Homologous to lymphotoxins exhibiting inducible expression and competing with herpes simplex virus glycoprotein D for herpesvirus entry mediator (HVEM), a receptor expressed by T lymphocytes (LIGHT), a member of the TNF superfamily (TNFSF14), that is significantly upregulated in the serum of human rheumatoid arthritis patients, is another cytokine expressed by activated T cells as well as monocytes, granulocytes, and immature dendritic cells. The gene discussed is TNFSF14; the disease is rheumatoid arthritis.