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Advances in Allogeneic Hematopoietic Stem Cell Transplants in the Pediatric Population BY STEVEN KUERBITZ, MD HEMATOPOIETIC STEM CELL TR ANS' PL A NTATION (HSCT) has become an accepted and potentially curative therapy for many life-threatening cancers and nonmalignant disorders. Although the approach is not without serious risks, adva nces in tra nspla nts have led to improved patient outcomes, especially in the pediatric population. AUTOLOGOUS VERSUS ALLOGENEIC HSCT According to the U.S. Depa r tment of Hea lt h a nd Huma n Ser v ices, of t he nearly 20,000 bone marrow or umbili- cal cord blood transplants in the United States in 2014, 11,392 were autologous, whi le 3,54 4 were related a l logeneic and 4,926 unrelated a llogeneic. They report that transplant procedures are continuing to increase. Of the proce- dures performed in 2016, 19% involved children ages 0 to 18. A necdota lly at Akron Children's Hospital, we have per- formed 112 HSCTs since the procedure became available in 2000. Aut ologous st em cel l t ra n spla nt s (autoHSCT), in which the stem cell graft is derived from the patient 's own bone marrow or periphera l blood, are most of ten indicated for treatment of solid tumors such as lymphoma, sarcoma, neu- roblastoma and brain tumors. Allogeneic stem cell tra nspla nts (a lloHSCT), in which the graft is donated by a di€er- ent related or unrelated individua l, are genera lly performed for treatment of leu kem ia , ly mphoma , i m mune def i- ciency syndromes, metabolic disorders, hemoglobinopathies, myelodysplastic syndromes, autoimmune disorders and bone marrow failure. Because allogeneic stem cells almost always come from a genetically nonidenti- ca l donor, a lloHSCT carries a greater risk of some complications, including Graft-versus-Host Disease (GvHD). A blood relative is the preferred donor, as he or she has the greatest likelihood of a close human leukocyte antigen (HLA) match. For full siblings, the likelihood of an HLA match is about 25%. MAKING BETTER MATCHES When a sibling is not available, a lter- native donor options might include a parent (genera lly a 50% match) or an HLA-matched, unrelated individual iden- tified from a registry of volunteer donors. Continued advancement in techniques for genetic matching of unrelated grafts has facilitated improved outcomes so that results of related versus unrelated tra nspla nts a re compa rable. Equa lly important, treatments for GvHD and other transplant-related complications have a lso improved. That 's not to say there's no room for improvement. For exa mple, the donor registr y includes far more donors of European descent, making it more challenging to find suit- able matches for African-Americans and other ethnic minorities. Increasing the numbers of underrepresented popula- tions is a major goal for the registry. TREATMENT CONSIDERATIONS FOR CHILDREN Patients t y pica l ly spend four to si x weeks in the hospital after infusion of the stem cell graft. Close observation is necessary to identify complications such as infection, mucositis, ma lnu- trition, organ dysfunction and GvHD. Infection remains a relatively common problem in hematopoietic stem cel l transplant patients due to the disrup- tion of mucosa l barriers, such as skin and intestinal mucosal, and because of the immunosuppressive medications necessary to facilitate engraftment and prevent GvHD. To reduce infection risk during engraftment, stem cell transplant units are designed for maximum sterility. We've a lso found it 's impor ta nt to address the child's emotiona l, socia l and physical comfort in addition to their medical care. FUTURE AREAS OF STUDY Research around hematopoietic stem cell transplantation is active and varied, focusing on objectives from the identifica- tion of biomarkers predictive for GvHD to augmenting the antitumor activity of the transplanted cells. As HSCT is explored for treatment of new disease categories, such as autoimmune disease, while novel non-transplant therapies are developed for high-risk diseases such as leukemia, the field of hematopoietic stem cell transplantation continues to evolve in an exciting way. Dr. Steven Kuerbitz is director of Stem Cell Transplantation and D ivisional Research at Akron Children's Hospital's Center for Childhood Cancer and Blood D i s o rd e rs . He i s b oa rd ce r t if i ed in Pediatrics and Pediatric Hematology/ Oncology. ■ 1 4❱❱❱❱❱ S P E C I A L C L I N I C A L S E C T I O N : C A N C E R