Leukemia burden delays lymphocyte and platelet recovery after allo-SCT for AML

Lymphocyte and platelet recovery may influence outcomes of allo-SCT for treatment of AML. It is not clear, however, if this impact is independent of patient and transplant characteristics. To investigate this question, we evaluated the influence of pre- or post transplant factors on day +30 absolute lymphocyte count (ALC) and the speed of platelet engraftment. We studied 106 AML patients treated with fludarabine and melphalan reduced-intensity conditioning and allo-SCT. Twenty nine percent of patients were in CR at the initiation of the conditioning, 39% had active disease with circulating blasts and 32% had active disease without circulating blasts. The graft source was peripheral blood from a matched sibling donor in 55% and BM from a matched unrelated donor in 45%. Our data showed that the presence of circulating blasts before transplantation is significantly correlated with low post-SCT day +30 ALC and slow platelet engraftment. This finding suggests that the impact of early ALC and platelet recovery on transplant outcome may not be independent of disease status at transplantation. Bone Marrow Transplantation (2009) 43, 685-692; doi:10.1038/bmt.2008.376; published online 17 November 2008