TNF and rheumatoid arthritis: In a study evaluating the incidence of serious infections in tumor necrosis factor (TNF)-inhibitor (TNFi) initiators from the Consortium of Rheumatology Researchers of North America (Corrona) RA registry, the overall rate of serious infections was 6–7 per 100 person-years (PY), and pneumonia was the most frequently reported infection (together with cellulitis and skin infections and urinary tract infections) [6].