Sema3B alone, but not in combination with LPS, up-regulated the mRNA and protein expression of MerTK, and the mRNA expression of the MerTK ligand GAS6 (19–21) in both RA MØIFN-γ (Figure 4A) and RA MØM-CSF (Figure 4B), although differences were more pronounced in the latter. This evidence concerns the gene MERTK and rheumatoid arthritis.