Despite their inhomogeneous distribution patterns, we observed a moderate to high correlation of total CD68-, CD3- and CD55- staining in the entire sublining (i.e. not partitioned into different layers) and the synovitis score and its components, which has been established as a valuable tool to assess synovitis activity and to discriminate between low- and high-grade synovitis [17]. This evidence concerns the gene CD68 and synovitis.