Time course of serum inhibitory activity for facilitated allergen-IgE binding during bee venom immunotherapy in children

• Published in: Clinical and experimental allergy 2009-09, Vol.39 (9), p.1353-1357
• Main Authors: Varga, E-M, Francis, J. N., Zach, M. S., Klunker, S., Aberer, W., Durham, S. R.
• Format: Article
• Language: English
• Subjects: Adolescent; Allergens - administration & dosage; Allergens - immunology; Animals; B-Lymphocytes - immunology; B-Lymphocytes - metabolism; bee venom immunotherapy; Bee Venoms - administration & dosage; Bee Venoms - immunology; Bees; Child; children; facilitated allergen-IgE binding (FAB); Female; Humans; Hypersensitivity - blood; Hypersensitivity - immunology; Hypersensitivity - therapy; Immunoglobulin E - blood; Immunoglobulin G - blood; Immunoglobulin G - immunology; Insect Bites and Stings - blood; Insect Bites and Stings - immunology; Male; serum inhibitory activity; time course; Time Factors
• ISSN: 0954-7894; 1365-2222
• DOI: 10.1111/j.1365-2222.2009.03303.x

Summary Background Immunotherapy for bee venom allergy is effective and provides long‐term protection. Venom‐specific IgG4 levels are increased but with no correlation with clinical improvement. Following grass pollen immunotherapy, elevation of antigen‐specific IgG4 is accompanied by increases in IgG‐dependent serum inhibitory activity for IgE‐facilitated binding of allergen–IgE complexes to B cells. As this ‘functional’ assay of inhibitory antibodies may be more predictive of clinical efficacy, we investigated the time course of serum inhibitory activity for IgE‐facilitated antigen binding during venom immunotherapy (VIT) in children and following 2 years of VIT withdrawal. Methods Ten bee venom‐allergic children (mean age: 9.3 years; m/f, 7/3) with moderate to severe allergic reactions to bee stings received VIT. A separate group of seven children (mean age: 14 years; m/f, 5/2) were investigated 2 years after VIT withdrawal. Ten age‐ and gender‐matched children served as non‐allergic controls. Allergen‐specific serum IgG4 and IgE levels were measured by ELISA at baseline, after 2 years of VIT and 2 years after VIT withdrawal. Serum inhibitory activity was assessed using the facilitated‐allergen binding (FAB) assay. Results Sera obtained during VIT significantly inhibited allergen–IgE binding to B‐cells (pre‐treatment=104±23%; 2 years=46±15%; P