Clinical Experience With Modified, Single-Tube T-Cell Receptor Vβ Flow Cytometry Analysis for T-Cell Clonality

Analysis of T-cell clonality using the IO Test Beta Mark (Beckman Coulter, Fullerton, CA) flow cytometry assay is cumbersome owing to the required eight-part analyses that limit its clinical utility. Here, we describe a simple modification that may improve its clinical utility.

By simply combining all T-cell receptor (TCR) Vβ antibodies into one reagent tube, we show that T-cell repertoire analysis can be efficiently performed with an increased potential to closely link the aberrant immunophenotype of a neoplastic T-cell clone to its apparent clonal TCR Vβ restriction. We review our clinical experience and include flow cytometry sorting studies in conjunction with TRG gene rearrangement analysis to demonstrate the feasibility of this approach.

We show in representative cases that this modified approach permits evaluation of TCR Vβ clonality in T-cell neoplasms without a priori knowledge of the TCR Vβ isoform restriction and that this approach is suitable for samples containing a minor population of neoplastic T cells, hypocellular samples such as skin biopsy specimens and body fluids, and fine-needle aspirations. We estimate a false-positive rate for identifying a clonal population for this approach to be less than 6.2%.

Our modified approach of TCR Vβ analysis could improve routine clinical evaluation for abnormal T-cell populations by flow cytometry.