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antigen desensitization; allergen immunotherapy

Principle: 1) prevents anaphylaxis by favoring formation of univalent haptens 2) univalent haptens can bind IgE on surface of mast cells but do NOT cause cross-linking & degranulation 3) similar in principle to homeotherapy Indications: 1) symptoms that occur after natural exposure to the allergen 2) demonstrable IgE antibodies against the antigen 3) antigen is not easily avoided 4) trial of medical therapy has failed 5) anaphylactic reaction to hymenoptera venom Contraindications: - avoid on days where patient has symptoms of asthma - use of beta-blockers relatively contraindicated - beta-blocker reduce effectiveness of epinephrine in treatment of anaphylaxis [4] Procedure: 1) subcutaneous & oral protocols 2) subcutaneous protocols should be performed by experienced personelle in an intensive care unit (ICU) setting - monitor for at least 30 minutes after injection [4] 3) sublingual protocol FDA-approved for grass pollen [5,6] 4) avoid premedication with antihistamines & glucocorticoids 5) drug desensitization for sulfonamides may be performed on an outpatient basis a) not IgE mediated b) induction of T-cell tolerance c) multiweek regimen Clinical significance: Effects of immunotherapy on allergic reactions: 1) production of IgG antibodies against allergen 2) reduction in IgE response after allergen exposure 3) increased allergen-specific IgG & IgA in respiratory secretions 4) reduced release of mediators by allergen-challenged basophils (derived from peripheral blood) 5) changes in cytokine production by T-helper lymphocytes 6) induction of anergy in allergen-responsive T-helper lymphocytes a) certain fragments of allergens down-regulated T-helper activity but do not stimulate release of mediators by mast cells b) may evenually form new approach to allergen immunotherapy Adverse effects: - anaphylaxis - rare, but be prepared [4] Notes: Specific agents: - NSAIDs 1) desensitization to aspirin produces cross-desensitization to all NSAIDs 2) sensitization persists for 2-7 days after each dose 3) interruption of NSAIDs for > 48 hours requires repeat desensitization - pollens, grass [2,3]

Related

protocol for oral desensitization to beta lactam antibiotics

Specific

sublingual immunotherapy (SLIT)

General

clinical procedure

References

  1. Medical Knowledge Self Assessment Program (MKSAP) 11, American College of Physicians, Philadelphia 1998
  2. Lin SY et al Sublingual Immunotherapy for the Treatment of Allergic Rhinoconjunctivitis and Asthma. A Systematic Review. JAMA. 2013;309(12):1278-1288. PMID: 23532243 http://jama.jamanetwork.com/article.aspx?articleid=1672214 - Nelson HS Is Sublingual Immunotherapy Ready for Use in the United States? JAMA. 2013;309(12):1297-1298. PMID: 23532248 http://jama.jamanetwork.com/article.aspx?articleid=1672220
  3. Didier A et al. Sustained 3-year efficacy of pre- and coseasonal 5-grass- sublingual immunotherapy tablets in patients with grass pollen-induced rhinoconjunctivitis. J Allergy Clin Immunol 2011 Sep; 128:559. PMID: 21802126
  4. Epstein TG et al. AAAAI/ACAAI surveillance study of subcutaneous immunotherapy, years 2008-2012: An update on fatal and nonfatal systemic allergic reactions. J Allergy Clin Immunol Pract 2014 Mar/Apr; 2:161 PMID: 24607043
  5. Creticos PS et al. Randomized, double-blind, placebo-controlled trial of standardized ragweed sublingual-liquid immunotherapy for allergic rhinoconjunctivitis. J Allergy Clin Immunol 2014 Mar; 133:751 PMID: 24332263 http://www.jacionline.org/article/S0091-6749%2813%2901702-8/abstract
  6. FDA News Release: April 2, 2014 FDA approves first sublingual allergen extract for the treatment of certain grass pollen allergies. http://www.fda.gov/NewsEvents/Newsroom/PressAnnouncements/ucm391458.htm