A study using surface markers (CD14, CD163, CD68, CD32, CD64, CD200R, CD80) on synovial tissue macrophages from RA and SpA patients found that macrophages had a mixed M1-proinflammatory/M2-anti-inflammatory phenotype, with M1 predominance in RA and IL-10-expressing macrophages in SpA (28). This evidence concerns the gene IL10 and rheumatoid arthritis.