As demonstrated by a representative sample, CD11b+CD33+HLA-DRlo/-CD14−CD15+ granulocytic MDSC-like cells were the predominant cell type in RA SF, but a small population of the CD11b+CD33+HLA-DRlo/-CD14+CD15− monocytic subset was also present (Figure 1A). Here, CD33 is linked to rheumatoid arthritis.