Immune response to nonspecific and altered tissue antigens in soft tissue allografts

Soft tissue allografts have many uses in orthopaedic surgery, including knee ligament reconstruction, hand tendon surgery, shoulder instability, and rotator cuff reconstruction. The predictable biologic incorporation of soft tissue allografts without rejection or fear of disease transmission continues to be a goal of basic science researchers. A review of the current knowledge of the immune system response to donor specific, nonspecific, and altered tissue antigens in soft tissue or tendon allografts is presented. An in vitro study was done in an attempt to decrease immunogenicity of a frozen bone- ligament graft by adding irrigation with Betadine scrub solution and hydrogen peroxide to the conventional storage process of freezing. Although the irrigation with cytotoxic agents would undoubtedly further decrease immunogenicity, it also decreased stiffness and maximum load by 15%. Whether this decreased strength and stiffness would compromise the incorporation and long term success of soft tissue allografts would need to be studied by in vivo experiments.