## 3 Immunotherapy for Food Allergies  
Given the potential of exposure to a small amount of allergen to promote tolerance to that allergen and the successful use of immunotherapy for management of venom and pollen allergies, there has been increasing research into the use of immunotherapy to manage common food allergies [12]. Early use of subcutaneous immunotherapy for food allergy resulted in severe reactions, and so, recent focus has been on oral immunotherapy [37]. Forms of oral immunotherapy to treat food allergy include specific oral tolerance induction (SOTI) [12], where the allergen is ingested, or sublingual immunotherapy (SLIT), where a minute amount (picograms) of allergen, in the form of allergen extract or diluted allergen, is placed under the tongue [12, 38]. Both approaches start with a 'build up phase', initially starting with very small, diluted doses of the food protein with the amount of protein included in the dose slowly increased in a stepwise manner. This is followed by a \"maintenance phase\" with a consistent dose of allergen given at regular intervals. The regimes are followed with a \"discontinuation phase\" and a \"tolerance food challenge\" to test the effectiveness of the immunotherapy treatment. The entire process may take 12 months or longer to complete. Adverse events are common during oral immunotherapy--this risk of an adverse event increases with illness, exercise, menses and every time the dose of the food is increased [39, 40]. If regular consumption of the allergen is discontinued during the maintenance phase, there is a risk that tolerance will be broken, and an allergic reaction may follow exposure [38]. For food allergy, the endpoint of immunotherapy may not always be tolerance--the therapy may result in _desensitization_, an increase in the antigen dose required to elicit symptoms arising from a transient altered immune response and dependent on regular (daily) exposure to the allergen, or the therapy may result in true _tolerance_[41]--the ability to ingest the allergen without any symptoms once regular exposure has ceased, owing to persistent changes in the immune response. Desensitization still has a benefit in that larger doses of the allergen can be tolerated before eliciting a hypersensitivity reaction, thus lessening the potential for an anaphylactic reaction from accidental exposure. Oral immunotherapy has been attempted for many food proteins, but we have specifically chosen to discuss cow's milk and egg oral immunotherapy, because of the interest in using baked forms of these foods as a treatment strategy. There is one Cochrane review from 2012 [42] on oral immunotherapy for cow's milk allergy, but none for egg. The Cochrane review included 16 studies, representing five trials and concluded that milk oral immunotherapy can lead to desensitization in the majority of individuals, although development of long term-tolerance has not been established. Key trials reporting cow's milk oral immunotherapy and egg oral immunotherapy in the last 10 years are summarized in Tables 1 and 2. Nine studies reported outcomes of cow's milk oral immunotherapy and also nine for egg oral immunotherapy. These include three randomized controlled trials (RCTs) for cow's milk SOTI [38, 43, 44] and three RCTs investigating egg oral immunotherapy [45, 46, 47], but most of the studies report on open, uncontrolled prospective trials. We have added one trial [38] that was not included in the cows' milk immunotherapy Cochrane review. These studies have limitations. The studies utilized highly variable selection criteria, dosing regimens and maintenance doses, making them difficult to compare. The individual studies reported have limited statistical power, as only a small number of children were included in the treatment group. All of the 18 studies reported SOTI, and one study reported results of a SLIT/SOTI combination protocol for cow's milk immunotherapy. [PERSON] _et al_.