Chimerism Analysis of Children with Allogeneic Stem-Cell transplantation and Its Effect on Survival

BACKGROUND/AIMS: Allogeneic hematopoietic stem cell transplantation (Allo-HSCT) is an important and usually the only curative clinical tool for treating pediatric patients with many hereditary and acquired diseases. Although complete donor stem cell engraftment is the desired result of Allo-HSCT, patients do not always have a definite engraftment and end up with mixed chimerism. Many factors both related to patient and transplantation can affect chimerism levels. Additionally, mixed chimerism levels may affect the event free survival (EFS) differently in distinct diseases. The major goals of this study were to determine the first 100-day donor chimerism ratios and to search for a relationship between donor chimerism success (CS) (for malignant diseases, hematopoietic donor chimerism >95%; for non-malignant diseases, >70%) and EFS for pediatric patients.MATERIALS AND METHODS: We collected data from 95 pediatric patients who underwent Allo-HSCT between March, 2005 and April, 2010 at Ege University Hospital with at least one chimerism result obtained within the first 100 days.RESULTS: After checking for all other factors, CS in the first 100 days increases the chance of post-transplant EFS by-3.04 (-4.00 to-2.08) [hazard ratio (HR): 0.05 (p<0.001)]. Neutrophil engraftment was the other factor which was positively correlated with EFS (HR p-value: 0.05)CONCLUSION: There is a positive correlation between CS in the first 100 days and EFS for both malignant and non-malignant diseases.