DEMONSTRATION OF CLONAL DISEASE IN EARLY MYCOSIS-FUNGOIDES

Cutaneous T-cell lymphomas (CTCLs) are known to show monoclonal T-cell infiltrates late in the course of the disease. However, detection of monoclonal T-cell proliferation in early stages is difficult. To investigate the possibility that clones might appear only as minor subpopulations, we analyzed the proliferative activity of T cells expressing certain variable (V) regions of the T-cell receptor (TCR). In biopsy specimens from 27 patients with CTCLs, all T cells expressing the V regions V-alpha-2, V-beta-5a, V-beta-5b, V-beta-6, V-beta-8, and V-beta-12 accounted for < 5% of the total infiltrate. In the vast majority of the cases, < 3% of the cells expressing one TCR V region proliferated. In one case of mycosis fungoides, however, an epidermotropic clone expressing V-beta-8 was detected. This clone was present in two distinct lesions from different anatomic sites and was found in an early relapse 1 year after complete remission following PUVA therapy. The case described here documents the possibility of clonal disease early in the course of mycosis fungoides.