Study population eligibility criteria
In all, 126 patients were assessed for eligibility. Forty-four did not meet the inclusion criteria, 7 withdrew consent before treatment and 1 was excluded for unknown reasons (Fig. 1). Fifty-seven patients with allergic rhinoconjunctivitis due to birch and timothy pollen allergens were randomized in 2014 and 17 patients 2015. The 74 patients, including 35 females, were 19–53 years old and had seasonal allergic symptoms to birch and grass (Table 1). Their skin prick test was >3 mm and displayed IgE to birch and timothy >0.35 kU/L. Exclusion criteria were pulmonary disease, < 80 % of predicted forced expiratory volume at the end of the first second (FEV1), use of more than 800 µg inhaled budesonide (or equivalent) per day, pregnancy, severe arterial hypertension, autoimmunity, cardiovascular, hepatic, renal, upper airway or metabolic disease, mental incapacity, alcohol abuse, medication interfering with immune response or beta-blockers. From earlier studies we expected 8 out of 9 patients would improve at least 40%. With 40 active treated and 20 in the placebo group, with an alpha of 0.05 the power was calculated to 92%.