biostudies-literatureMunoz-Garcia NINTERREG POCTEP Spain-PortugalFondo Europeo de Desarrollo RegionalInstituto de Salud Carlos IIICentro de Investigación Biomédica en Red de Cáncer408https://www.ebi.ac.uk/biostudies/studies/S-EPMC8773687biostudies-literatureUnknown14(2)Flow cytometric (FCM) analysis of the constant region 1 of the T-cell receptor β chain (TRBC1) expression for assessing Tαβ-cell clonality has been recently validated. However, its utility for the diagnosis of clonality of T-large granular lymphocytic leukemia (T-LGLL) needs to be confirmed, since more mature Tαβ cells (i.e., T-LGL normal-counterpart) show broader TRBC1+/TRBC1- ratios vs. total Tαβ cells. We compared the distribution and absolute counts of TRBC1+ and TRBC1- Tαβ-LGL in blood containing polyclonal (n = 25) vs. clonal (n = 29) LGL. Overall, polyclonal TRBC1+ or TRBC1- Tαβ-LGL ranged between 0.36 and 571 cells/μL (3.2-91% TRBC1+ cells), whereas the clonal LGL cases showed between 51 and 11,678 cells/μL (<0.9% or >96% TRBC1+ cells). Among the distinct TCRVβ families, the CD28- effector-memory and terminal-effector polyclonal Tαβ cells ranged between 0 and 25 TRBC1+ or TRBC1- cells/μL and between 0 and 100% TRBC1+ cells, while clonal LGL ranged between 32 and 5515 TRBC1+ or TRBC1- cells/μL, representing <1.6% or >98% TRBC1+ cells. Our data support the utility of the TRBC1-FCM assay for detecting T-cell clonality in expansions of Tαβ-LGL suspected of T-LGLL based on altered percentages of TRBC1+ Tαβ cells. However, in the absence of lymphocytosis or in the case of TαβCD4-LGL expansion, the detection of increased absolute cell counts by the TRBC1-FCM assay for more accurately defined subpopulations of Tαβ-LGL-expressing individual TCRVβ families, allows the detection of T-cell clonality, even in the absence of phenotypic aberrations.CancersHigh-Sensitive TRBC1-Based Flow Cytometric Assessment of T-Cell Clonality in Tαβ-Large Granular Lymphocytic Leukemia.PMC87736870639-IDIAL-NET-3-3CB16/12/00400EuroFlowPI20-01346IBPredoc17/00012Mateos SMoran-Plata FJvan Dongen JJMLima MBarrena SMunoz-Garcia NVillamor NAlmeida JOrfao ACaldas CfalseHigh-Sensitive TRBC1-Based Flow Cytometric Assessment of T-Cell Clonality in Tαβ-Large Granular Lymphocytic Leukemia.Flow cytometric (FCM) analysis of the constant region 1 of the T-cell receptor β chain (TRBC1) expression for assessing Tαβ-cell clonality has been recently validated. However, its utility for the diagnosis of clonality of T-large granular lymphocytic leukemia (T-LGLL) needs to be confirmed, since more mature Tαβ cells (i.e., T-LGL normal-counterpart) show broader TRBC1+/TRBC1- ratios vs. total Tαβ cells. We compared the distribution and absolute counts of TRBC1+ and TRBC1- Tαβ-LGL in blood containing polyclonal (n = 25) vs. clonal (n = 29) LGL. Overall, polyclonal TRBC1+ or TRBC1- Tαβ-LGL ranged between 0.36 and 571 cells/μL (3.2-91% TRBC1+ cells), whereas the clonal LGL cases showed between 51 and 11,678 cells/μL (<0.9% or >96% TRBC1+ cells). Among the distinct TCRVβ families, the CD28- effector-memory and terminal-effector polyclonal Tαβ cells ranged between 0 and 25 TRBC1+ or TRBC1- cells/μL and between 0 and 100% TRBC1+ cells, while clonal LGL ranged between 32 and 5515 TRBC1+ or TRBC1- cells/μL, representing <1.6% or >98% TRBC1+ cells. Our data support the utility of the TRBC1-FCM assay for detecting T-cell clonality in expansions of Tαβ-LGL suspected of T-LGLL based on altered percentages of TRBC1+ Tαβ cells. However, in the absence of lymphocytosis or in the case of TαβCD4-LGL expansion, the detection of increased absolute cell counts by the TRBC1-FCM assay for more accurately defined subpopulations of Tαβ-LGL-expressing individual TCRVβ families, allows the detection of T-cell clonality, even in the absence of phenotypic aberrations.2022-01-01T00:00:00Z2022 Jan2024-02-15T07:27:10.983Z2022-02-11T16:04:53.126ZS-EPMC87736873505357110.3390/cancers14020408