Background The advent of biological treatments has greatly improved the management of chronic inflammatory diseases (CID). However, these biologics increase the risk of infection including the possible development of tuberculosis (TB). Screening of latent tuberculosis infection (LTBI) is therefore necessary prior to their initiation, especially in Tunisia, which is considered as a high-incidence area of TB.
Objectives The aims of this study were to identify the prevalence of LTBI among patients candidate to initiate biologics, to analyze the tolerance of preventive therapy and to detect active TB or conversions of immunodiagnostic tests under biologics.
Methods A retrospective study was conducted, over a period of 14 years (2002–2016). Patients with CID, candidate to initiate biological treatment, were included. The screening of LTBI was performed according to the national Tunisian guidelines. Clinical data, screening and follow-up information on biological therapy were assessed.
Results A total of 76 patients were enrolled in the study, 32 men and 44 women with a mean age of 66 years [17–80]. Rheumatoid arthritis (RA) was the most common CID (44%). The diagnosis of LTBI was established in 16 cases (21%). Among them, 3 had a Tuberculin Skin Test (TST) more than 10mm associated with a positive Interferon Gamma Release Assay (IGRA), 11 had only a positive TST, and 2 had only a positive IGRA. One of them had a history of pulmonary TB but adequately treated. All patients with positive screening were considered for preventive treatment. Thirteen (81%) received an association of isoniazid-rifampicin for 3–6 months, and 3 (19%) received isoniazid for 6 months. Toxicity was reported in 4 cases (25%): hepatotoxicity (n=1), dermatologic toxicity (n=1), fever (n=1) and stomachache (n=1). During the follow-up period, no case of reactivation has been reported among patients with LTBI. Out of the 60 patients with negative baseline screening, only 4 have been re-screened (6%) and none had conversions in immunodiagnostic tests. However, among patients who screened negative, one case of active pulmonary TB has been reported in a woman who had an ankylosing spondylitis (AS) and who was receiving infliximab during 22 weeks. She hadn't previous TB history or new TB exposure.
Conclusions Our study showed that the Tunisian recommendations allowed detecting a LTBI in 21% of biologic therapy candidates. The initial screening and the prophylactic treatment improve the safety of these treatments. However, we noted a low rate of re-screening, as the Tunisian guidelines do not recommend annual screening. Wide studies should be designed in order to evaluate the efficacy of re-screening.
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Disclosure of Interest None declared