Development of a validated blood test for nickel sensitization

摘要

Of the 1 million hip and knee replacements that are performed annually in the United States, 7.5% to 10% will fail and require revision (www.AAOS.org). As the number of implants is expected to exceed 2 million by 2015, the number of joint failures is also expected to rise. Immunologic sensitization to implant metals is one of the causes of implant failure, along with infection and biomechanical mismatch, and distinct from metallosis caused by metal wear particles. Metal sensitization has only recently been recognized as a cause of joint failure; the delay in recognition is in part due to the lack of convenient, standardized, and validated laboratory tests for sensitization. It is a delayed type IV hypersensitivity reaction, currently diagnosed by skin patch testing, that indicates that sensitized memory T cells have recognized the metal antigen-protein conjugate presented by dendritic cells in regional lymph nodes, proliferated, and then migrated to the source of the antigen.