Rush allergen subcutaneous immunotherapy administered with infusion pump

Increasing time interval and decreasing allergen dose interval improves ex vivo desensitization of human blood basophils

BACKGROUND

Desensitization is a method for inducing temporary tolerance to allergen. The mechanism underlying desensitization is yet to be established.

METHODS

Basophil granulocytes in whole blood from grass pollen allergic subjects were desensitized ex vivo by sequential addition of increasing allergen concentrations. At each step basophil activation (CD193 ⁺ CD63⁺ ) was monitored with and without (background activation) allergen challenge at optimal concentration. The sequential desensitization protocol was compared to two single-dose desensitization protocols with threshold and subthreshold allergen concentrations. Incubation intervals and allergen concentrations were varied in order to optimise the protocol.

RESULTS

Sequential desensitization effectively reduced basophil response. The single-dose subthreshold protocol and single-dose threshold protocol did not reduce basophil activation with optimal allergen challenge from a mean 57.1 (95% CI: 32.7 - 81.5) to 50.4% (95% CI: 16.3 - 84.4; n = 5; P = 0.43) and 45.0% (95% CI: 23.1 - 66.9; P = 0.14) respectively, while the sequential desensitization protocol reduced activation to a mean 37.2% (95% CI: 16.3 - 58.1; P = 0.018). Reducing incubation time from 10 to 5 minutes increased mean background activation from 22.4 (95% CI: 11.7 - 33.1) to 30.0% (95% CI: 19.7 - 40.3; n = 5; P = 0.026). Increasing time intervals from 10 to 20 minutes reduced background activation from 30.9 (95% CI: 22.8 - 39.0) to 21.9% (95% CI: 16.0 - 27.7; n = 5; P = 0.020). Increasing allergen concentration intervals from 2-fold to 5- and 10-fold did not have significant effect on basophil activation.

CONCLUSIONS

Sequential desensitization ex vivo effectively attenuates the basophil response to allergen. Increasing the time spent at each step improves desensitization. This protocol could be valuable for investigation the mechanism of desensitization. © 2016 International Clinical Cytometry Society.

Accelerated immunotherapy schedules

Rush and cluster immunotherapy schedules are accelerated immunotherapy build-up schedules. A cluster immunotherapy schedule involves the patient receiving several allergen injections (generally 2-4) sequentially in a single day of treatment on nonconsecutive days. The maintenance dose is generally reached in 4-8 weeks. In rush immunotherapy protocols, higher doses are administered at 15- to 60-min intervals over a 1- to 3-day period until the maintenance dose is achieved. This review will serve as an update for accelerated immunotherapy schedules. The review will include recent investigations demonstrating the safety of cluster schedules in atopic dermatitis, pediatric patients, and inhalant allergen mixtures and an accelerated protocol utilizing an infusion pump for allergen delivery. There has also been further elucidation on the immunological changes which occur during accelerated immunotherapy. Finally, new studies analyzing systemic reaction risk factors are discussed.