title: Association of allergen-specific regulatory T cells with the onset of clinical tolerance to milk protein.
abstract: BACKGROUND
  About 70% of children with milk allergy tolerate extensively heated milk (HM) products and outgrow their allergy earlier than those who react to HM.
  
  
  OBJECTIVE
  To test the hypothesis that HM-tolerant children have a higher precursor frequency of adaptive allergen-specific regulatory T (Treg) cells.
  
  
  METHODS
  Allergic, HM-tolerant, outgrown, or control subjects were defined by oral food challenge. PBMCs were cultured with purified caseins and controls for 7 days, and proliferating CD25(+)CD27(+) Treg cells were identified by flow cytometry. Proliferating cells were also characterized for their expression of FoxP3, CTLA 4, CD45RO, and CD127. Allergen-specific Treg cell origin and function were assessed by depletion of CD25(hi) cells before culture.
  
  
  RESULTS
  There was a higher percentage (median [25th% to 75th%], 16.85% [7.1-31.7]) of proliferating allergen-specific CD25(+)CD27(+) T cells from cultures of HM-tolerant subjects (n = 18) than subjects with allergy (n = 8; 4.91% [2.6-7.5]; P < .01). Control subjects with no history of milk allergy (n = 7) also had low percentages of these cells (2.9% [2.4-6.0]), whereas outgrown subjects (n = 7) had intermediate percentages (9.0% [2.7-16.4]). There were no significant differences between the patient groups in the frequency of polyclonal Treg cells or allergen-specific effector T cells. Allergen-specific Treg cells were found to be FoxP3(+)CD25(hi)CD27(+), cytotoxic T lymphocyte-associated antigen 4(+), CD45RO(+)CD127(-) and were derived from circulating CD25(hi) T cells. Depletion of the CD25(hi) cells before in vitro culture significantly enhanced allergen-specific effector T-cell expansion.
  
  
  CONCLUSIONS
  A higher frequency of milk allergen-specific Treg cells correlates with a phenotype of mild clinical disease and favorable prognosis.
authors.affiliation: Jaffe Food Allergy Institute, Division of Allergy and Immunology, Department of Pediatrics, New York, NY 10029, USA. wayne.shreffler@mssm.edu
authors.forename: Wayne G
authors.initials: WG
authors.lastname: Shreffler
authors.forename: Niya
authors.initials: N
authors.lastname: Wanich
authors.forename: Marla
authors.initials: M
authors.lastname: Moloney
authors.forename: Anna
authors.initials: A
authors.lastname: Nowak-Wegrzyn
authors.forename: Hugh A
authors.initials: HA
authors.lastname: Sampson
mesh_terms: D000293:Adolescent; D000485:Allergens / Q000276:immunology*; D000943:Antigens, Differentiation / Q000096:biosynthesis / Q000276:immunology*; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D005260:Female; D005786:Gene Expression Regulation / Q000276:immunology*; D006801:Humans; D007108:Immune Tolerance / Q000276:immunology*; D008212:Lymphocyte Depletion; D008297:Male; D016269:Milk Hypersensitivity / Q000175:diagnosis / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D011379:Prognosis; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism
chemical_list: D000485:Allergens; D000943:Antigens, Differentiation