Infections in patients affected by rheumatologic diseases associated to glucocorticoid use or tumor necrosis factor-alpha inhibitors

A great diversity of infectious agents can affect patients that use steroids at immunosuppressive doses or tumor necrosis factor a (TNF-alpha) antagonists. The list of participating microorganisms is more restricted in the case of anti TNF-a blockers. Overlapping agents include intracellular bacteria, Mycobacterium tuberculosis, geographic fungal agents that have the ability to establish granulamotous infections, herpes zoster, and reactivation of chronic hepatitis B virus infection. An important conceptual issue for these infections is the existence of a threshold prednisone daily dose for the emergence of opportunistic infections but higher levels of immunosuppression and cofactors are required in the case of Pneumocystis jiroveci and cytomegalovirus infections. In order to prevent these threats, a detailed medical evaluation is needed before prescription to detect potential risks and manage them properly. Prevention rules must be prescribed in every case, that include common sense behaviors, vaccines, and in selected cases, chemoprophylaxis for latent tuberculosis (TB) infection, P jiroveci pneumonia (PCP) or other specific requirements. Latent TB infection is probable and requires chemoprophylaxis in the case of remote or recent exposure to a patient with lung TB, a positive tuberculin or interferon-gamma release assay result or residual lung scars in a chest x-ray exam. PCP prevention is suggested when the patient reaches a daily dose of prednisone of 30 mg but might be needed at lower doses in case of other concomitant immunosuppressive drugs or when lymphopenia arises shortly after prednisone initiation.