Marcucci F, Sensi L, Carrarelli C, et al. Allergy. 2002;57:23–28
Purpose of the Study.
To assess the safety and clinical efficacy of low-dose nasal immunotherapy (LNIT) in children with dust mite allergy.
Thirty-two symptomatic children between the ages of 4 and 14 years with perennial allergic rhinitis to dust mites.
This was a multicenter, randomized, double-blind, placebo-controlled study conducted over a 2-year period. After baseline evaluation and 1-month washout period, participants were randomized to the placebo or modified LNIT group. Participants in the active group received increasing nasal doses of dust mite allergen to a maintenance dose of 80 allergen units (AU). The maintenance dose was given at home on a weekly basis for 18 months. Clinical symptoms, medication scores, threshold dose with specific nasal provocation test (NPT) (dose required to elicit 2 of 4 nasal symptoms including itching, sneezing, rhinorhea, and obstruction), and serum immunoglobulins IgE and IgG4 were followed. Statistical analyses were done to compare symptom and medication scores during period 1 (November 1994-March 1995) and period 2 (November 1995-March 1996). Results of NPTs and immunologic assays were compared at baseline, 5 and 18 months.
Twenty-six participants completed the study (12 active and 14 placebo), and there were no serious local or systemic reactions. At baseline, the groups were similar in age, sex, duration of rhinitis, and results of NPT. There was no significant difference between groups in symptom or medication scores during the first period, however, participants in the active treatment group had significantly lower mean nasal symptom scores and mean medication scores during the second period. The threshold dose of allergen at NPT was significantly increased in the active treatment group when baseline and 18-month NPT results were compared. Also, the increase in the NPT threshold dose was significantly higher in the active treatment group when compared with placebo at the end of therapy. There was no statistically significant difference observed in IgE or IgG4 immunoglobulin levels between groups throughout the trial.
LNIT may be a safe and effective alternative to traditional immunotherapy in children with mild allergic rhinitis attributable to dust mites.
Few studies have assessed the clinical efficacy of nasal immunotherapy in children, and previous adult studies have had limited success resulting from increased symptoms of rhinitis associated with high-dose nasal immunotherapy. The current study utilizes a low maintenance dose in children with perennial allergic rhinitis and suggests a clinically significant reduction in symptoms and medication use as well as a significant increase in allergen threshold dose. The participants in this study had very mild symptoms of rhinitis, and it is unclear if similar results would be found in patients with moderate to severe disease. Additionally, participants were told to follow their normal cleaning habits and dust mite exposure was not assessed in either group. Therefore, it is difficult to say whether the apparent improvement observed in the active treatment group was entirely attributable to the effect of LNIT rather than differences in exposure between groups or changes in the level of exposure during the study.