TNF and susceptibility to pneumonia measurement: An increased risk of RTI is one limitation of TNF antagonist therapy.3,11–13 Due to their systemic immunosuppressive mode of action, patients exposed to these agents have an increased risk of URTI and LRTI, serious RTIs, and pneumonia-related mortality.3,11–13 It is difficult to make an indirect comparison of the absolute rates of URTI and LRTI events observed in this analysis with those from pivotal trials of TNF antagonists in IBD [Supplementary Table 4] for several reasons.