CD19 and neoplasm: In a recent trial, the determinants of CD19 (−) relapse after tisa-cel infusion in pediatric patients and young adults were high tumor burden (occurrence of CRS), prior blinatumomab, detectable MRD at Day 28 (Sub-distribution hazard ratio (SHR) 7.2, p = 0.006), whereas CD19 + relapse correlated with loss of B-cell aplasia (BCA) (SHR 21.7, p = 0.004) [39].