Diagnostic value of detecting TCR variable region subfamily for patients with mature T cell lymphoma / 中华检验医学杂志

ABSTRACT

Objective:To investigate the expression pattern of TCR variable region subfamily (Vβ and Vδ) in patients with mature T-cell lymphoma (TCL), and to compare the diagnostic value of TCRVβ and TCRVδ analysis in TCL.Methods:The TCRVβ flow cytometry kit was used to detect the expression of Vβ subtypes of αβT cell in 199 patients with αβ TCL and 398 patients with non-TCL, who hospitalized in Jiangsu Provincial People Hospital from 2011 to 2020. Among them, 185 cases of αβ TCL and 355 cases of non-TCL also underwent TCRβ and TCRγ gene rearrangement detection. The TCRVδ based 10-color protocol was used to detect the expression of Vδ subtypes in 24 cases of γδTCL, 10 cases of normal controls, and 15 cases with reactively higher CD4 and CD8 double-negative ratio from 2017 to 2020, and 24 cases of γδTCL and 15 cases with reactively higher CD4 and CD8 double-negative ratio underwent TCRβ, TCRγ and TCRδ gene rearrangement detection. The diagnostic performance and degree of coincidence for detecting malignant clonality were compared between TCRVβ and TCRVδ analysis and the TCR gene scanning method.Results:In the 199 cases of αβ TCL, 182 cases (91.5%) showed restricted expression or the sum of the positive percentages of the subgroups was less than 30% for the 24 TCRVβ subtypes. Among them, the subfamily members with the highest incidence of clonal T lymphocytes were TCRVβ13.2 (12.6%, 23/182) and TCRVβ3 (8.2%,15/182); the TCRVβ subtypes showed nonclonal results in 99.0% (394/398) of non-TCL. All 24 cases of γδTCL (100%) showed abnormal distribution patterns of Vδ1 and Vδ2, of which 19 cases showed restricted expression of Vδ1, and the remaining 5 cases had negative expression of either Vδ1 or Vδ2, and the positive rate of Vδ1 cells was significantly higher than that of Vδ2 cells (79.9%±10.8% vs 0.7%±0.3%, P<0.001). Among the normal control and cases with reactively higher CD4 and CD8 double-negative ratio, the positive rate of Vδ2 cells was significantly higher than that of Vδ1 cells (73.7%±6.7% vs 15.6%±4.2%, P<0.001), and all cases (25/25) showed a normal distribution pattern. In terms of the diagnostic performance of TCL, there was no significant difference of sensitivity and specificity between TCR variable region subfamily detection by flow cytometry and TCR gene scanning technology (the sensitivity was 92.4% and 91.4% respectively; the specificity was 99.0% and 95.9% respectively, P=0.065), and the coincidence rate of the two diagnostic methods is high (Kappa=0.809, P<0.001). Conclusion:Detection of TCR variable region subfamily by flow cytometry could quickly and effectively diagnose mature TCL.