Long-Term Follow-Up of subcutaneous immunotherapy for allergic rhinitis

Abstract

Background: Subcutaneous immunotherapy (SCIT) is a disease-modifying treatment for allergic rhinitis whose central claim, that a finite course produces benefit persisting after injections stop, rests on a small number of controlled follow-up studies.

Objective: This review synthesizes evidence on long-term clinical outcomes after SCIT for allergic rhinitis, including symptom scores after discontinuation, secondary prevention of asthma, and the immunological correlates of durable tolerance.

Methods: We synthesized randomized controlled trials, prospective cohort follow-up studies, systematic reviews and mechanistic studies addressing subcutaneous immunotherapy, post-discontinuation efficacy, and immune tolerance in allergic rhinitis.

Findings: Discontinuation studies of three to four years of grass-pollen SCIT show benefit persisting for at least three years after stopping treatment [12], and children treated with mite or pollen SCIT show reduced new sensitizations and reduced asthma incidence at five to ten years [19,18]. Fifteen-year data indicate durability scales with treatment duration [21], while mechanistic studies link long-term tolerance to sustained IgG4 blocking-antibody activity and regulatory T-cell responses rather than to ongoing injections [28,27].

Conclusions: Long-term follow-up evidence supports SCIT as a disease-modifying intervention whose clinical and immunological benefits outlast a finite treatment course, though magnitude and duration of persistence vary with allergen and patient population.