Analysis of the proliferative and phenotypic properties of tumor infiltrating lymphocytes expanded in vitro in the course of the clinical trial of adoptive immunotherapy of metastatic melanoma.

Adoptive immunotherapy with in vitro expanded tumor infiltrating lymphocytes (TIL) and recombinant interleukin-2 (rIL-2) is a recent option in the treatment of advanced melanoma resistant to conventional chemotherapy. In the course of a protocol of treatment of advanced melanoma with in vitro expanded TIL and rIL-2, we obtained 38 samples from 27 different patients. Lymphocytes derived were cultured in the presence of rIL-2 in vitro for a 4-6 week period and 23 resulted in proliferative cultures. Eighteen samples were infused in the course of the clinical trial. The median number of lymphocytes obtained was 18x10(9) (range 1-43x10(9)) cells. Phenotypic analysis showed that all samples contained a pure population of T cells. These data confirm that lymphocytes can be expanded from advanced metastatic sites, have peculiar characteristics and are suitable to be infused in vivo.