Flow cytometric evaluation of TRBC1 expression in tissue specimens and body fluids is a novel and specific method for assessment of T-cell clonality and diagnosis of T-cell neoplasms

Cytometry B Clin Cytom. 2021 May;100(3):361-369. doi: 10.1002/cyto.b.21881. Epub 2020 Apr 25.


Background: Flow cytometric detection of T-cell clonality is challenging. The current available methodology for T-cell receptor (TCR) Vβ repertoire evaluation is a complex assay and has limited sensitivity especially for detecting low levels of disease. Therefore, there is an unmet need for a reliable, simple, and rapid assay to identify T-cell clonality. The rearrangement of the TCRB gene involves the random and mutually exclusive expression of one of two constant β chain genes (TRBC1 and TRBC2), analogous to the kappa and lambda gene utilization by B cells.

Methods: Here, we used a single TRBC1 antibody, in conjunction with other T-cell associated markers, to detect T-cell clonality in tissue biopsies and body fluids. A total of 143 tissue/body fluid specimens from 46 patients with a definitive diagnosis of a T-cell neoplasm and 97 patients with no T-cell malignancy were analyzed with a cocktail of monoclonal antibodies including CD2/CD3/CD4/CD5/CD7/CD8/CD45/TCRγδ/TRBC1.

Results: We examined TRBC1 expression on neoplastic T-cell populations identified based on their immunophenotypic aberrancies, and monotypic TRBC1 expression was identified in all 46 known T-cell lymphoma cases. We applied a similar gating strategy to the 97 cases without T-cell neoplasms, and arbitrarily dissected T-cell populations into immunophenotypically distinct subsets; in this group, we found that all cases revealed an expected polytypic TRBC1 expression in all subsets.

Conclusions: Single TRBC1 antibody detection of T-cell clonality by flow cytometry is a simple, rapid, and robust assay that could be routinely utilized in flow cytometric laboratories.

Keywords: T-cell clonality; T-cell neoplasms; TRBC1; flow cytometry.

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Aged, 80 and over
  • Antibodies, Monoclonal / metabolism
  • Body Fluids / metabolism*
  • Female
  • Flow Cytometry / methods
  • Humans
  • Immunophenotyping / methods
  • Lymphoma, T-Cell / diagnosis*
  • Lymphoma, T-Cell / metabolism*
  • Male
  • Middle Aged
  • Receptors, Antigen, T-Cell, alpha-beta / metabolism*
  • Receptors, Antigen, T-Cell, gamma-delta / metabolism
  • T-Lymphocytes / metabolism*
  • Young Adult


  • Antibodies, Monoclonal
  • Receptors, Antigen, T-Cell, alpha-beta
  • Receptors, Antigen, T-Cell, gamma-delta
  • TRBC1 protein, human