Interleukin 15 production by macrophages in the implant interface membraneof aseptically loosened joint replacements

The T lymphocytes are cells involved in immunologically mediated hypersensi tivity reactions. They are found in the cellular infiltrate present in the interface membrane of aseptically loosened joint prostheses. Activation of these cells has been demonstrated but not the important cytokine, interleuk in 2 (IL2) required for such activation. This study describes the localizat ion of IL15 and its mRNA in macrophages in interface membranes associated w ith activated T lymphocytes which are proliferating (as is evident from HLA -DR and Ki67 expression, respectively). The findings provide further eviden ce for immune mediated processes in aseptic loosening of orthopaedic implan ts because IL15 has similar activities to IL2 in T lymphocyte activation. ( C) 1998 Kluwer Academic Publishers.