Investigating Mature T-Cell Clonality by Flow Cytometry Using Novel Anti-TRBC1

December 2022
Ampath | ampath.co.za

Introduction

Ampath has incorporated a novel flow cytometry marker, TRBC1 (T-cell receptor β-chain constant region 1), into its diagnostic panels for the investigation of mature αβ T-cell lymphoid proliferations.

Why Use TRBC1?

• Fast
• Cost-effective
• Robust method for assessing αβ T-cell clonality
• Supports the diagnosis of T-cell neoplasia

How TRBC1 Flow Cytometry Works

• The TRβ gene rearrangement occurs in the thymus and results in mutually exclusive expression of TRBC1 or TRBC2.
• In reactive (polyclonal) T-cell proliferations, both TRBC1 and TRBC2 are expressed — this shows up as bimodal expression.
• In clonal T-cell populations, only one of TRBC1 or TRBC2 is expressed, showing monotypia.
• The principle is similar to kappa/lambda light chain ratio analysis in B-cells.

TRBC1 Flow Cytometry Panel Overview

TRBC1 expression is assessed alongside key pan T-cell markers, including:

• Surface CD3
• CD4
• CD8
• CD2
• CD5
• CD7
• CD45
• TCRγδ (to exclude γδ T-cells)

Also included:

• CD56
• CD38
• Lymphoid screening tube (LST)

Assessment Focus:

• Mature αβ T-cell subsets
• Identification of monotypia
• Detection of aberrant antigen expression
• Exclusion of mature γδ T-cell populations

Benefits of TRBC1 Assessment

• Broad applicability: Most mature T-lymphoid proliferations express TCRαβ
• Sample flexibility:
  • Blood
  • Bone marrow
  • Body fluids
• Compared to PCR-based gene rearrangement:
  • TRBC1 is faster
  • More cost-effective
  • Less complex
  • Provides information on clone size, which PCR does not

Conclusion

A new, efficient flow cytometry assay using anti-TRBC1 is now available at Ampath for patients with suspected clonal mature αβ T-cell lymphoid proliferation.

📞 Contact:
Flow Cytometry Laboratory
Tel: 012 678 0587