The Utility of Flow Cytometry TCR-V Chain Analysis in Combination with Immunophenotyping for Assessing Blood Involvement by Cutaneous T-cell Lymphoma (CTCL)
B Feng, JL Jorgensen, DM Jones, LJ Medeiros, SAA Wang. UT MD Anderson Cancer Center, Houston, TX
Background: Blood involvement by tumor cells has adverse prognostic significance in patients with CTCL. Since the tumor-cells frequently show nonspecific morphology, clonality testing is required for confirmation. Commonly used TCR gene PCR has long turn-around time and can detect non-neoplastic clonal rearrangement. We assess the clinical usefulness of TCR-V flow cytometry analysis as a replacement technique for CTCL-blood staging.
Design: We studied the blood samples of 88 CTCL patients and 18 controls using a panel of TCR-V antibodies covering 70% of the TCR-V segments. To improve sensitivity, TCR-V was analyzed on abnormal T-cells with aberrant CD3, CD4 or CD26 expression. TCR- and TCR- chain PCR testing were conducted in 40 cases in parallel. Circulating CTCL was determined by morphology, immunophenotype and clonality.
Results: Of the 88 samples, Sezary cells identified by manual differential were of 0-5% in 54(61%); 5-19% in 17(19%) and >20% in 17(19%) patients. Immunophenotypic aberrancies were detected in 23/54, 14/17 and 14/17 of these patients. Abnormal TCR-V was detected in 32/54, 17/17 and 17/17 of the CTCL cases but not in the controls, demonstrating a 92% concordance with blood involvement, similar to TCR gene PCR but with superior specificity (100% vs 75%). 44 cases had detectable tumor-associated V expression permitting the use for follow-up studies.
Table 1. Correlation of Abnormal Cells Detected by Morphology, Immunophenotyping, Vbeta, and TCR Gene Rearrangement
|%Sezary cells by morphology||Control(n=18)||<5% (n=54)||5-19% (n=17)||>20% (n=17)|
|SS by CD4 CD3dim CD7- CD26-|
|Tumor cells by V beta|
|TCR gene rearrangement|
Conclusions: TCR-V chain analysis in combination with immunophenotyping improves the detection sensitivity and allows a definite identification of tumor cell-defining blood involvement. The V flow cytometry analysis is rapid, quantitative and suitable for monitoring tumor load during therapy.
Monday, March 9, 2009 11:15 AM
Platform Session: Section D, Monday Morning