title: T-cell receptor phenotype pattern in atopic children using commercial fluorescently labeled antibodies against 21 human class-specific v segments for the tcrβ chain (vβ) of peripheral blood: a cross sectional study.
abstract: BACKGROUND
  T-cell receptor (TCR) repertoire development is an integral part of the adaptive immune response. T-cell activation requires recognition of appropriately processed antigens by the TCR. Development of a diverse repertoire of TCRs is therefore essential to ensure adequate protection from potential threats. The majority of T-cells in peripheral blood have TCRs composed of an alpha and a beta chain. At the DNA level, the TCR genes are formed through directed recombination from germline sequences-the so-called VDJ recombination [variable (V) joining (J) diversity (D) gene segments] which results in variations in the repertoire. The most variable part of TCRs is the Vβ region (VβTCR), which has multiple V segment families that can be quantitatively measured. However, only sparse data exists on the normal levels of the VβTCR repertoire in healthy children. We aimed to establish normal values for the VβTCR repertoire in atopic children without immunodeficiency.
  
  
  METHODS
  Fifty-three children were recruited from food allergy, drug allergy, chronic urticaria and anaphylaxis registries and were divided into groups based on age: >0-2 years, 3-6 years, and 6-18 years. We used commercially available and fluorescently labeled antibodies against 21 human class-specific V segments of the TCRβ chain (Vβ) to study in peripheral blood the quantitative pattern of Vβ variation by flow cytometry.
  
  
  RESULTS
  Children of all ages exhibited a similar pattern of TCR Vβ expression. Vβ 2 was the most commonly expressed family in all three age groups [9.5 % (95 % CI, 8.9, 10 %), 8.8 % (95 % CI, 7.4, 10.2 %) and 7.6 % (7.0, 8.3 %) respectively]. However, the percentage of Vβ 2 decreased in older children and the percentage of Vβ 1 was higher in males. TCR Vβ expression in our sample of atopic children did not differ substantially from previously published levels in non-atopic cohorts.
  
  
  CONCLUSIONS
  TCR Vβ diversity follows a predictable and comparable pattern in atopic and healthy non-atopic children. Establishing normal levels for healthy children with and without atopy will contribute to a better definition of Vβ receptor deviation in children with primary immunodeficiency and/or immunodysregulation conditions.
authors.affiliation: Division of Allergy and Clinical Immunology, Department of Pediatrics, Montreal Children's Hospital, McGill University, 1001 Boulevard Décarie, Room A 02.2227, Montréal, QC H4A 3J1 Canada.
authors.forename: Gassem
authors.initials: G
authors.lastname: Gohal
authors.affiliation: Division of Allergy and Clinical Immunology, Department of Pediatrics, Montreal Children's Hospital, McGill University, 1001 Boulevard Décarie, Room A 02.2227, Montréal, QC H4A 3J1 Canada.
authors.forename: Christine
authors.initials: C
authors.lastname: McCusker
authors.affiliation: McGill University Health Center, 1001 Decarie Blvd Room EM3-2232, Montreal, QC H4A 3J1 Canada.
authors.forename: Bruce
authors.initials: B
authors.lastname: Mazer
authors.affiliation: Division of Allergy and Clinical Immunology, Department of Pediatrics, Montreal Children's Hospital, McGill University, 1001 Boulevard Décarie, Room A 02.2227, Montréal, QC H4A 3J1 Canada.
authors.forename: Reza
authors.initials: R
authors.lastname: Alizadehfar
authors.affiliation: Division of Allergy and Clinical Immunology, Department of Pediatrics, Montreal Children's Hospital, McGill University, 1001 Boulevard Décarie, Room A 02.2227, Montréal, QC H4A 3J1 Canada.
authors.forename: Duncan
authors.initials: D
authors.lastname: Lejtenyi
authors.affiliation: Division of Allergy and Clinical Immunology, Department of Pediatrics, Montreal Children's Hospital, McGill University, 1001 Boulevard Décarie, Room A 02.2227, Montréal, QC H4A 3J1 Canada.
authors.forename: Moshe
authors.initials: M
authors.lastname: Ben-Shoshan