Supplementary Figure 9: Multicolor immunofluorescent staining of paraffin synovial tissue from target RA and OA patient samples.

We performed multi-color immunofluorescence images to validate the unique cellular and molecular signatures revealed by the scRNA-seq analysis and show the contrasting cellular and molecular features of the microenvironment in the inflamed RA and OA synovia. a, Numerous CD14⁺IL-1β⁺ colocalization in inflamed RA synovium tissue (denoted by white box). b, Very few CD14⁺IL-1β⁺ cells in the OA synovium. c, Numerous CD3⁺CD8⁺IFNγ⁺ T cells in RA biopsy (denoted by white box). d, Low numbers of CD3⁺CD8⁺IFNγ⁺ T cells in the synovium of OA. e, An increased number of CD20⁺T-bet⁺CD11c⁺ B cells in the inflamed RA synovium (denoted by white box). f, Very scared B cells and specially T-bet⁺CD20⁺ B cells in synovial tissues of OA. Globally, we found enrichment for the populations of interest in the biopsies of RA inflamed synovium, compared to specific populations in OA synovia. Images were acquired at ×200 magnification. Scale bar, 100 μm.