Predictive Factors for Rapid Engraftment of Neutrophil and Platelet After Allogenic Peripheral Blood Stem Cell Transplantation in Patients with Hematologic Malignancies

CD34+ cell dose has been the most reliable measure for predicting the kinetics of hematopoietic reconstitution including rapid neutrophil and platelet engraftment in allogenic stem cell transplantation (AlloSCT). Moreover, cell phenotypes related with engraftment were reported that CD34+CD33- cells and CD34+CD41+ cells, CD26, and CD8+ cytotoxic T cells and CD56+ natural killer cells, were potential predictors of early engraftment in HCT. The purpose of our study is to investigate predictors which influence on early engraftment including cell phenotypes and clinical factors in patients with hematologic malignancy underwent AlloSCT in South Korea.

Three hundred twenty four patients who received AlloSCT from at hematopoietic stem cell transplantation centers in South Korea between September 1998 and November 2011 were analyzed in this study. Subset analyses of the peripheral blood stem cells (PBSCs) and peripheral lymphocytes were conducted by using a flow-cytometric method. Two-color (FITC; PE) flow-cytometric immunophenotyping was performed. The hematopoietic stem cell (CD34+ cells), T cells (CD3+), helper T cells (CD3+/CD4+), cytotoxic T cells (CD3+/CD8+), and NK cells (CD56+) were all analyzed on a FACScan. And other clinical factors were analyzed in this study such as age, sex, disease status before AlloSCT, cormobidity index score, intensity of conditioning regimen, donor age, donor sex, and etc. The definitions of engraftment were more than 0.5×10⁹/L and 20 ×10⁹/L after AlloSCT in neutrophil and platelet, respectively.

In univariate analysis, predictive factors for engraftment of neutrophil at least day 12 were shown complete remission (CR) state befo re AlloSCT (p-value; 0.002), donor age less than 30 years old (0.004), mononuclear cell counts (MNC) more than 7.0 × 10⁸/kg (p-value; 0.001), CD34+ cells more than 5.0 × 10⁶/kg (p-value; 0.045), CD3+ T cells more than 3.0 × 10⁸/kg (p-value; 0.002) and CD3+/CD8+ T cells more than 2.0 × 10⁸/kg (p-value; 0.012). Predictive factors for engraftment of platelet at least day 14 were female (p-value; 0.004), shown complete remission (CR) state before AlloSCT (p-value; < 0.001), donor age less than 30 years old (0.006), mononuclear cell counts (MNC) more than 7.0 × 10⁸/kg (p-value; < 0.001), CD34+ cells more than 5.0 × 10⁶/kg (p-value; 0.050), CD3+ T cells more than 3.0 × 10⁸/kg (p-value; < 0.001), CD3+/CD4+ T cells more than 3.0 × 10⁸/kg (p-value; < 0.001), CD3+/CD8+ T cells more than 2.0 × 10⁸/kg (p-value; < 0.001) and CD56+ NK cells (p-value; 0.001). In multivariate analysis, significant predictive factors for engraftment of neutrophil on day 12 was CR state before AlloSCT (RR; 0.466, 95% C.I.; 0.263 – 0.824, p-value; 0.009) and for engraftment of platelet on day 14 were female (RR; 2.230, 95% C.I.; 1.079 – 4.608, p-value; 0.030), CR state before AlloSCT (RR; 0.332, 95% C.I.; 0.165 – 0.669, p-value; 0.002), CD3+ T cells more than 3.0 × 10⁸/kg (RR; 3.649, 95% C.I.; 1.659 – 8.030, p-value; 0.001), and CD3+/CD8+ T cells more than 2.0 × 10⁸/kg (RR; 2.505, 95% C.I.; 1.123 – 5.587, p-value; 0.025).

In our study, predictive factors for engrafment of neutrophil at least day 12 was CR state before AlloSCT and engraftment of platelet at least day 14 were female, CR state before AlloSCT, CD3+ T cells more than 3.0 × 10⁸/kg and CD3+/CD8+ T cells more than 2.0 × 10⁸/kg. However, further studies are needed to determine more impressive predictive cell phenotypes and clinical factors for engraftment of neutrophil and platelet after allogenic stem cell transplantation.

No relevant conflicts of interest to declare.