The purpose of this study is to attempt to understand how desensitization works in peanut allergic children who are undergoing oral immunotherapy (OIT) to peanut. We want to identify the early changes in the desensitization process the immune cells undergo to become desensitized to the peanut protein.

Peanut allergic children will undergo an oral food challenge (OFC) to 1 gm peanut protein in order to accomplish two objectives: (1)to confirm the diagnosis of peanut allergy, and (2) to measure the amount of peanut protein it takes to cause an allergic reaction. Each subject will then undergo a modified rush phase in which the subject receives 6 doses of peanut protein in one day. The build-up phase begins afterward in which the subject's dose of peanut protein is increased every 2 weeks for 36 weeks. After the final build-up dose, the subject consumes that dose for 2 weeks after which he or she returns to the food allergy center for the second food challenge. If the subject successfully consumes this food challenge without symptoms, the daily dosing of peanut protein will be stopped and the subject will then undergo a third food challenge. If the subject successfully consumes the peanut protein during that challenge, he or she will return for a fourth food challenge to peanut.

Inclusion Criteria:

• Age 4 to up to 12 years of age of any gender, race, or ethnicity.
• Minimum weight 16 kg at the time of enrollment.
• Physician diagnosis of peanut allergy OR convincing clinical history of an allergic reaction to peanut.
• Detectable serum peanut -specific IgE level (CAP-FEIA ≥ 0.35 kU/L) and a positive SPT (wheal ≥ 3mm on skin prick test to peanut extract compared to a negative control.)
• Allergic reaction to ≤ 1 gm peanut protein during a blinded oral challenge test conducted at screening (e.g., a double-blinded, placebo-controlled food challenge [DBPCFC]).
• Written informed consent from parent/guardian.
• Written assent from subject if applicable
• Consumption of oat-containing product within 90 days prior to enrollment

Exclusion Criteria:

• History of allergic reaction to peanut consistent with severe anaphylaxis (defined as hypotension/shock; or neurologic impairment).
• Chronic disease other than asthma, atopic dermatitis, rhinitis requiring therapy; e.g., heart disease or diabetes.
• Active eosinophilic gastrointestinal disease in the past 2 years
• Participation in any interventional study for the treatment of food allergy in the 6 months prior to visit -1
• Inhalant allergen immunotherapy that has not yet reached maintenance dosing.
• Asthma defined as moderate or severe persistent by National Asthma Education and Prevention Program Expert Panel Guidelines (e.g. asthma that requires more than fluticasone 440 mcg or its equivalent daily for adequate control).
• Inability to discontinue antihistamines for skin testing, OFC and the initial dose escalation.
• Use of omalizumab or other non-traditional forms of allergen immunotherapy (e.g., oral or sublingual) in the 12 months prior to visit -1.
• Any systemic therapy which in the judgment of the investigator could be immunomodulatory (e.g. rituximab) in the 12 months prior to visit -1, Systemic corticosteroid therapy of up to a total of three weeks is allowed.
• Use of investigational drug in 90 days prior to visit -1.
• Plan to use any investigational drug during the study period.
• The presence of any medical condition that the investigator deems incompatible with participation in the trial.
• Inability to speak English.

31 months