Graft CD34+ Cell Dosing Adjustment Based on Body Surface Area As a Better Predictor of Hematopoietic Engraftment
Authors: An Seungwon , Park Youngmin , Mora Celeste , Uzoka Chukwuemeka , Sanchez Matias , Zucchetti Elisa , Sweiss Karen , Campbell Lee Sally , Rondelli Damiano , Mahmud Nadim 
Published: December 2024

This retrospective study compares the effects of body weight-based CD34+ cell dosing with body surface area (BSA) and body mass index (BMI) on the predictability of neutrophil and platelet engraftment after autologous stem cell transplantation (SCT) in multiple myeloma (MM) patients.
MM patients (autologous donors, n = 97; 48 males and 49 females) were categorized into two groups based on BMI (&lt;25 and &gt;25) and BSA (&lt;1.9 m² and &gt;1.9 m²). The average age for males was 64.50 ± 9.13 years and for females was 64.89 ± 8.72 years (no statistical significance). Time to hematopoietic engraftment was compared between BMI and BSA groups to establish their correlation with the recovery of neutrophils and platelets following SCT.
Time to neutrophil engraftment following autologous SCT was 11.14 ± 0.56 days for patients with BMI greater than 25 (n = 22), while it was 11.1 ± 0.80 days for patients with BMI lower than 25 (n = 75). Thus, neutrophil engraftment time displayed no significant difference between the normal (BMI &lt; 25) and overweight (BMI &gt; 25) groups. Time to platelet engraftment following SCT was 17.05 ± 5.13 days for the high BMI group and 17.79 ± 4.76 days for the low BMI group. There was no statistical significance in neutrophil and platelet engraftment between the two BMI groups (high and low). On average, patients with a BSA lower than 1.9 m² (n = 40) had a BMI of 26.61 ± 5.55, while those with a BSA greater than 1.9 m² (n = 57) had a BMI of 32.09 ± 6.36 (p ≤ 0.001). There was no statistically significant difference in neutrophil engraftment between the higher and lower BSA groups. However, the higher BSA group (&gt;1.9 m²) required a significantly longer time for platelet engraftment 18.55 ± 4.71 days compared to 16.28 ± 4.75 days (p ≤ 0.05) in patients with a BSA less than 1.9 m², following SCT despite receiving comparable CD34+ cells/kg body weight. The CD34+ cells/kg (× 10⁶ per kg of body weight) administered to the two groups, one with a body surface area (BSA) greater than 1.9 m² and the other with a BSA less than 1.9 m², were comparable (7.06 ± 4 vs. 6.66 ± 3.65, no statistical significance). However, when the dose of CD34+ cells infused was calculated based on BSA, patients with a BSA greater than 1.9 m² received a significantly higher dose of CD34+ cells (× 10⁸/m²) (6.07 ± 3.31 vs. 4.78 ± 2.60 in the low BSA group, p &lt; 0.05). Notably, there was a significant delay in platelet engraftment following SCT in male patients with a BSA greater than 1.9 m², compared to those with a lower BSA (19.59 ± 4.9 days vs. 15.47 ± 5.79 days, p &lt; 0.05), despite both groups receiving comparable CD34+ cells per kg of body weight. When CD34+ cells infused were compared as CD34+ cells/kg, CD34/m² BSA, and CD34/BMI unit, there was no statistically significant difference, except for a delay in neutrophil engraftment in males (11.3 ± 0.75 days) compared to female patients (10.89 ± 0.7 days, p ≤ 0.01). Within high BSA group 51% were African American while 39% were non-Hispanic White and remaining 10% were Asian or others.
Reducing the time to hematopoietic engraftment following SCT can not only reduce the duration of hospital stay but also have a potentially significant clinical impact by reducing infection, bleeding, and transfusion-related complications. Our current study implies the necessity of adjusting the CD34+ cell dose to be infused based on body weight (kg) in accordance with BSA, especially for donors with higher BSA (&gt;1.9 m²). The observed delay in platelet engraftment with BSA greater than 1.9 m², who are also obese (BMI 32.09) males, and the delay in neutrophil engraftment in males, independent of BSA or BMI, despite comparable CD34+ cell doses (kg body weight) infused, highlight the significance of implementing personalized dosing strategies.