Reducing allogenic blood exposure in paediatric cellular therapy collections: A conservative prime strategy

Mononuclear cell (MNC) collection is critical for paediatric patients undergoing cellular therapies such as chimeric antigen receptor T-cell and haematopoietic stem cell transplantation. In children, extracorporeal volume (ECV) often exceeds 15% of total blood volume (TBV), traditionally necessitating red blood cell (RBC) priming to reduce the risk of haemodynamic instability. However, RBC priming introduces allogenic blood exposure and related complications. This study evaluated the safety and feasibility of unprimed MNC collection in paediatric patients with ECV/TBV ratios greater than 15%.

We retrospectively reviewed two paediatric patients with B-cell acute lymphoblastic leukaemia (B-ALL) who underwent MNC collection using the Spectra Optia system in continuous mononuclear cell collection mode. Both patients had ECV/TBV ratios of 16% and 17%, respectively. Vital signs and laboratory parameters were monitored throughout and after the procedures to assess for adverse events, haemodynamic instability, and need for transfusion.

Both patients completed MNC collection without adverse reactions, interruptions, or clinically significant changes in vital signs. Post-procedural haemoglobin and platelet counts showed no major declines, and neither patient required transfusion. Collection efficiency met institutional standards, and no symptoms of hypovolemia or citrate toxicity were observed.

Unprimed MNC collection can be safely performed in paediatric patients even when the ECV/TBV ratio exceeds 15%. With careful monitoring and procedural planning, this conservative strategy may reduce allogenic blood exposure without compromising safety or collection efficiency.