Immunotherapy with keyhole lampet hemocyanin-conjugated decapeptide vaccine in cypress pollen allergy

Summary Background Cupressaceae pollen allergy is a world-wide pollinosis but immunotherapy has rarely been tested. Immunotherapy is usually allergen-specific but new forms may be targeted towards IgE. Objectives A randomized, double-blind, placebo-controlled trial was carried out to assess the efficacy of a vaccine made of keyhole lampet hemocyanin (KLH)-conjugated decapeptide from the Fce4 domain of the IgE in cypress pollinosis. Methods Sixty patients with cypress pollen allergy were studied. They were included on a suggestive clinical history, positive skin tests and nasal challenge to cypress pollen extract. Three intramuscular injections of the vaccine (250 µg) or placebo were administered monthly with a booster injection 5 to 8 weeks later. The primary end-point criterion was the threshold dose inducing a positive nasal challenge. The secondary end-point was the symptom-medication scores measured when cypress pollen grains were over 50 grains/m3. Results Nasal challenge before treatment was non-significantly different between the placebo and vaccine groups. After treatment there was no significant difference between the two groups. Pollen counts were over 50 grains/m3 for 8 weeks during the trial. There was no significant difference in total symptom scores between the placebo and vaccine groups. The vaccine was safe. Conclusions The KLH-conjugated decapeptide vaccine was not effective in cypress pollen allergy.