RESUMO
Several attempts have been made to optimize pre-transplant risk assessment to improve hematopoietic stem cell transplantation (HSCT) decision-making and to predict outcome post- HSCT. However, its relevance to the pediatric population remains unclear. We report the results of revalidation of the HCT-CI in 874 children who received 944 HSCTs for malignant or non-malignant diseases at a single centre. After finding the HCT-CI invalid in our patient population; we proposed a modified pediatric adapted scoring system that captures risk factors (RF) and comorbidities (CoM) relevant to pediatrics. Each RF/CoM was assigned an integer weight based on its hazard ratio (HR) for TRM; 0 (HR <1.2), 1 (1.2 ≥HR <1.75), 2 (1.75 ≥HR <2.5), 3 (HR ≥2.5) .Using these weights, the pediatric adapted HSCT-RI (PARI) was devised, and patients were divided into 4 risk groups; group 1 without RF/CoM, group 2: scores 1-2, group 3: scores 3-4, group 4: scores ≥5. There was a linear increase in 2-year TRM from group 1 to 4 (TRM= 6.2% in group 1, 50.9% in group 4). PARI was successfully validated on an internal and external cohort of pediatric patients. Comparing models using c-statistics, PARI was found to be a better model than HCT-CI in predicting 2-year TRM in children with Akaike's and Schwarz's Bayesian information criteria (AIC and BIC) of 1069.245 and 1073.269; respectively using PARI vs 1223.158 and 1227.051; respectively using HCT-CI. We believe that PARI will be a valuable tool enabling better counselling and decision making for pediatric HSCT patients.
RESUMO
Epstein-Barr virus (EBV) establishes a lifelong latent infection in healthy humans, kept under immune control by cytotoxic T cells (CTLs). Following paediatric haematopoetic stem cell transplantation (HSCT), a loss of immune surveillance leads to opportunistic outgrowth of EBV-infected cells, resulting in EBV reactivation, which can ultimately progress to post-transplant lymphoproliferative disorder (PTLD). The aims of this study were to identify risk factors for EBV reactivation in children in the first 100 days post-HSCT and to assess the suitability of a previously reported mathematical model to mechanistically model EBV reactivation kinetics in this cohort. Retrospective electronic data were collected from 56 children who underwent HSCT at Great Ormond Street Hospital (GOSH) between 2005 and 2016. Using EBV viral load (VL) measurements from weekly quantitative PCR (qPCR) monitoring post-HSCT, a multivariable Cox proportional hazards (Cox-PH) model was developed to assess time to first EBV reactivation event in the first 100 days post-HSCT. Sensitivity analysis of a previously reported mathematical model was performed to identify key parameters affecting EBV VL. Cox-PH modelling revealed EBV seropositivity of the HSCT recipient and administration of anti-thymocyte globulin (ATG) pre-HSCT to be significantly associated with an increased risk of EBV reactivation in the first 100 days post-HSCT (adjusted hazard ratio (AHR) = 2.32, P = 0.02; AHR = 2.55, P = 0.04). Five parameters were found to affect EBV VL in sensitivity analysis of the previously reported mathematical model. In conclusion, we have assessed the effect of multiple covariates on EBV reactivation in the first 100 days post-HSCT in children and have identified key parameters in a previously reported mechanistic mathematical model that affect EBV VL. Future work will aim to fit this model to patient EBV VLs, develop the model to account for interindividual variability and model the effect of clinically relevant covariates such as rituximab therapy and ATG on EBV VL.