Leukocyte-derived microparticles from RA patients induce proteolytic enzymes, such as matrix metalloproteinase 1 (MMP1), MMP3, MMP9, and MMP13, and pro-inflammatory cytokines, such as IL-6, IL-8, MCP-1, and MCP-2, via stimulation of synovial fibroblasts [17]. Here, MMP1 is linked to rheumatoid arthritis.