Background:
We have previously established tumour t-cell lines, both from the skin and from the blood of patients with a cutaneous t-cell lymphoma (ctcl). in one patient, the tumour cells and the derived cell lines had a cd3+ cd4+ cd8- phenotype and a trisomy of chromosome 7. they expressed three t-cell receptor (tcr) beta-chain transcripts, but only one was productively rearranged and expressed at the cell membrane.
Objectives:
In the present study, we tried to isolate a fast-growing new tumour t-cell line from the same patient.
Patients/methods:
We performed direct cell cloning of the skin tumour lymphocyte population, which led to the isolation of an interleukin-2-dependent highly proliferative t-cell subclone, named cou-l3, with a cd3+ tcr-vbeta13+ cd4- cd8alphaalpha+ phenotype.
Results:
We demonstrated that cou-l3 was identical to the original clonal tumour cd3+ vbeta13+ cd4+ cd8- cells, as it expressed the same rearranged tcr-vbeta13 chain. we further studied the functional activity of these cd8alphaalpha+ vbeta13+ cou-l3 cells. we found that these cells exhibited cd3-redirected cytotoxic activity.
Conclusions:
An immunophenotypic shift, with a change from a cd4+ to a cd8+ phenotype, has been already reported in association with disease progression in ctcl. however, in these cases, there has been no demonstration that the phenotypic change involved the same t-cell clone. the present study is the first report of the phenotypic heterogeneity of the tumour clonal cell population in ctcl.