Genotypic analysis of T-cell clones derived from cutaneous T-cell lymphoma lesions demonstrates selective growth of tumor-infiltrating lymphocytes.

The nature of T cells contained within cutaneous lesions of cutaneous T-cell lymphoma (CTCL) has not been studied at the clonal level. T cells extracted from skin lesions of two CTCL patients were cloned by limiting dilution and propagated in interleukin-2 (IL-2) containing medium with periodic lectin stimulation. Twelve T-cell clones were derived from each patient. In both cases, genotypic analysis of the T-cell clones revealed that these clones had T-cell receptor (TCR) beta- and gamma-chain gene rearrangements distinct from the predominant, presumably malignant, clone present in the skin, lymph nodes, or blood. This suggests that they were derived from presumably reactive (non-malignant) T cells. Furthermore, these clones had gene rearrangements different from each other, indicating their multiple clonal origins. The failure to propagate in vitro the CTCL T-cell clone suggests that CTCL cells may have growth requirements different from normal T cells. Thus, conventional T-cell culturing methods using IL-2 and lectins as mitogen may selectively propagate the presumably reactive T cells contained within the skin lesions. The ability to selectively grow these reactive lesional T cells (so-called tumor infiltrating lymphocytes) raises the possibility that these cells could be used in adoptive immunotherapy.