Presented at:
British Society of Allergy and Clinical Immunology
Loughborough, UK, July 2006
Increased serum inhibitory activity for basophil histamine release corresponds with reductions in early skin responses in a time-course of grass pollen immunotherapy
Wilcock LK, Francis JN, Paraskevopolous G, Aalberse RC, Stapel SO, Till SJ and Durham SR
Upper Respiratory Medicine, Allergy and Clinical Immunology, National Heart and Lung Institute, Imperial College, London, UK; Sanquin CBL, Department of Allergy, Amsterdam, the Netherlands.
Immunotherapy has modest effects on IgE levels yet reductions in early skin responses are a feature of treatment and may reflect the induction of functional blocking antibodies.
18 patients were randomised to receive active grass pollen immunotherapy (n=12) or placebo injections (n=6) for one year. Early phase responses (EPR) to intradermal allergen challenge, serum allergen-specific IgE levels and serum-inhibition of basophil histamine release were measured at intervals throughout the study.
During the maintenance phase, skin EPR were significantly suppressed in the active group compared to placebo (p=0.01), significant increases in inhibitory activity for basophil histamine release were detected in the active group compared to placebo (p=0.002). No differences in allergen-specific IgE levels were detected between the groups. Reductions in EPR in the active group were significantly reduced from baseline at 8 weeks following the start of treatment (p=0.02), this corresponded with increases in serum inhibition of basophil histamine release detected at 8 weeks (p=0.03).
The induction during allergen immunotherapy of functional blocking antibodies capable of inhibiting IgE-mediated responses corresponds with suppression of skin EPR and may represent an important mechanism of successful treatment.