High Threshold Peanut Challenge Study
Condition: Peanut Allergy
MeSH terms: Peanut Hypersensitivity
Study type: Observational

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.
    

Intervention name(s): Peanut flour; Toasted oat flour
Intervention type(s): Drug; Other
Intervention description(s): A Double-blind, placebo-controlled food challenge will consist of two challenges performed on separate days. One challenge will consist of 7 doses of peanut given every 20 minutes in increasing amounts up to a total of 7 grams of whole peanut (4 grams of peanut protein) masked by inclusion in vehicle food. The other challenge will consist of placebo material given similarly.; A Double-blind, placebo-controlled food challenge will consist of two challenges performed on separate days. One challenge will consist of 7 doses of peanut given every 20 minutes in increasing amounts up to a total of 7 grams of whole peanut (4 grams of peanut protein) masked by inclusion in vehicle food. The other challenge will consist of placebo material given similarly.
Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        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.
      
Biospecimen description: 
      PBMC
    
Keywords: food allergy; peanut; food challenge