Enzyme potentiated desensitization
Enzyme potentiated desensitization, or EPD, is a treatment for allergies developed in the 1960s by Dr. Len McEwen in the United Kingdom. EPD uses much lower doses of antigens than conventional treatment, with the addition of an enzyme, beta glucuronidase. EPD is available in the United Kingdom and Canada for the treatment of hay fever, food allergy and intolerance and environmental allergies, and was available in the United States until 2001, when the Food and Drug Administration revoked approval for an investigative study which it had previously sanctioned which had allowed EPD to be imported into the USA.
EPD is now under development for the treatment of autoimmune disease by a United Kingdom company called Epidyme[1] which has been granted a United Kingdom patent. There are very encouraging results in an experimental model of rheumatoid arthritis and work on treatments for further autoimmune diseases is planned. Such autoimmune diseases include multiple sclerosis, type 1 diabetes and myasthenia gravis.
EPD treatment
The enzyme beta glucuronidase is used to potentiate the desensitizing effect of a small dose of allergen. The quantities of both are smaller than those occuring naturally in the body, but not so small that they can be regarded as homeopathic. Intradermal injections are used. The treatment takes 3-4 weeks to become effective and the interval between treatments is gradually lengthened. Hay fever can generally be treated with two shots of EPD outside the pollen season.
Mechanism for EPD
The treatment uses dilutions of allergen and enzyme to which T-regulatory lymphocytes are believed to respond by favouring desensitization, or down-regulation, rather than sensitization. Once activated these lymphocytes travel to lymph nodes and reproduce or stimulate similar T-lymphocytes.
Evidence for the Effectiveness of EPD
EPD is considered experimental by some doctors and allergists. However, there is significant evidence for the efficacy of EPD in the treatment of hay fever as a result of a number of placebo-controlled, double-blind trials. All but one of these trials showed a significant improvement in the symptoms with probabilities of 0.001 to 0.01 (a chance of one in a thousand to one in a hundred that the results of the trial would be seen by chance alone assuming EPD had no effect),[2] [3] [4] [5] [6] [7] [8] [9] while one trial showed no overall effect.[10]
Safety of EPD
While the efficacy of EPD is sometimes the subject of controversy among the medical community, the safety of EPD has been proven. In a study under the control of an Investigational Review Board and reported by the American EPD Society 5,400 patients received at least 3 doses of EPD with no severe reactions.[11] No serious complications have been observed in more than 300,000 doses given since 1966.
By contrast conventional (escalating dose) immunotherapy has been responsible for at least 29 deaths in the United Kingdom, and is now banned in the United Kingdom except in hospital under close observation.[12]
Restrictions on EPD
EPD has not been developed for treatment of contact dermatitis and allergy to drugs or insect stings.[13]
References
- ^ Epidyme website use of EPD to treat autoimmune diseases.
- ^ Brostoff J., Fell P. (1990). "A single dose desensitisation for summer hay fever". Eur. J. Clin Pharmacol. 38: 77–79.
- ^ Astarita C., Scala G., Spoviero S., Franseze A. (1996). "Effect of enzyme potentiated desensitisation in the treatment of pollenosis : A double-blind placebo-controlled trial". J. Invest. Allergol. Clin. lmmunol. 6 (4): 248–255.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Longo G., PoIi F., Bertoli G. (1992). "Clinical efficacy of a new hyposensitising treatment, EPD (Enzyme Potentiated Desensitisation) in the therapy of pollenosis". Riforma Med. (107): 171–176.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Angelini G., Curatoli G., D’Argento V., Vena G. A. Pollinosi (1993). "Una nuova metodica di immunoterapia. Med. J. Surg. Med": 253-256.
{{cite journal}}: Cite journal requires|journal=(help)CS1 maint: multiple names: authors list (link) - ^ Di Stanislao C.. Di Berardino L., Bianchi I., Bologna G. (1997). "A double-blind, placebo-controlled study of preventive immunotherapy with EPD in the treatment of seasonal allergic disease". Allergie et lmmunologie. 30 (2): 39-42.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Caramia G., Franceschini F., Cimarelli Z.A., Ciucchi M.S., Gagliardini R., Rufllni E. (1996). "The efficacy of EPD, a new immunotherapy, in the treatment of allergic diseases in children". Allergie et lmmunologie. 28 (9): 308-310.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Di Stanislao C., Angelini F.; et al. (2002). "Beta glucuronidase short-term immunotherapy prevents seasonal rhinoconjunctivitis in grass pollen allergic patients by modifying dendritic cell phenotype". Allergy. 57 (Suppl 73): 76–77.
{{cite journal}}: Explicit use of et al. in:|author=(help) - ^ Boscolo M. A., Brivio G. "E.P.D. preventive therapy (McEwen method) vs. placebo: a double-blind trial". Poster presentation. European Congress of Allergy & Clinical Immunology. Brussels, July 1999.
- ^ Radcliffe M. J., Lewith G. T., Turner R. G., Prescott P., Church M. K., Holgate S. T. (2003). "Enzyme potentiated desensitisation in treatment of seasonal allergic rhinitis: double blind randomised controlled study". British Medical Journal. (327 2 August.): 251–254.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ Shrader, W A (2001). "The American EPD Study: 1993–2000" (PDF). White Paper for United States Senators and Representatives. Enzyme Potentiated Desensitization (EPD). p. 14. Retrieved 2006-09-16.
{{cite web}}: Unknown parameter|coauthors=ignored (|author=suggested) (help); Unknown parameter|month=ignored (help) - ^ JA Douglass, FC Thien and RE O'Hehir (1997). "Immunotherapy in asthma". Thorax. (52): 22–29.
- ^ L.M. McEwen "Enzyme Potentiated Desensistization" (patient pink handbook) 1993