TNF and rheumatoid arthritis: Factors that increase the risk of infections in RA include disease-related immune dysfunction (involving T cells such as T-helper type 1 cells and, as described more recently, T-helper type 17 cells) [2] and immunosuppressive effects of drugs used to treat the disease, such as long-term glucocorticoids, disease-modifying antirheumatic drugs (DMARDs), and TNFα antagonists [3,4].