Indicators of haematopoietic recovery after bone marrow transplantation: the role of reticulocyte measurements.

The aim of this project was to study haematological recovery in patients following different types of bone marrow transplantation (BMT). Forty-three patients were analysed. The duration of haematopoietic suppression following conditioning regimens was much shorter in 12 peripheral blood stem cell transplantation patients than in 19 allogeneic BMT patients and in 12 autologous BMT patients. Among 12 different variables, the parameters with the highest specificity or predictive value for monitoring recovery in these patients were the absolute neutrophil count (ANC) at the classical cut-off point of 0.5 x 10(9)/l, an absolute reticulocyte count (RET) above 20 x 10(9)/l and a high fluorescent reticulocyte fraction (HFR) above 5%,. It is suggested that these parameters be used as the reference measurements for monitoring haematological recovery in similar studies. Among these variables, the HFR fraction was the earliest and most sensitive index of engraftment in 79.1% of patients, HFR recovery requiring a median time of 13 days after infusion, in comparison with a median period of 19 and 18 days, respectively, for RET and ANC (P<0.0001).