[Analysis of Immunophenotype and Clinical Biological Characteristics of Mature T-Cell Lymphoma and Clonal T Cells of Undetermined Significance].

[OBJECTIVE] To analyze the immunophenotype and clinical characteristics of mature T-cell lymphoma (TCL) and clonal T cells of undetermined significance (T-CUS), and to explore the application value of flow cytometry in the differential diagnosis of TCL and T-CUS.

[METHODS] Multi-parameter flow cytometry (MFC) was used to analyze the immunophenotypic characteristics of 93 TCL patients (TCL group) and 46 patients with T-CUS but no T-lymphoproliferative disease (non-TCL group) admitted to the Department of Hematology of Henan Provincial People's Hospital from October 2019 to June 2024, and the clinical and laboratory data of patients in TCL group and T-CUS group (non-TCL patients) were collected.

[RESULTS] In terms of flow cytometry immunophenotype, the TCL group and the T-CUS group had similar immunophenotypes, with CD8 tumor cells being the most, followed by CD4, and CD4/CD8 and CD4/CD8 being rare. There were significant statistical differences in the positive expression rates of CD3, CD4 and CD8 between the two groups, which showed that the expression rates of CD3 and CD8 in the TCL group were lower than those in the T-CUS group (CD3: 72.00±42.04 94.05±21.61; CD8: 56.04±48.22 79.86±36.33) ( <0.05), while the expression rates of CD4 were higher than those in the T-CUS group ［（38.35±48.53） （10.76±31.15）, ( <0.01)］. TRBC1 showed a restricted expression pattern (monoclonal expression) in all cases, and the positive expression rate of TRBC1 in the TCL group was slightly higher than that in the T-CUS group, but there was no significant statistical difference between the two group ( >0.05). According to the laboratory results, the levels of RDW-CV and LDH in the TCL group were higher than those in the T-CUS group ［RDW-CV: 17.6(11.9-24) 14.1(10.9-19.1); LDH: 459(129-90 704) 310(99-11 722)］, and the difference was statistically significant ( <0.05). The results of T-cell receptor (TCR) gene rearrangement, karyotype analysis and EBV nucleic acid quantitative detection were obtained in the two groups, and the Kappa test showed that the positive rate of TCR gene rearrangement in the TCL group was significantly higher than that in the T-CUS group (92.1% 52.6%) ( <0.001).

[CONCLUSION] TRBC1 can be used as an ideal indicator for rapid detection of T cell clonality, Multi-parameter flow cytometry (MFC) combined with TCR gene rearrangement testing has good clinical value in distinguishing T-cell lymphoma from T-cell clonal proliferation of uncertain significance.