Selective elimination of leukemic CD34(+) progenitor cells by cytotoxic T lymphocytes specific for WT1

Hematologic malignancies such as acute and chronic myeloid leukemia are cha racterized by the malignant transformation of immature CD34(+) progenitor c ells. Transformation is associated with elevated expression of the Wilm's t umor gene encoded transcription factor (WT1), Here we demonstrate that WT1 can serve as a target for cytotoxic T lymphocytes (CTL) with exquisite spec ificity for leukemic progenitor cells. HLA-A0201-restricted CTL specific fo r WT1 kill leukemia cell lines and inhibit colony formation by transformed CD34(+) progenitor cells isolated from patients with chronic myeloid leukem ia (CML), whereas colony formation by normal CD34(+) progenitor cells is un affected. Thus, the tissue-specific transcription factor WT1 is an ideal ta rget for CTL-mediated purging of leukemic progenitor cells in vitro and for antigen-specific therapy of leukemia and other WT1-expressing malignancies in vivo. (Blood. 2000;95:2198-2203) (C) 2000 by The American Society of He matology.