Methods: Subjects were recruited from patients of Allergy Associates of La Crosse, a single specialty practice that has offered SLIT for 43 years. Subjects were diagnosed with allergic rhinoconjunctivitis based on history and positive skin test results. Each patient dose was tied to individual antigen skin test results at a strength corresponding to the highest dilution that produced near-negative results and established a safe tolerance threshold. Upward immunotherapy dose titrations were established against declining skin test reactivity for safe build-up and to avoid unnecessary local and systemic reactions. Allergens treated varied by patient, as offending allergen numbers ranged from six to 24 (mean 15.15). Round one enrollment occurred from July through December; round three visits occurred from January through November, thus crossing multiple pollen seasons and limiting seasonal bias. Symptom severity was evaluated using the disease-specific validated Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ). Subjects completed the RQLQ at first visit before treatment onset and subsequent follow-up visits at three- to six-month intervals.
Results: Paired RQLQ results revealed statistically significant (P < 0.05) improvement in six of seven domains evaluated after patients’ first follow up appointment (mean 4.1 months). Improvements were seen in activities, non-nose/eye symptoms, practical problems, nasal symptoms, eye symptoms, and emotional categories. The total RQLQ for the whole cohort declined significantly (P < 0.05) from 126.02 to 74.96 within the first four months of treatment. Although short of achieving statistical significance, participants adhering to TID for SLIT showed better score improvement than suboptimally compliant patients.
Conclusions: This study represented a preliminary attempt to investigate the effectiveness of multi-antigen SLIT administered TID in a complex patient base. Over a 1000-fold range of antigen dilutions has been reported to produce clinical improvement with SLIT, suggesting that a straight dose-effect does not exist. Other factors such as multiple daily administration and patient-specific dosing have now shown statistically significant sustained and continuous symptom reduction after the first follow-up appointment.