Unrelated donor peripheral blood stem cell transplants incorporating pre-transplant in-vivo Alemtuzumab are not associated with any increased risk of significant acute or chronic GVHD

There is little information published on the long-term outcomes in recipients of T-cell depleted(TCD) unrelated donor (UD) transplants comparing Peripheral Blood Stem Cells (PBSC) with Bone Marrow (BM). We present retrospective outcome data on 306 recipients of myeloablative, HLA-matched UD allografts using pre-transplant in-vivo Alemtuzumab. Transplants were performed between 2000-2007 for CML (CP1) and acute leukaemia (CR1/2) and 184 patients received BM and 122 PBSC. The median age was 28.9 years (<1-58years) and the median follow-up was 48 months. Overall survival at 8 years is 53%. The incidence of acute GvHD was significantly higher in PBSC (65%) than BM recipients (49%; p=0.012). This represented only grade 1 GVHD with no difference in grade II-IV aGvHD (BM 23% PBSC 24%). The incidence of chronic GvHD, either overall (BM 47%, PBSC 49%) or extensive (BM 15%, PBSC 13%) was not increased with PBSC. The incidence of relapse, non-relapse mortality and survival were not significantly different. Whilst accepting the limitations of retrospective analyses, we suggest the increased risk of GvHD in recipients of PBSC in T-replete transplants is offset by in-vivo Alemtuzumab, and that either stem cell source can be used with good outcomes in this setting.