WT1-specific CTL cells of recipient origin may exist in the peripheral blood of patients achieving full donor chimerism soon after nonmyeloablative transplantation.

This study was performed to assay whether leukemia-associated antigen (LAA)-specific CTLs of recipient origin existed in the blood of patients who achieved full donor chimerism (FDC) soon after nonmyeloablative transplantation (NST). In 15 patients who received haplo-identical NST, WT1(+) CD8(+) CTLs were detected with WT1/HLA-A*0201 pentamer, and the donor-recipient chimerism levels were analyzed by three methods. Results showed that WT1(+) CD8(+) CTLs could be detected in patients with HLA-A*0201 expressing only in recipient, and cells of recipient origin existed in the blood of patients who achieved FDC, which suggested that LAA-specific CTLs of recipient origin may exist in patients achieving FDC soon after NST.