ANXA5 and rheumatoid arthritis: We further examined the exposure of phosphatidylserine in RA SF mpICs using Annexin-V conjugated to 4 nm gold nanoparticles and identified immunoglobulin containing ICs using larger gold nanoparticles (10 nm) conjugated to protein A. Using this method, we identify macromolecular structures up to 2 μm in diameter that contain both ICs and MPs (mpICs).