Flow Cytometric Analysis of TCR-Vbeta Expression in the Evaluation of T-Cell Clonality in Lymph Nodes and Lymphoid Tissues
CM Carter, DM Cardona, Y Li, SZ Al-Quran. University of Florida, Gainesville, FL
Background: Flow cytometric (FCM) analysis of the repertoire of the variable regions in the T cell receptor (TCR) β chain (TCR-Vbeta) has been lately utilized for the detection of T-cell lymphoproliferative disorders (TLPD). Clonal expansions of T cells expressing the αβ TCR are expected to express a single Vβ subfamily. Most published studies have assessed T cell clonality in peripheral blood samples. A recent study demonstrated that the TCR-Vbeta repertoire of reactive T cells is very similar in lymph nodes and blood samples. The aim of our study was to asses the utility of Vbeta analysis in the diagnosis of T cell non-Hodgkin lymphoma (TNHL) and TLPD in lymph nodes (LNs) and lymphoid tissues (LTs).
Design: We retrospectively searched for samples of LNs and LTs received in our flow cytometry laboratory between 1/2003 and 9/2009 that had TCR-Vbeta analysis. We studied 19 LNs and 32 LTs, which included endoscopic biopsies (EBXs) and fine needle aspirates (FNAs). In all cases, TCR-Vbeta analysis was prompted by immunophenotypic/ morphologic abnormalities or clinical information. The data was correlated with molecular results when available, and clinical outcomes were recorded for all patients.
Results: Twenty five cases had a normal/reactive T cell immunophenotype. None of these cases had evidence of T cell clonality by TCR-Vbeta or molecular analyses. To date, none of these patients have developed TNHL/TLPD. T cell clonality was demonstrated by TCR-Vbeta in 23 cases. Three patients had negative TCR-Vbeta and molecular analyses. Based on other laboratory and clinical criteria, 21 cases were diagnosed as TNHL/TLPD. Two patients did not develop TNHL/TLPD; one patient had ITP and the other was lost to follow-up. Three cases had immunophenotypic abnormalities with negative TCR-Vbeta and molecular analyses. Two patients were lost to follow-up, and the remaining patient was diagnosed with B cell lymphoma.
Conclusions: FCM analysis of TCR-Vbeta expression is a very sensitive and powerful technique that can help in the rapid diagnosis of TNHL/TLPD in LNs/LTs in the appropriate morphological and clinical settings. It is unique in the detection of clonal T-cell expansions within heterogeneous samples, and is also applicable to small samples including EBXs and FNAs. Moreover, Vβ-restricted T cell populations can be monitored during and after therapy.
Monday, March 22, 2010 1:00 PM
Poster Session II # 152, Monday Afternoon