TNF and rheumatoid arthritis: TNF is a major cause of the excess inflammation that drives RA (Kalliolias and Ivashkiv 2016), and it is likely to remain the preferred target of first-line biologic therapy for the foreseeable future, as in populations with active RA despite ongoing, nonbiologic, DMARD therapy (Emery et al. 2014; Taylor and Feldmann 2009).