Detection of antibodies against corrosion products in patients after Co-Cr total joint replacements.

Sensitivity to nickel, cobalt, and chromium is common among the general population. The identification of these sensitivities is generally by the detection of cell-mediated immunity. Detection of humoral immunity to these metals has rarely been undertaken because suitable assays are not available. To further our knowledge about the systemic humoral immune system response to weak hapten-syngeneic or allogeneic protein conjugates (corrosion and wear products of metallic orthopedic devices), a sensitive enzyme-linked immunosorbent assay (ELISA) method for testing for antibody (humoral immunity) to metals was developed. Microtiter plates were coated with human serum albumin (HSA) or glutathione (GSH) and then conjugated with metal ions. Plates coated with HSA or GSH and without metal ions served as background controls. An indirect ELISA method was used to detect antibody binding. Patients bearing cobalt-chromium alloy devices were considered to be the most likely candidates as sources of antibody to metal and were used to document the usefulness of the test. Specificity of the test was documented by inhibition studies with these metal ions in the ELISA assay. The serum samples of 10 patients were screened for the presence of Cr-, Co-, or Ni-specific antibody at various periods up to 5.5 years after implantation of F-75 cobalt alloy total joint replacements. All patients had implants that were functioning well. The pre- and postimplantation humoral immune profiles of patients were determined and compared with each preimplantation control and with a pooled normal serum sample. This study presents evidence that metal-protein complex-specific antibodies can be detected. The clinical implications remain to be determined.