In relapsed patients after lymphocyte depleted bone marrow transplantation the percentage of donor T lymphocytes correlates well with the outcome of donor leukocyte infusion.

Donor leukocyte infusions (DLI) from the original marrow donor have been shown to induce remission in patients with relapse after BMT. We analyzed factors that were associated with remission. Twenty-six patients with a relapse after T cell depleted BMT received DLI. The following pre-DLI factors were analyzed: sex and age of the patients and donors, GVHD after BMT, indication for DLI, percentage of donor T lymphocytes in the patient at the time of DLI, interval between relapse and DLI, and number of T lymphocytes infused. Remission was achieved in 11 of 15 patients (73%) treated for relapsed CML and in one of 11 patients (9%) treated for relapsed AML, ALL or RAEB-t (P = .002). Two of 13 patients (15%) with < or =40% of T lymphocytes from donor origin attained remission compared with 10 of 13 patients (77%) with >40% (P = .002). Two of 13 patients (15%) with an interval of < or =18 months between BMT and first DLI entered remission compared with 10 of 13 patients (77%) with an interval of >18 months (P = .002). Multivariate analysis demonstrated that indication for DLI (CML versus AML/ALL and RAEB-t) and the percentage T lymphocytes from donor origin (< or =40 versus >40) were significantly correlated with remission (P = .03). The occurrence of GVHD post DLI was highly associated with achievement of remission (P = .0001). DLI res ults in remission in a high percentage of patients with relapsed CML after BMT. The percentage of T lymphocytes from donor origin still present in the patient at the time of DLI is highly correlated with achievement of remission.