Early lymphocyte recovery after allogeneic hematopoietic SCT is associated with significant GVL effect in pediatric ALL but not acute myelogenous leukemia-Update study.

We earlier published data on 136 children who received hematopoietic SCT (HSCT) for ALL, and showed that early lymphocyte recovery is a powerful indicator for survival by GVL effect without increase in GVHD. To answer the question whether this is true for AML, we extended our cohort to 207 consecutive children with acute leukemia by adding 71 children with AML who received 75 HSCT's between 1994 and 2005. For the AML cohort, all patients at time of HSCT were in complete morphological remission (CR) except for one patient in CR1, who had 8% blasts in the BM before HSCT. All patients received myeloablative regimens. Stem cell sources were: matched sibling donor in 40 patients, mismatched related donor in eight patients, matched unrelated donor in 25 children and two children received cord progenitor stem cells. ALL results were published with significant P-values. In AML, absolute lymphocyte count <0.3 x 10(9)/l or >0.3 x 10(9)/l on days 21 and 30 were not predictive of relapse with a hazard ratio at day 21=0.88; P=0.8, and hazard ratio at day 30=0.5; P=0.2.