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 alle rgic disease who developed an aseptic intolerance reaction to a chromium-co balt alloy, with local discomfort, loosening, and absence of fracture heali ng. Both in vivo and in vitro allergoimmunologic diagnostic tests were perf ormed. Methods: Patch testing was done with a European standard series. Specific s erum IgE was measured by CAP-FEIA. In addition to immunohistology (APAAP me thod), peri-implantar tissue was further analyzed by PCR to determine T-cel l-receptor-gamma rearrangement and thus the potential clonal (antigen-drive n) 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 in filtrate. The latter, instead of being random, showed an oligoclonal T-cell receptor rearrangement. In addition, there was TH1-type mediator expressio n (IL-6 and IFN-gamma, but not IL-4). Conclusions: Skin test, examination of peri-implantar tissue, and the promp t healing after replacement of the osteosynthesis material suggest an aller gic reaction. PCR analysis of peri-implantar tissue can further help to ide ntify and understand allergy-mediated implant intolerance reactions.