Intolerance of osteosynthesis material:: evidence of dichromate contact allergy with concomitant oligoclonal T-cell infiltrate and TH1-type cytokine expression in the peri-implantar tissue

Background: We report on a 37-year-old man without history of previous allergic disease who developed an aseptic intolerance reaction to a chromium-cobalt alloy, with local discomfort, loosening, and absence of fracture healing. Both in vivo and in vitro allergoimmunologic diagnostic tests were performed. Methods: Patch testing was done with a European standard series. Specific serum IgE was measured by CAP-FEIA. In addition to immunohistology (APAAP method), peri-implantar tissue was further analyzed by PCR to determine T-cell-receptor-gamma rearrangement and thus the potential clonal (antigen-driven) T-cell repertoire. The actual tissue mRNA expression for IL-4, IL-6, and IFN-gamma was visualized by RT-PCR. Results: Skin testing gave a delayed-type reaction to dichromate. Specific serum IgE to natural rubber latex and grass pollen was found - but without clinical symptoms. Immunohistology revealed a monocytic and dense T-cell infiltrate. The latter, instead of being random, showed an oligoclonal T-cell receptor rearrangement. In addition, there was TH1-type mediator expression (IL-6 and IFN-gamma, but not IL-4). Conclusions: Skin test, examination of peri-implantar tissue, and the prompt healing after replacement of the osteosynthesis material suggest an allergic reaction. PCR analysis of peri-implantar tissue can further help to identify and understand allergy-mediated implant intolerance reactions.