title: Interleukin-1 production by activated macrophages surrounding loosened orthopaedic implants: a potential role in osteolysis.
abstract: IL-1 producing cells at the bone-implant interface obtained during revision of loosened total joint replacements were demonstrated by immunohistochemistry on tissue sections. Other markers for the characterization of macrophages, B cells, T cell subpopulations, IL-2 receptor and HLA-DR antigens were also used. The 10 cases examined showed excessive metallosis within the cytoplasm of the macrophages and extracellular matrix. IL-1 beta containing cells were found in seven cases, four of which showed positive staining on more than 80% of the macrophages. A relatively similar proportion of T cells was seen in all the cases. T helper (CD4 positive) cells were always present in excess of T suppressor (CD8 positive) subtype. T cells showed no expression of detectable membrane IL-2 receptor. No B cells were found in these cases. Macrophages showed very strong immunostaining for HLA-DR. These findings indicate the possible induction of IL-1 production by activated macrophages in the interface in response to the presence of metallic wear debris. In view of the well known effect of IL-1 as a potent mediator of bone lysis, the results suggest a major role of the metal debris-containing macrophages in the process of osteolysis and subsequent implant loosening.
authors.affiliation: Department of Histopathology, Royal Free Hospital School of Medicine, Hampstead, London.
authors.forename: N
authors.initials: N
authors.lastname: al Saffar
authors.forename: P A
authors.initials: PA
authors.lastname: Revell
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005547:Foreign Bodies / Q000276:immunology / Q000473:pathology; D006684:HLA-DR Antigens / Q000032:analysis; D006801:Humans; D007150:Immunohistochemistry; D007158:Immunologic Techniques; D007375:Interleukin-1 / Q000096:biosynthesis*; D007595:Joint Prosthesis / Q000009:adverse effects*; D007596:Joints / Q000473:pathology; D008262:Macrophage Activation; D008264:Macrophages / Q000378:metabolism* / Q000502:physiology; D008297:Male; D008875:Middle Aged; D010014:Osteolysis / Q000209:etiology*; D011475:Prosthesis Failure; D013194:Staining and Labeling; D016176:T-Lymphocyte Subsets / Q000473:pathology
chemical_list: D006684:HLA-DR Antigens; D007375:Interleukin-1