Patrick Crombez

Donor lymphocyte infusions in adult haploidentical transplant: a dose finding study.

Summary:Haploidentical transplantation has become a clinical option for patients lacking a compatible donor. However, patients are still referred at advanced stages and are usually heavily pretreated. This results in a high risk of toxicity, relapses and infections. We therefore started a donor lymphocyte infusion (DLI) dose-finding protocol, to try to improve both relapse rate and immunity reconstitution. In all, 12 consecutive patients were investigated. All had a refractory, some progressive, disease. Conditioning consisted of TBI, melphalan, ATG, fludarabine and CSA pretransplant. In four rapidly progressive patients, Ara-C had to be given 1 week preconditioning. The graft was T- and B-cell depleted with a fixed reinfused CD3 dose of 5×104/kg. All patients engrafted before day 20. G-CSF was given from day 5 post-transplant and replaced with GM-CSF in the last three patients. Nonrelapse related mortality was 0/12 at 1 year. DLI were started at day 28 (3×104 CD3/kg) in the two first patients. This resulted in acute graft-versus-host disease (aGVHD) and chronic graft-versus-host disease (cGVHD) in both, but they did not relapse. The next dose was 1×104/kg monthly for 3 months. This was well tolerated with only one grade I GVHD. Given the high relapse rate, we escalated doses (1, 3 and 10×104/kg). This produced GVHD in all. We next moved, to GM-CSF and 1×104 CD3/kg monthly. Overall, 6/12 patients relapsed and received therapeutic DLI, starting at 1×105 CD3/kg with escalation every 2 weeks. We conclude that prophylactic DLI are feasible in adult haploidentical transplantation, without GVHD at a monthly dose of 1×104 CD3/kg. They result in faster CD4 recovery and a low rate of infections. The impact of GM-CSF remains to be further investigated. This scheme seems ideal for patients transplanted early in the course of their disease. In very bad prognosis patients, it remains insufficient to rapidly induce a GVL effect. Escalated doses are feasible but the price is aGVHD. Therapeutic DLI can be given at higher doses, depending on the time post-transplant. Haploidentical transplantation with low-dose DLI is a safe procedure that should be considered in all patients needing a transplant, but lacking a matched donor, early in the course of the disease.

Complete remission following donor PBSC after low-dose cytarabine chemotherapy for early relapse of acute myelogenous leukemia after allogeneic stem cell transplantation

A 55-year-old woman with chemotherapy-resistant acute myeloblastic leukemia (AML M2) relapsed 3 months after allogeneic PBSC transplant. The patient was treated with two cycles of low-dose cytarabine chemotherapy followed by G-CSF mobilized donor PBSC after cessation of all immunosuppressive treatment. Hematological and cytogenetic complete remission was observed after the first cycle. The patient had been previously treated for AGVHD after allogeneic PBSC transplantation and experienced a second AGVHD after the second cycles of cytoreductive treatment and donor PBSC infusion. Hematological recovery after donor PBSC infusion was faster than recovery after previous chemotherapy or high-dose chemotherapy. During treatment no febrile neutropenia was observed. This case shows that donor PBSC infusion cannot only provide prolonged complete hematological and cytogenetic remission but also seems to support accelerated hematopoietic recovery for some patients relapsing after allogeneic BMT.