1. ¹Department of Clinical Apheresis, Scottish National Blood Transfusion Service, Glasgow Royal Infirmary, Scotland, UK
2. ²Bone Marrow Transplant Unit, Glasgow Royal Infirmary, Scotland, UK

Correspondence: Dr PS Maclean, Department of Clinical Apheresis, Scottish National Blood Transfusion Service, Glasgow Royal Infirmary, 84 Castle Street, Glasgow, G4 0SF, Scotland, UK. E-mail: petermaclean@nhs.net

Received 1 February 2007; Revised 18 June 2007; Accepted 18 June 2007; Published online 23 July 2007.

Abstract

Stem cell dose is important in determining rate of engraftment following autograft. We show closer correlation with haematopoietic reconstitution when the CD34+ cell dose is calculated using ideal (IBW) rather than actual (ABW) body weight in 218 patients receiving peripheral blood stem cell (PBSC) autograft for haematological malignancy. ABW was 21% greater than IBW thus the median CD34+ dose of 5.0 10⁶/kg (ABW) rose to 6.1 10⁶/kg when calculated by IBW. Neutrophils reached 0.5 10⁹/l in 11 days (range 8–21), while platelets reached 20 10⁹/l unsupported in 12 days (range 7–38). For both neutrophil and platelet engraftment, a greater inverse correlation was seen when IBW was used to calculate stem cell dose (r²=0.082 vs r²=0.104 for neutrophils and r²=0.085 vs r²=0.135 for platelets). Those non-myeloma patients who failed to achieve a CD34+ dose of 4 10⁶ cells/kg by ABW but did so by IBW achieved neutrophil and platelet engraftment not significantly different from those who achieved that stem cell dose by both methods. This was not confirmed in patients treated for myeloma, possibly owing to inaccurate IBW in patients with skeletal height loss. We confirm that calculation of CD34+ cell dose by IBW safely predicts engraftment for patients with haematological malignancies other than myeloma undergoing PBSC autograft.