Integration of T-cell clonality screening using TRBC-1 in lymphoma suspect samples by flow cytometry

Background: The diagnosis of T-cell non-Hodgkin lymphomas (NHL) is challenging. The development of a monoclonal antibody specific for T-cell receptor beta constant region 1 (TRBC1) provides an alternative to discriminate clonal T cells. The aim of this study was to evaluate the diagnostic potential of an anti-TRBC1 mAb for the identification of T-NHL.Methods: We performed a cross-sectional diagnostic analytic study of samples tested for lymphoma. All samples sent for lymphoma screening were first evaluated using the standard Euroflow LST, to which a second additional custom-designed T-cell clonality assessment tube was added CD45/TRBC1/CD2/CD7/CD4/TCR gamma delta/CD3. Flow cytometry reports were compared with morphological and molecular tests.Results: Fifty-nine patient samples were evaluated. Within the T-cell population, cut-off percentages in the CD4+ cells were from 29.4 to 54.6% and from 23.9 to 52.1% in CD8+ cells. Cut-off ratios in CD4+ T cells were from 0.33 to 1.1, and in CD8+ cells between 0.22 and 1.0. Using predefined normal cut-off values, 18 of 59 (30.5%) samples showed a restricted expression of TRBC1. A final diagnosis of a T-NHL was confirmed clinically and/or by histopathological studies in 15 of the 18 cases (83.3%). There were no cases of T-NHL by morphology/IHC with normal TRBC1 expression. Non-neoplastic patient samples behaved between predefined TRBC1 cut-off values.Conclusions: Expression of TRBC1 provides a robust method for T-cell clonality assessment, with very high sensitivity and good correlation with complementary methods. TRBC1 can be integrated into routine lymphoma screening strategies via flow cytometry.

Automated summary

This study evaluated the diagnostic potential of an anti-TRBC1 monoclonal antibody for the identification of T-cell non-Hodgkin lymphomas (NHL). Flow cytometry analysis showed that TRBC1 expression provides a robust method for T-cell clonality assessment with high sensitivity and good correlation with complementary methods. The findings suggest that TRBC1 can be integrated into routine lymphoma screening strategies.