A preseason booster prolongs the increase of allergen specific IgG4 levels, after basic allergen intralymphatic immunotherapy, against grass pollen seasonal allergy

BACKGROUND: Allergen specific IgG4 levels have been monitored as a surrogate marker for the tolerance inducing effect of subcutaneous immunotherapy (SCIT) in many studies. Its accuracy at group level has been well established, but IgG4 has not yet found its place in the daily care of immunotherapy patients. METHODS: Intralymphatic immunotherapy (ILIT) is a novel route for allergy vaccination against pollen allergy, where an ultrasound-guided injection of 1000 SQ-U Alutard is given directly into a groin lymph node. The suggested standard dosing so far has been one injection with 4 weeks in-between. In total 3000 SQ-U with the treatment completed in 2 months. IgG4 was measured with Immulite technique and rhinoconjunctivitis symptoms were estimated with daily online questionnaires. Mann–Whitney U-test and Wilcoxon Signed Rank test were applied for comparisons between groups and within groups, respectively. RESULTS: The present study demonstrates that a single, preseason ILIT booster of 1000 SQ-U Alutard 5-grasses(®), re-increases the allergen specific timothy-IgG4 levels, in patients already treated with ILIT before the previous pollen season. It also shows the feasibility of the ILIT-route for allergy vaccination of rhinitis patients, with or without concomitant asthma, with low degree of side effects and reconfirms high and sustained patient satisfaction. CONCLUSIONS: It is tempting to suggest that the allergen specific IgG4 levels can be used to build an intuitive algorithm for future clinical guidance of ILIT patients. Trial registration Is Intralymphatic Allergen Immunotherapy Effective and Safe?, ClinicalTrials.gov Identifier NCT04210193. Registered 24 December 2019—Retrospectively registered, https://clinicaltrials.gov/ct2/show/study/NCT04210193?term=NCT04210193&draw=2&rank=1