Respiratory infections associated with anti-TNFα agents.

Anti-TNFα agents have proved effective in the treatment of various inflammatory, rheumatologic, dermatologic, and gastrointestinal diseases. Severe respiratory tract infections of bacterial or fungal origin have emerged as important complications in patients receiving such treatments. The risk of infection due to anti-TNFα therapy is difficult to assess in these patients who are immunocompromised because of the underlying disease itself and of previous or concomitant immunosuppressive drugs. This excessive infection risk seems real, particularly in the first six months following treatment initiation, and higher for patients receiving anti-TNFα monoclonal antibodies than for those receiving soluble TNFα receptor. The involved pathogens are pyogenic bacteria but also Mycobacterium tuberculosis, mostly by reactivation of latent tuberculosis infection, warranting a systematic preventive approach to screening and chemoprophylaxis before initiating the anti-TNFα therapy. In countries with low tuberculosis endemicity, an increased prevalence of nontuberculous mycobacterial infections has been reported. The incidence rate of legionellosis is high in this population. In case of pneumonia, empirical antibiotic therapy should cover Legionella pneumophila. Several cases of histoplasmosis have also been reported and this diagnosis should be suspected in patients who have traveled to endemic areas. Other opportunistic infections have been reported including Pneumocystis pneumonia, aspergillosis, and nocardiosis mostly in patients receiving other immunosuppressive treatments. The risk of infection should be evaluated as an individual risk depending on comorbidities and past or concomitant treatments.