SUCCESSFUL REPLACEMENT OF ALLERGEN-SPECIFIC IMMUNOTHERAPY BY ALLERGEN-MIXTURE THERAPY

Background: Some clinicians utilize allergen-specific immunotherapy (s pecific therapy), employing only the extracts of allergens that produc e positive skin tests. Others use allergen-mixture immunotherapy (mixt ure therapy), employing premixed extracts containing both skin reactiv e and non-reactive (irrelevant) allergens. Objective: The purpose of t his study was to compare the efficacy of these two approaches and to i dentify sensitization to irrelevant allergens included in mixture ther apy. Method: A total of 20 adults with allergic rhinitis/asthma who we re switched from successful specific therapy (average duration of 6.1 years) to mixture therapy (2.0 years) were evaluated with symptom-medi cation scores, skin test results, and local/systemic reactions at thre e time points: before specific therapy, before, and 2 years after mixt ure therapy. Results: Symptom-medication scores for all patients impro ved at the end of specific therapy and remained improved during mixtur e therapy (12.3 versus 12.0 with P = .75). The sums of positive skin t ests at three points were not different (7.8 versus 8.3 versus 9.8 wit h P > .4 at all points). Reaction rates did not differ either. Skin se nsitization to irrelevant allergens occurred in five patients during m ixture therapy. These patients, however, also experienced spontaneous conversions from negative to positive reactions to the allergens not i ncluded in the therapy, indicating that sensitization may be partly du e to a spontaneous increase in skin reactivity. Conclusion: These find ings suggest that allergen-mixture immunotherapy is as efficacious as allergen-specific therapy and may be associated with skin sensitizatio n in some patients. There was no evidence of increased adverse clinica l reaction.