Background: Cluster immunotherapy is becoming increasingly used. It allows for a rapid build up phase and the administration of higher doses of allergen in a shorter period of time.
Objectives: To evaluate the effect of short-term pre-seasonal immunotherapy using a glutaraldeyde-modified allergen vaccine in reducing specific nasal hyperreactivity in nasal challenge tests.
Materials and methods: Thirty-three patients were selected. All patients had a positive history of allergic rhinitis and skin tests to grass pollen, although most of them (72.7%) were sensitized to other allergens as well. The study was conducted outside of the pollen season and the patients did not receive any pharmacological treatment during this period of time. Two randomized groups of patients were established; Group A: 22 patients (13 females and nine males) and Group B, 11 control patients (seven females and four males). Patients in Group A received immunotherapy with a vaccine containing 50% of the wild grasses Trisetum paniceum and Dactylis glomerata. All patients underwent titrated nasal provocation tests (NPT) before and after completion of the study (2.3 and 2.8 months for Groups A and B, respectively). The administration schedule consisted of 0.1 and 0.2 mL at day 1, followed by 0.3 and 0.5 mL at day 7, 0.5 mL after 2 weeks followed by 0.5 mL monthly. A single vial was used containing an allergen concentration of 10 000 TU/mL (105 microg of total protein and 24.6 microg of Group 1 plus 5 allergens/mL). A mean of 6.5 injections were administered to Group A patients between NPTs.
Results: There were no significant differences between both groups at the beginning of the study (P=0.48). At the end, only Group A patients needed significant greater threshold concentrations for a positive NPT than at the beginning (P=0.002).
Conclusions: A short-term cluster pre-seasonal inmunotherapy with a modified vaccine containing a mixture of grass pollen is effective as determined by an objective measure after only a mean 2.3 months of treatment.