Human iPSC-derived bone marrow organoids with integrated hematopoietic and T cell-supportive niches

• • iBMOs self-organize into three distinct compartments (stromal, vascular, hematopoietic) and yield stable iBOSS lines that express Notch-associated molecules, enabling T-lineage and dendritic cell differentiation from iPSC-derived progenitors in vitro. • • Following transplantation into immunodeficient mice, iBMOs sustain human erythropoiesis and undergo bone formation, demonstrating autonomous niche activity in vivo with measurable engraftment and differentiation. • • The platform integrates bone marrow and T cell–supportive functions in a single defined iPSC-derived model, overcoming the anatomical separation that limits conventional in vitro systems. • • iBMO–iBOSS provides a reproducible and scalable source of immune cells, with potential for patient-specific immunotherapy and regenerative medicine applications.