Therapeutic CSF Primed Donor Lymphocyte Infusion Using Cells Reserved at the Time of Transplantation for Patients with Relapsed Hematologic Malignancies after allo-PBSCT.

Background

Reharvesting leukocytes from donors for a donor lymphocyte infusion (DLI) is inconvenient and occasionally impossible in case of unrelated donors. The effect of a growth factor-primed DLI is known to be comparable to that of nonprimed DLI for patients with relapsed disease. We reserved some portion of PBSCs harvested at the time of transplantation for the purpose of future DLI for relaping disease.

Method

In total, ninety nine patients (43 high risk, 46 standard disease) with hematologic malignancies who were treated by allo-PBSCT were allocated on an intent-to-treat basis. The dose of CD34+ cells with a range of 2–6*10⁶/kg was transplanted, and additional PBSCs were cryopreserved.

Result

PBSC harvest for transplantation allowed to reserve extra cells in 35 (67.3%) high risk patients and in low risk 25 (55.6%) patients. Among 29 patients (29.9%) who relapsed after allogeneic PBSCT, 19 (65.5%) patients were treated with mainly cytarabine-based chemotherapy followed by cryopreserved PBSC infusion. The median dose of CD3+ and CD34+ cells for the primed DLI was 1.43*10⁸/kg and 4.75*10⁶/kg, respectively. Six (24.9%) out of 19 relapsed patients exhibited a complete response after the primed DLI, and their 1-year survival rate was 36%. The new development or progression of graft-versus-host disease after the primed DLI was observed in 16 (82%) patients. Overall, the survival at 1 year after the primed DLI was 21%.

Conclusion

The induction of a graft-versus-leukemia effect through a primed DLI, using additional PBSCs reserved at the time of transplantation, would appear to be feasible for patients with relapsed hematologic malignancies. Furthermore, this approach seem to be more convenient for donors.