Fuente: PubMed "pollen" World Allergy Organ J. 2026 Apr 8;19(4):101381. doi: 10.1016/j.waojou.2026.101381. eCollection 2026 Apr.ABSTRACTBACKGROUND: Allergen specific immunotherapy (AIT) is a guideline-approved treatment that can modify the course of allergic rhinitis (AR). The treatment regimen for AIT in pollen-induced AR is more complex due to the impact of pollen exposure and there is no uniform recommendation on the time to initiate AIT for pollen-induced AR.OBJECTIVE: The aim of this study was to investigate whether the initiation timing pre- or post-pollen season (PS) influence efficacy of Artemisia Annua sublingual immunotherapy (SLIT) in patients with allergic rhinitis.METHODS: This was an open-label multicenter clinical trial. We recruited eligible patients in March 2022 and November 2022 from 3 treatment centers, and initiated SLIT before and after the PS of Artemisia Annua in 2022. Meanwhile, a control group was also set up to receive rescue medicine. Symptoms and medication usage were assessed throughout the PS, efficacy of SLIT was evaluated by comparing changes from baseline in: 1) the combined symptom-medication score (CSMS), 2) total nasal symptom score (TNSS), 3) ocular symptom score (TOSS), and 4) medication score (MS). A linear mixed-effects model (LMM) was employed to analyze the effects of treatment (SLIT vs. control), treatment initiation timing (pre-vs. post-season) on therapeutic outcomes.RESULTS: SLIT significantly alleviated symptoms and reduced medication use compared to control, regardless of whether initiation before or after the PS. Furthermore, the LMM indicated that initiation timing (pre-vs. post-season) did not significantly affect treatment efficacy. There was no significant interaction effect between initiation timing and treatment group. It was also shown that higher pollen concentration was significantly associated with worse symptom severity and increased medication use.CONCLUSION: This multi-center study further confirms the efficacy of SLIT for Artemisia Annua-induced AR. We demonstrated that initiating SLIT before or after the PS did not affect its therapeutic efficacy by using LMM. This finding addresses a gap regarding the optimal timing for SLIT initiation and provides crucial evidence to inform clinical decision-making, offering greater flexibility in treatment scheduling.CLINICAL TRIAL REGISTRATIONS: NCT05318157; Registered March 22, 2008.PMID:42006631 | PMC:PMC13091189 | DOI:10.1016/j.waojou.2026.101381