). All patients showed increased intensity of IgG4 bands that were already present before VIT, more pronounced in 52 and 44 kDa (honeybee) and in 44 and 35 kDa regions (wasp).

During successful VIT there are changes in intensity and number of IgE and IgG4 binding bands, which could reflect the immunological improvement induced by VIT. These changes are more pronounced/frequent in wasp VIT, a fact that could explain the best results usually seen in these patients.