Ideal or actual body weight to calculate CD34+cell doses for autologous hematopoietic stem cell transplantation?

The number of CD34 + cells infused influences the speed of hematologic recovery post-transplant. There are limited data on whether ideal (IBW) or actual (ABW) body weight should be used to calculate CD34 + cell dose. We compared the correlation between recovery to 0.5 x 10(9)/l neutrophils and the CD34 + cell dose based upon ABW as well as IBW in 87 patients autografted for cancer. ABW was greater than or equal to25% over IBW in 43% of patients. The median number of CD34 + cells administered was 3.6 x 10(6)/kg ABW and 4.2 x 10(6)/kg IBW. The time to neutrophil recovery was 8-15 days (median 10). There was a stronger inverse correlation between CD34 + cell dose/IBW and neutrophil recovery (r(2) = 0.308; P < 0.0001) than between CD34 + cell dose/ABW and neutrophil recovery (r(2) =0.267; P<0.0001). The median time to neutrophil recovery was comparable for those receiving greater than or equal to 2 x 10(6)/kg CD34+ cells/kg IBW as well as ABW (10 days) and those receiving greater than or equal to2x 10(6)/kg CD34+ cells/kg IBW but <2/kg ABW (10 days), but was significantly slower for those receiving <2x 10(6)/kg CD34+ cells/kg IBW (12 days). These data show that the CD34+ cell dose based on IBW is a better predictor of neutrophil recovery after autotransplantation.