Pre-T cell lineage of hand-mirror cells in acute lymphoblastic leukemia.

Acute lymphoblastic leukemia was observed in a 64-year-old male patient with 50-80% hand-mirror cells in the peripheral blood and in the bone marrow. Immunologic surface marker tests indicated that the cells were non-T non-B lymphocytes; however, the addition of thymosin (fraction V) to the bone marrow cells induced the capability of mounting a positive local xenogeneic graft-versus-host reaction (GVHR), demonstrating the pre-T-cell lineage of the hand-mirror cells in this patient.