Peanut epitopes for IgE and IgG4 in peanut-sensitized children in relation to severity of peanut allergy.
BACKGROUND
Better understanding of the relationship between antibody response to peanut and clinical sensitivity might lead to more accurate prognostication.


OBJECTIVE
We sought to investigate peanut-specific IgE and IgG4 epitope diversity in relation to challenge-defined clinical sensitivity to peanut in a group of peanut-sensitized children.


METHODS
Clinical sensitivity was determined by means of double-blind, placebo-controlled peanut challenges in 24 sensitized children. Six atopic control subjects were included. Specific IgE and IgG4 binding to 419 overlapping 15-amino-acid peptides representing the sequence of recombinant Ara h 1, Ara h 2, and Ara h3 was analyzed by means of microarray immunoassay.


RESULTS
Peanut-sensitized patient sera bound significantly more IgE and IgG4 epitopes than control sera. This patient group reacted to the same Ara h 1, Ara h 2, and Ara h 3 epitopes as reported previously. There was a positive correlation between IgE epitope diversity (ie, number of epitopes recognized) and clinical sensitivity (r = 0.6), such that patients with the greatest epitope diversity were significantly more sensitive than those with the lowest diversity (P = .021). No specific epitopes were associated with severe reactions to peanut. IgG4 binding was observed to largely similar epitopes but was less pronounced than IgE binding and did not relate to the clinical sensitivity to peanut. IgE and IgG4 epitope-recognition patterns were largely stable over a 20-month period.


CONCLUSIONS
Clinical sensitivity, as determined by means of double-blind, placebo-controlled peanut challenge, is positively related to a more polyclonal IgE response, which remains stable over time.
Flinterman
Annebeth E
AE
Department of Dermatology/Allergology, University Medical Centre Utrecht, Utrecht, The Netherlands.
Knol
Edward F
EF
Lencer
Doerthe A
DA
Bardina
Ludmilla
L
den Hartog Jager
Constance F
CF
Lin
Jing
J
Pasmans
Suzanne G M A
SG
Bruijnzeel-Koomen
Carla A F M
CA
Sampson
Hugh A
HA
van Hoffen
Els
E
Shreffler
Wayne G
WG
D000293:Adolescent; D000485:Allergens / Q000276:immunology*; D000918:Antibody Specificity; D010367:Arachis / Q000737:chemistry / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D018985:Epitopes, B-Lymphocyte / Q000737:chemistry / Q000276:immunology*; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood / Q000737:chemistry / Q000276:immunology*; D007074:Immunoglobulin G / Q000097:blood / Q000737:chemistry / Q000276:immunology*; D007223:Infant; D008297:Male; D021183:Peanut Hypersensitivity / Q000097:blood / Q000276:immunology*
D000485:Allergens; D018985:Epitopes, B-Lymphocyte; D007074:Immunoglobulin G; D007073:Immunoglobulin E