Autologous Hematopoietic Stem Cell Transplantation Without Cryopreservation: A Practical Option in Resource-Limited Settings

Letter to the Editor Autologous hematopoietic stem cell transplantation (auto-HSCT) is an established therapy for multiple myeloma (MM), Hodgkin lymphoma (HL), and non-Hodgkin lymphoma (NHL).Conventional transplantation generally requires cryopreservation, usually with dimethyl sulfoxide (DMSO), which may be challenging in resource-limited settings because of infrastructure, equipment, monitoring, and cost.Non-cryopreserved transplantation, using peripheral blood stem cells (PBSCs) maintained at 4°C before reinfusion, may provide a practical option when collection, conditioning, and reinfusion are precisely coordinated.Recent evidence supports this approach, particularly in MM.An EBMT matched analysis found similar engraftment and day-100 non-relapse mortality between non-cryopreserved and cryopreserved MM transplants; 3-year overall survival was 81% versus 82%, respectively [1].A recent Turkish study likewise reported comparable engraftment and clinical outcomes [2].In Thailand, a 58-patient series comprising 40 MM and 18 lymphoma patients reported CD34+ viability before infusion of 99.1% and 97.1%, respectively, with median neutrophil/platelet recovery of 9/11 days in MM and 13/14 days in lymphoma [3].The Moroccan experience provides particularly relevant evidence.In a prospective series of 64 MM patients, PBSCs were mobilized with G-CSF for 4-5 days, collected by leukapheresis, stored at 4°C for 48-72 hours, and reinfused after melphalan 200 mg/m².The mean graft dose was 12.97 × 10⁶ CD34+/kg; median neutrophil and platelet recovery occurred on days 13 and 11, respectively, with no graft reinfusion failure.Day-100 treatmentrelated mortality was 4.68%; at 24 months, overall and progression-free survival were 83.5% and 65.9%, respectively [4].For MM, published experience generally supports refrigerated storage for approximately 24-72 hours.In lymphoma, a matched analysis of 94 patients, including 66 with HL, demonstrated feasibility with PBSCs stored at 4°C for up to 6 days, although cryopreserved grafts produced faster engraftment [5].Thus, lymphoma should not be considered an absolute contraindication, but cryopreservation remains preferable when timing is uncertain.Mobilization should follow a validated disease-specific protocol, using G-CSF alone or chemomobilization as appropriate.DMSO is unnecessary for fresh PBSC storage at 4°C.In contemporary MM, single planned ASCT is often sufficient, reducing the need for prolonged graft storage.Non-cryopreserved auto-HSCT should therefore be considered a feasible, potentially less resource-intensive option, rather than a universal replacement, for carefully selected patients in validated, well-coordinated programs.Its feasibility depends on a highly predictable interval between stem-cell collection and reinfusion, with adequate CD34+ collection, validated temperature monitoring, predictable conditioning, and timely reinfusion.An inherent limitation is the inability to maintain a cryopreserved backup graft for future use; unexpected delays may also compromise graft quality.