AbstractObjectivesFlow cytometry immunophenotyping is limited by poor resolution of T-cell clones. A newly described antibody was recently used to distinguish normal peripheral blood T cells from malignant T-cell clones. Here, we evaluate this antibody as a new diagnostic tool for detecting T-cell clonality in mature peripheral T-cell lymphomas.MethodsImmunostaining for the T-cell receptor β chain constant region 1 (TRBC1) along with routine T-cell markers was performed on 51 peripheral blood and two bone marrow samples submitted to the flow cytometry laboratory for suspected T-cell malignancy.ResultsTRBC immunophenotyping identified malignant T-cell clones with 97% sensitivity and 91% specificity. Findings correlated with molecular T-cell clonality testing. In cases with equivocal molecular results, TRBC1 immunophenotyping provided additional diagnostic information.ConclusionsTRBC1 flow cytometric immunophenotyping is a robust and inexpensive method for identifying T-cell clonality that could easily be incorporated into routine flow cytometric practice.
Peripheral T-cell lymphomas of follicular helper T-cell type frequently display an aberrant CD3−/dimCD4+ population by flow cytometry: an important clue to the diagnosis of a Hodgkin lymphoma mimic