Bone transplantation and immune response

Bone is the second most common transplant tissue after blood, with the iliac crest autologous graft being most used. Bone transplantation induces osteogenesis to repair bone defects. Despite being the most efficient, autogenous bone requires an additional incision and its supply may be inadequate. Deepfrozen allogeneic bone can be an alternative, but is at risk of microbiological contamination, transmission of unrecognised germs, delayed incorporation, and cellular and humoral immune reactions. Synthetic graft substitutes combine scaffolding properties with biological elements to stimulate cell proliferation and differentiation and eventually osteogenesis. However, they generally lack osteoinductive or osteogenic properties and have various effects on bone healing. We present an overview of bone grafts and graft substitutes in clinical use, and the immune responses to allogeneic bone.