Duration of allergen immunotherapy in respiratory allergy: when is enough, enough?
OBJECTIVE
To investigate the duration of effective inhalant subcutaneous immunotherapy (SCIT) reported in the published literature and to determine if any specific biomarkers or clinical predictors exist that may identify patients who will remain in long-term remission after discontinuing treatment.


METHODS
Articles were selected from a search of the PubMed database from 1976 to 2006 using the search terms immunotherapy and allergen immunotherapy in combination with venom, allergic rhinitis, asthma, mechanism, efficacy, and duration, as well as articles known to the authors and referenced in review articles.


METHODS
Articles were selected if evaluation of efficacy of the primary allergic disease treated after discontinuation of SCIT was stated as one of the objectives of the study.


RESULTS
The rate of relapse after discontinuing SCIT ranges from 0% to 55% of patients in the studies reviewed in this article. The length of the specific allergen immunotherapy and allergen type (ie, perennial vs seasonal) may be variables that affect the duration of clinical remission after cessation of SCIT. One study found the duration of SCIT efficacy after discontinuation depended on duration of treatment and correlated with decrease in skin test reactivity.


CONCLUSIONS
Until specific tests or clinical markers are identified that will clearly distinguish between patients who will relapse from those who will remain in long-term clinical remission after discontinuing effective allergen immunotherapy, the decision to continue or stop immunotherapy must be individualized.
Cox
Linda
L
Allergy and Asthma Center, Ft Lauderdale, Florida 33334, USA. lindaswolfcox@msn.com
Cohn
John R
JR
D000818:Animals; D001249:Asthma / Q000628:therapy; D002415:Cats; D003888:Desensitization, Immunologic; D004285:Dogs; D006801:Humans; D006927:Hymenoptera / Q000276:immunology; D006967:Hypersensitivity / Q000628:therapy*; D007074:Immunoglobulin G / Q000097:blood; D011058:Pollen / Q000276:immunology; D039981:Pyroglyphidae / Q000276:immunology; D012220:Rhinitis / Q000628:therapy; D013997:Time Factors; D014688:Venoms / Q000276:immunology
D007074:Immunoglobulin G; D014688:Venoms