Moving Forward In Health Disparities: Aqueous Intradermal Immunotherapy

Abstract

Mites (Dp/Df and Blomia tropicalis) are the major allergens in the tropics. Subcutaneous Immunotherapy (SCIT), hallmark of the allergy specialty, is an expensive effective tool for house dust mite allergic rhinitis (AR). Intradermal administration of low-dose mite allergens provides a cost-effective alternative for the impoverished majorities in tropical settings. Forty-three AR children (ages 4-18) attending an allergy clinic were offered intradermal immunotherapy. Only 25 with a Total Nasal Symptom Score (TNSS) >100 points were recruited and 17 completed one-year treatment. Injections consisted of a non-incremental volume of 0.05ml containing 50ng of Dp/Df major allergens and 120ng of Blomia tropicalis allergens. Shots were given following a 3-month schedule: once weekly for the first 3 months, later bi-weekly, then every 3 weeks and finally, monthly until a year’s completion. TNSS and fVAS were registered throughout the treatment year. IgG4 and IL10 serum levels along with QoL questionnaire, were evaluated before and after treatment. Qualitative scores TNSS, fVAS and QoL significantly improved (p<0.05): 8.58±0.86 vs 4.7±3.0 points, 6.0±1.5 vs 3.2±1.4 points, 35.0±11.4 vs 8.3±4.8 points, respectively. Quantitative results for IL-10, Dp/Df IgG4 and Blomia tropicalis IgG4 significantly increased (p<0.05): 3.61±4.2 vs 18.5±15.1 IU/ml, 2.07±1.8 vs 16.2±13.4 IU/ml, 0.11±0.11 vs 12.69±13 IU/ml, respectively. Cost per shot was estimated at less than USD 10 cents, making this approach a significant cost-saving strategy. Only mild local reactions were observed. Clinical improvement/laboratory responses were attained with this novel intradermal cost-effective technique. Health disparities concerning allergen immunotherapy might find, if reproduced, a step forward.