Conjunctival allergen provocation tests, IgE, IgG4 and skin prick tests
CAPT with timothy were performed before ILIT and the first year post ILIT, and showed a higher tolerance threshold in patients receiving ILIT with birch and 5-grass (p<0.05) and 5-grass and placebo (p<0.05), but not significant in patients who received ILIT with birch and placebo (p=0.19, see Table S1 in the Supplementary information). The IgE levels to birch decreased from baseline to three years post ILIT from 25.45 to 17.71 kU/L (p<0.01 in the group treated with birch and placebo; in the group treated with 5-grass and placebo levels went from 33.18 to 24.42 (p<0.01). The levels of IgE to timothy decreased after ILIT with birch and placebo from 16.60 to 11.00 kU/L (p<0.05); similar, but non-significant, differences were determined after ILIT with 5-grass and placebo. IgE levels to both birch and timothy decreased slightly after ILIT with both birch and 5-grass (see Table S1 in the Supplementary information). Levels of IgG4 antibodies to birch and timothy remained unchanged in all three treatment groups, except for IgG4 levels to timothy, which increased from in mean 0.36 to 0.44 mg/L (p<0.05) after ILIT with birch and 5-grass (see Table S1 in the Supplementary information). Skin prick test for reactivity to birch and timothy allergens remained unchanged during the study period (see Table S1 in the Supplementary information).