MACROPHAGE REACTIONS IN SEPTIC ARTHRITIS

With the aid of monoclonal antibodies, macrophages can be split into f unctionally distinct subpopulations on the basis of their phenotype. A bsence of macrophage subtypes has been noted in chronic inflammatory p rocesses, e.g. posttraumatic osteomyelitis, rheumatoid arthritis and s arcoidosis. In the inflammatory focus of acute septic arthritis (n = 1 3 patients) however, macrophages constitute the majority of immunocomp etent cells. The inflammatory macrophage subtype 27E10 was clearly pre sent in increased numbers in 11 of 13 biopsies from the inflammatory f oci, showing the effector task of this subtype in synovial resistance. The anti-inflammatory macrophage subset RM3/1 was present in increase d numbers in biopsies of infected tissue and the surrounding soft tiss ue. The occurrence of 25F9-positive macrophages, typical of the late p hase of inflammation, varied widely in the biopsies.