OBJECTIVE: To study the allograft antigenicity of human ear cartilage and the effect of the cell extraction on antigenicity. METHODS: The human ear cartilage was acellular by cell extraction with Triton X-100. Then the cartilage and the acellular cartilage were analyzed by anti-MHC-I immunohistochemical staining, the reaction of the peripheral blood mononuclear(PBM) cells to the cartilage and the acellular cartilage and the migration of the PBM cells toward the cartilage and the acellular cartilage. RESULTS: The result of human ear cartilage was positive for the anti-MHC-I immunohistochemical staining, whereas that of the acellular cartilage was negative for the staining. The reactive proliferation of the PBM cells was more when they were co-cultured with human ear cartilage than that when they were cultured alone in vitro(P lt; 0.05), but the acellular cartilage did not show the same phenomena (P gt; 0.05); when the cartilage and the acellular cartilage were co-cultured with the PBM cells, the PBM cells migrated to the cartilage much more than that to acellular cartilage(P lt; 0.01). CONCLUSION: Human ear cartilage has allograft antigenicity and its antigenicity can be removed by cell extraction with Triton X-100.