001232 - Short-term Clinical and Immunologic Outcomes of House Dust Mite Sublingual Immunotherapy

Allergen immunotherapy for house dust mite (HDM) allergic rhinitis is conventionally evaluated after 1–3 years of treatment, yet early identification of clinical benefit or non-response could inform personalized management. Short-term markers, including symptom scores and immunologic changes, may predict long-term success. The Sino-Nasal Outcome Test-22 (SNOT-22) is a patient-reported symptom score (MCID ≥8.9 points) originally for chronic rhinosinusitis but also used in allergic rhinitis. HDM-specific IgG4 antibodies are induced during immunotherapy and can block IgE-mediated reactions, so the IgG4/IgE ratio is a proposed biomarker of tolerance.

This retrospective cohort study included 41 patients with HDM-induced AR who completed 6 months of daily SLIT using HDM tablets. Patients were evaluated at baseline and 6 months. Clinical outcomes were assessed using the SNOT-22 questionnaire, and changes ≥8.9 points were considered to exceed the MCID threshold. Serum HDM-specific IgE and IgG4 (to D. pteronyssinus and D. farinae) were measured, and IgG4/IgE ratios were calculated. Paired t-tests or Wilcoxon signed-rank tests were used for within-subject comparisons. Correlation between immunologic changes and SNOT-22 improvement was analyzed using Pearson and Spearman coefficients. Subgroup analysis compared IgG4/IgE changes between MCID achievers and non-achievers.

Of the 41 patients, 83% (n = 34) achieved a clinically meaningful improvement in SNOT-22 (≥8.9-point reduction) at 6 months. The median SNOT-22 score decreased from 45 to 22 (p < 0.001). Der f-specific IgG4/IgE ratios significantly increased (median from 0.011 to 0.023; p < 0.001), while Der p-specific ratios showed no significant change. However, no correlation was found between the degree of IgG4/IgE ratio change and SNOT-22 improvement (Der p: r = –0.05, p = 0.76; Der f: r = 0.05, p = 0.75). Subgroup analysis revealed no significant difference in IgG4/IgE changes between patients achieving MCID and those who did not. Notably, lower baseline Der f IgG4/IgE ratios were modestly associated with greater SNOT-22 improvement (Pearson r = –0.39, p = 0.013).

: The majority of patients with HDM-induced AR undergoing 6 months of SLIT achieved symptom improvement exceeding the MCID for SNOT-22, indicating meaningful clinical benefit within this short timeframe. Although a significant increase in Der f-specific IgG4/IgE ratio was observed, this biomarker did not correlate with clinical response. Our findings suggest that while early immunologic modulation is evident by 6 months, IgG4/IgE ratio alone is not a reliable surrogate marker for short-term symptom improvement. Nevertheless, the 6-month evaluation serves as a practical checkpoint for assessing SLIT efficacy, identifying early responders, and guiding personalized management strategies.