High Threshold Peanut Challenge Study

Completed

Brief Summary: This protocol is designed to better characterize a sub-population of peanut sensitized individuals who may be non-allergic, despite significant sensitization, or who may be allergic, but at high threshold doses. By specifically targeting participants who met the initial screening criteria of the active adult PN OIT study, Protocol 2012p002153 / AADCRC MGH-004 (MGH-004), but failed to react during the pre-treatment 443 mg challenge to peanut, the investigators anticipate that the investigators will identify individuals who have become spontaneously tolerant, despite persistent sensitization. The investigators might also find that clinical sensitivity persists but only with higher thresholds, or that sensitivity has increased (or is variable) since the previous allergen exposure. By repeating DBPCFCs through to a full serving dose (7.4 gram), the investigators will distinguish participants who react only at higher doses from those who were not truly peanut allergic, address whether their sensitivity has changed, and have the opportunity to further investigate their immune response to peanut allergen.

Detailed Description: The primary objective of the study is to identify and characterize a sub-population of high-threshold peanut allergic individuals and characterize their immunological phenotype in comparison with the low-threshold peanut allergic individuals enrolled in the adult PN OIT study (NCT01750879).

Clinical Objective:

To evaluate the clinical status of peanut-sensitized individuals previously passing a DBPCFC to 443 mg as being either: non-allergic, stably high-threshold allergic or more clinically reactive on repeat exposure.

Recruitment & Eligibility

Inclusion Criteria

Failure to react to 443 mg of peanut protein during the DBPCFC1 visit of protocol 2012p002153 / AADCRC MGH-004.
Males and females of all ethnic/racial groups aged 7-55 years old who are otherwise healthy.
Willingness to sign consent (or for parent/guardian to sign consent).
Willingness to sign the assent form, if consent provided by parent/guardian.

Exclusion Criteria

History of severe anaphylaxis
Severe or Moderate asthma
Poorly controlled asthma
Diagnosis of other severe or complicating medical problems, including autoimmune or chronic immune inflammatory conditions or gastrointestinal inflammatory conditions
Inability to cooperate with and/or perform oral food challenge procedures
Primary Immune Deficiency
Current use of beta blockers, angiotensin converting enzyme inhibitors, or monoamine oxidase inhibitors
Women of childbearing potential who are pregnant, planning to become pregnant, or breastfeeding
Use within the past 6 months of other systemic immunomodulatory treatments
Clinical signs or symptoms of anemia
Hematocrit <0.36 for adult females or <0.38 for adult males
Hematocrit <0.34 for children 7-18 years of age
Weight <23 kg

Arm && Interventions

Group	Intervention	Description
Low dose challenge passed	Peanut flour	Individuals who tolerated without dose limiting symptoms the screening food challenge for a parent interventional trial
Low dose challenge passed	Toasted oat flour	Individuals who tolerated without dose limiting symptoms the screening food challenge for a parent interventional trial

Primary Outcome Measures

Name	Time	Method
Consistency of High Threshold Reactivity	4 weeks	The proportion of high-threshold peanut allergic individuals among participants who previously failed to react to a 443 mg peanut protein challenge in NCT01750879 who also reacted \>443 cumulative total dose on repeat challenge

Secondary Outcome Measures