Intralymphatic Immunotherapy improves grass pollen allergic rhinoconjunctivitis. A three-year randomized placebo-controlled trial

Abstract Background Allergic rhinoconjunctivitis is a global health problem. Different Allergen ImmunoTherapy (AIT) regimes are marketed but have low adherence because they are expensive, complex and time consuming. New AIT forms are needed. Objective In a three-year follow-up double-blinded randomized placebo-controlled trial we aimed to investigate effect of intralymphatic AIT (ILIT). Methods Patients with grass pollen rhinoconjunctivitis were treated with either three ILIT injections and an ILIT booster one year later, three ILIT injection and a placebo booster or three placebo injections and a placebo booster. Primary outcome was improvement in a combined symptom and medication score, cSMS. A novel evaluation tool with a linear regression model of cSMS and grass pollen counts was developed. Secondary outcomes were changes in grass specific immunoglobulins and skin and nasal provocation tests to grass pollen. Results 36 patients were included. Log10 transformed cSMS was reduced by 0.30 (95%CI 0.11 – 0.49), p=0.002 equalling 48.5% (95%CI 24.5% – 62%), in the entirethree-year follow-up period, significant only in the first follow-up season but not in the second and third season. The regression model showed a 37%, p Conclusion Intralymphatic immune therapy gives a substantial reduction in grass pollen allergy symptoms and use of rescue medication, significant in the first season after treatment. A booster injection had no additional effect.