Retrospective review of TCR-Vβ analysis by flow cytometry and proposed use of screening method

Abstract

Background: Flow cytometric analysis of the TCR-Vβ repertoire can help to determine T cell clonality. The most useful application is in the early diagnosis of T cell neoplasms. Methods: All TCR Vβ assays performed between 2010–2019 at John Hunter Hospital Laboratory were included. 24 Vβ families were tested, gated on CD4 or CD8 cells. Results: 37 Vβ assays were performed on 36 patients. 35 tests were performed on blood, with 2 on tissue. 3 cases were paediatric. The distribution of results were: 20 monoclonal, 5 suspected and 12 polyclonal. The final clinical diagnoses will be presented. Discussion: In the monoclonal and suspicious groups, abnormalities in Vβ4, Vβ14 and Vβ17 were most frequently found. If screening using only these specificities, a total percentage of <3% or >58% was suspicious of clonality and should prompt full TCR-Vβ testing. Based on the samples audited, this screening method has a sensitivity of 96% and specificity of 91%. Conclusion: TCR-Vβ analysis by flow cytometry is a rapid quantitative method to determine T cell clonality. We propose the use of a screening method using 3 Vβ antibodies in one tube, with further characterisation if warranted. Further studies are needed.