There is a critical shortage of investigators in health care who are prepared to combine clinical expertise with research inquiry that will advance the health and treatment of diseases affecting children, in particular those with hematological disorders and those with a variety of diseases who require transfusion and/or novel cell-based therapies. This renewal application will continue our highly collaborate multidisciplinary, interinstitutional program which couples transformative mentored research experiences with didactic education and career development in basic, translational, and clinical research in four content areas of importance to the National Heart, Lung and Blood Institute (NHLBI) with an emphasis on transfusion medicine, cell-based therapies, vascular biology and inflammation. Over two to three years, five postdoctoral trainees who are completing fellowships in hematology- oncology, allergy-immunology, cardiology, critical care medicine, neonatology, pulmonology or similar pediatric subspecialty fields will submit competitive applications to this program. If selected, they will be engaged in learning cutting edge techniques including molecular, genetic, cellular, device and community-based research methods using a multidisciplinary training program with 26 preceptors from Children's National (CNH), its Research Institute (CNRI), The George Washington University (GWU), and the intramural programs of the NIH. Acquisition of skills in cell therapy and transfusion medicine will include the principles of Good Manufacturing Practice (GMP), gene editing and cell/tissue expansion/engineering. These laboratory-based experiences will be coupled with formal training in hypothesis building, data analytics, biostatistics, grant preparation, communication and writing skills in many cases leading to a Master's degree. Leveraging existing collaborations, we will prepare pediatric trainees from diverse subspeciality backgrounds who will ultimately lead research teams, compete successfully for grant support, and become the next generation of pediatric researchers focused on the pathogenesis and pathobiology of disorders affecting children requiring blood and cell-based therapies and who will create and implement new treatment paradigms and oversee the clinical management of hematologic, cardiovascular, pulmonary and inflammatory disorders.