Blood Transfusion Research Today is a free monthly online journal that collates and summarizes the latest research about Blood Transfusion, including details on blood donation, blood types, leukemia.

The impact of chimerism patterns and predonor leukocyte infusion lymphopenia on survival following T cell-depleted reduced intensity conditioned transplants.

Shaw BE, Byrne JL, Das-Gupta E, Carter GI, Russell NH

Department of Haematology, Nottingham City Hospital Campus, Nottingham University Hospitals, Nottingham UK. bshaw@doctors.org.uk

Donor leukocyte infusions (DLI) are frequently required following reduced intensity conditioned (RIC) allografts to convert mixed chimerism (MC) to full donor chimerism (FDC). The rationale is to break tolerance and maximize the graft-versus-leukemia responses. We analyzed the impact of chimerism in 125 recipients of RIC (Alemtuzumab containing) transplants. Four patterns of chimerism were seen: (1) always 100% donor chimerism (54%), (2) persisting MC (22%), (3) MC with subsequent development of FDC (18%), (4) lost donor chimerism (6%). Forty-five (36%) patients received DLI. Chimerism patterns and pre-DLI lymphocyte counts (pDLI[Ly]) were significantly associated with DLI responsiveness. Complete disease responses were seen in 6 of 17 (35%) group A patients, 9 of 10 (90%) group C patients, and 0 of 6 group B patients (P = .027), supporting reports that chimerism response is a surrogate marker for disease response. In those with MC, pDLI(Ly) were significantly lower in DLI responsive than nonresponsive patients (P = .044). At 2 years, group C patients had a significant survival advantage (P = .009) compared to all other groups. In conclusion, the chimerism pattern was the best indicator of improved survival in this cohort (ie, MC later converting to FDC). In those with MC, response to DLI therapy was associated with a low lymphocyte count pre-DLI.

Published 23 April 2007 in Biol Blood Marrow Transplant, 13(5): 550-9.
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