TNF and Arthritis: The keywords gradually changed from “necrosis factor alpha,” “methotrexate,” “sulfasalazine,” and “tumor necrosis factor” to “inflammation” and “psoriatic,” “arthritis,” “axial spondyloarthritis,” and “remission.” Figure 8C shows the results of an analysis performed using the CiteSpace software, showing the top 25 keywords with the strongest reference bursts.