CXCL13 and rheumatoid arthritis: Additionally, in the synovial grafts of mice producing anti-citrullinated histones/NETs we observed significantly higher levels of CXCL13, CXCR5 and lymphotoxin (LT)β mRNA, which are master regulators of ectopic lymphoid neogenesis29 and are selectively upregulated in ELS+RA synovium10, 30 (figure 6E).