Yamanaka KI, Yawalkar N, Jones DA, Hurwitz D, Ferenczi K, Eapen S, Kupper TS. Decreased T-Cell Receptor Excision Circles in Cutaneous T-Cell Lymphoma.
Clin Cancer Res 2005;
11:5748-55. [PMID:
16115912 DOI:
10.1158/1078-0432.ccr-04-2514]
[Citation(s) in RCA: 30] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE
The T cell repertoire in patients with advanced cutaneous T cell lymphoma (CTCL) is significantly contracted despite the presence of relatively normal absolute numbers of T cells. We propose that many normal T cells were being lost in patients with CTCL, with the remaining normal T cells expanding clonally to fill the T cell compartment. T-cell receptor excision circles (TREC) form as a result of the initial gene rearrangement in naïve T cells. Although they are stable, they do not replicate and are subsequently diluted with the expansion of a population of T cells. Their concentration is therefore a measure of unexpanded naïve T cells relative to T cells that have undergone expansion.
EXPERIMENTAL DESIGN
We analyzed TRECs from unfractionated peripheral blood T cells from 108 CTCL patients by quantitative PCR. In patients with obvious peripheral blood involvement, we also analyzed TRECs from clonal and nonclonal T cells.
RESULTS
We found a decrease in the number of TRECs in peripheral blood of patients with CTCL at all stages of disease, and this decrease was proportional to the loss of complexity of the T cell repertoire as measured by complementarity-determining region 3 spectratyping. In patients with leukemic CTCL and a numerically expanded clone, we also found a significantly lower-than-expected number of TRECs in the nonclonal normal T cells.
CONCLUSIONS
We hypothesize that the nonmalignant T cells have proliferated to fill the empty T cell repertoire space left by the loss of other T cells, leading to diminished TRECs and loss of T-cell receptor diversity.
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