Rapid evaluation of T cell clonality in the diagnostic work-up of mature T cell neoplasms: TRBC1-based flow cytometric assay experience

• DOI: 10.1016/j.tranon.2022.101552
• Publication Date: 2022-09-30T00:22:17Z
• Authors: Manuela Capone; Benedetta Peruzzi; Boaz Palterer; Sara Bencini; Alessandro Sanna; Benedetta Puccini; Luca Nassi; Benedetta Salvadori; Marinella Statello; Alessia Carraresi; Stefania Stefanelli; Chiara Orazzini; Barbara Minuti; Roberto Caporale; Francesco Annunziato
• Keywords: 0301 basic medicine; T-cell clonality; T-cell lymphoproliferative diseases/lymphomas; 0303 health sciences; T-cell receptor β chain; Neoplasms. Tumors. Oncology. Including cancer and carcinogens; 3. Good health; 03 medical and health sciences; T-cell clonality; T-cell lymphoproliferative diseases/lymphomas; T-cell receptor β chain; TRBC1; TRBC1; RC254-282; Original Research

The identification of mature T cell neoplasms by flow cytometry is often challenging, due to overlapping features with reactive T cells and limitations of currently available T cell clonality assays. The description of an antibody specific for one of two mutually exclusive T cell receptor (TCR) β-chain constant regions (TRBC1) provides an opportunity to facilitate the detection of clonal TCRαβ+ T cells based on TRBC-restriction. Here we prospectively analyzed 14 healthy controls and 63 patients with the flow cytometry protocol currently used for suspected T cell neoplasm implemented with immunostaining targeting TRBC1. Specimens were firstly classified in 3 groups based on clinical records data, laboratory findings and immunophenotypic features. T cell clonality was assessed by TCR Vβ repertoire analysis and the new rapid TRBC1 assay. Results showed that TRBC1 unimodal expression was unequivocally associated with samples presenting with immunophenotypic aberrancies. Moreover, we demonstrated that the use of TRBC1 is useful in solving uncertain cases and confirmed the high sensitivity of the method in identifying small T cell clones of uncertain significance (T-CUS). Finally, we found a high degree of concordance (97%) comparing the currently available clonality assessment methods with the proposed new method. In conclusion, our results provided real-life evidence of the utility of TRBC1 introduction in the flow cytometric clonality evaluation for the routine diagnostic work-up of T cell neoplasms.