A five-year open follow up of a randomized, double-blind placebo-controlled trial of intralymphatic immunotherapy for birch and grass reveals remaining beneficial effects

Abstract

Background: Intralymphatic immunotherapy (ILIT) has been proposed as a novel, less time-consuming alternative to conventional allergy immunotherapy (AIT). Few previous studies have evaluated its long-term effects. The objective of the study was to complete a 5-year follow-up of a previously performed randomized, double-blind placebo-controlled trial of ILIT for a combination of birch and grass allergens. Methods: Fifty-eight patients with allergic rhinitis were treated with either placebo or a combination of ALK Alutard Birch and Grass 1000 SQ-U, three intralymphatic injections with one-month intervals. A year after the vaccination, symptoms induced by nasal provocation were significantly reduced. 5-6 years later, 20 out of 26 actively treated patients were followed up with a nasal provocation test (NPT), seasonal registration of the combined symptoms and medications score (CSMS), IgE and IgG4 levels in the blood and immunological markers in blood and lymph nodes and compared with 13 unvaccinated controls Results: The ILIT induced reduction in the NPT response seen in year one could not be convincingly reproduced in year five. The new CSMS scores were markedly lower among the previously treated patients than for the control group. Further, grass-specific IgG4 was increased, grass-specific IgE decreased, FcεR1 on basophils reduced, and the amount of memory T-cells in the lymph nodes increased. Conclusion: The combination of seasonal derived clinical data and immunological parameters supports the notion of a long-lasting effect of ILIT. These data support the concept of ILIT as a good alternative to traditional AIT in pollen-induced allergic rhinitis.