[Tuberculosis risk among patients with systemic diseases].

The incidence of tuberculosis among patients with systemic rheumatic diseases is much higher than in the general population (the risk is multiplied by 5 to 15 in patients with systemic lupus erythematosus). Reactivation of a latent tuberculosis is frequent, as assessed by the short delay of occurrence after a systemic rheumatic disease has been diagnosed. Besides immunosuppression induced by the underlying disease, the role of glucocorticoids and of immunosuppressive therapy including biotherapies using TNF antagonists must be underlined. Tuberculosis in such patients frequently presents as extrapulmonary or disseminated disease. A screening of tuberculosis is recommended before anti-TNF therapy, and includes previous history questioning, chest X ray, tuberculin skin test with 5 international units of tuberculin. Immunological methods of tuberculosis detection are under evaluation in these patients. If a latent tuberculosis infection is diagnosed, a specific tuberculosis chemoprophylaxis, started at least 3 weeks before initiation of TNF antagonists, has allowed to reduce the occurrence of anti-TNF-associated tuberculosis in patients living in Europe and North America. The screening strategies for tuberculosis should probably be extended in all patients with systemic rheumatic diseases receiving glucocorticoids and/or immunosuppressive therapy.