%0 Journal Article
%T Intimal lining layer macrophages but not synovial sublining macrophages display an IL-10 polarized-like phenotype in chronic synovitis
%A Carmen A Ambarus
%A Troy Noordenbos
%A Maria JH de Hair
%A Paul P Tak
%A Dominique LP Baeten
%J Arthritis Research & Therapy
%D 2012
%I BioMed Central
%R 10.1186/ar3796
%X Expression of polarization markers on synovial macrophages, peripheral blood monocytes, and in vitro polarized monocyte-derived macrophages from SpA versus RA patients was assessed by immunohistochemistry and flow cytometry, respectively. The polarization status of the intimal lining layer and the synovial sublining macrophages was assessed by double immunofluorescence staining.The expression of the IL-10 polarization marker cluster of differentiation 163 (CD163) was increased in SpA compared with RA intimal lining layer, but no differences were found in other M1 and M2 markers between the diseases. Furthermore, no significant phenotypic differences in monocytes and in vitro polarized monocyte-derived macrophages were seen between SpA, RA, and healthy controls, indicating that the differential CD163 expression does not reflect a preferential M2 polarization in SpA. More detailed analysis of intimal lining layer macrophages revealed a strong co-expression of the IL-10 polarization markers CD163 and cluster of differentiation 32 (CD32) but not any of the other markers in both SpA and RA. In contrast, synovial sublining macrophages had a more heterogeneous phenotype, with a majority of cells co-expressing M1 and M2 markers.The intimal lining layer but not synovial sublining macrophages display an IL-10 polarized-like phenotype, with increased CD163 expression in SpA versus RA synovitis. These differences in the distribution of the polarized macrophage subset may contribute to the outcome of chronic synovitis.The normal synovial membrane consists of two distinct structures: the intimal lining layer and the synovial sublining. The normal intimal lining layer comprises fibroblast-like synoviocytes and intimal lining layer macrophages, whereas the synovial sublining consists of connective tissue containing blood vessels, fibroblasts, adipocytes, and a limited number of resident immune cells, such as macrophages and mast cells [1]. Chronic inflammatory arthritis is histolog
%U http://arthritis-research.com/content/14/2/R74