One recent study has focused on the spatial distribution and functional states of macrophages in RA and OA.131 Using scRNA-seq coupled with spatial transcriptomics, researchers identified three distinct macrophage clusters: M0-like MARCO+ Mφ1, M2-like CSF1R+ Mφ2, and M1-like PLAUR+ Mφ3. Here, MARCO is linked to rheumatoid arthritis.