Transplantation of stem cells that are T-cell depleted using Campath 1H incubation following non-myeloablative (NM-alloSCT) conditioning leads to durable donor engraftment with minimal GVHD using HLA-identical family sibling and unrelated donors. The high levels of donor chimerism allow the subsequent use of DLI to treat residual disease (

Exp. Hematol.
2003
;
31
:
865
–872
). Patients with chemotherapy-refractory chronic lymphocytic leukemia (CLL) have a short life expectancy. We analyzed 12 patients with advanced CLL (9), PLL (1) or M. Waldenstrom (2) treated with NM-alloSCT. Median age was 56 years. Recipient conditioning consisted of fludarabine (30 mg/m2, 6 days), ATG (10 mg/kg, 4 days) and busulphan (3.2 mg/kg, 2 days). High numbers of G-CSF mobilized peripheral blood CD34+ cells from 11 related and 1 unrelated donors were collected (median 12 x 106/kg). The graft was T-cell depleted by 30 minutes incubation with 20 mg Campath 1H. No post-transplant GVHD prophylaxis was administered. The transplant procedure was very well tolerated. All patients engrafted rapidly. Only 1 patient experienced GVHD gr I (skin) after alloSCT. Sequential chimerism studies of bone marrow showed sustained mixed chimerism with a median donor percentage at 3 months after alloSCT of 86% (range 8–100%). At a fixed time period of 6 months after NM-alloSCT, low dose DLI was administered (5 x 106 CD3+ cells/kg) in 8 patients (3 pts too early after alloSCT and one pt died before DLI). The disease status pre-DLI was persistent disease in 4 pts and CR in 4 pts. After DLI, four patients experienced severe aGVHD (≥ grade 2) and 1 limited cGVHD. Importantly, the observed GVHD after low dose DLI was well managable. One patient received a second transplant from the original donor after myeloablative conditioning due to progressive disease with concommitant decreasing mixed chimerism. Donor chimerism increased after DLI with a median donor percentage of 98% (range, 3–100%) at 3 months after DLI. Presently at a median follow-up of 423 (range 46–1572) days, 9 patients are alive. Four patients are in complete remission, 3 with partial remission and 2 with progressive disease. Three patients have died, two due to infection and one by unknown cause.

In conclusion, in-vitro T-cell depleted NM-alloSCT followed by low dose DLI is a well tolerated strategy in older patients with advanced CLL. The low incidence of GVHD and the high levels of donor chimerism after NM-alloSCT allow the use of DLI to treat residual CLL. Our results demonstrate a profound GVL effect in patients with advanced CLL. NM-alloSCT may prolong survival for this group of patients.

Topics:
alemtuzumab, brachial plexus neuritis, busulfan, cd34 antigens, chemotherapy regimen, chronic b-cell leukemias, chronic lymphocytic leukemia, complete remission, donors, fludarabine

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2005, The American Society of Hematology
2005
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