Abstract
Introduction. Screening for latent tuberculosis infection (LTBI) prior to the prescribing of anti-TNF agents and monitoring for infection during treatment are recommended. Aims. We assessed the efficacy of serial interferon-gamma release assays (IGRAs) for the diagnosis and monitoring of latent tuberculosis infection (LTBI) in patients receiving immunosuppressive agents for treatment of rheumatic diseases, in an endemic area. Methods. We conducted a prospective study on patient candidates to biologic agents. QuantiFERON-TB Gold In-Tube (QFT-GIT) was performed at baseline and after 3 and 6 months since biologic onset. A further follow-up period of 6 months was observed. Results. Among patients enrolled (n = 66, F = 57.6%), 13 (19.7%) had at least 1 risk factor for LTBI. Fifty-three were taking immunosuppressants at the time of TB testing. At baseline, 16 (24.2%) patients displayed positive, 43 (65.2%) negative, and 7 (10.6%) indeterminate QFT-GIT results.69.7% (n=46) pacients showed consistent IGRA results during follow-up, and, 19.7% (n=13) had consistently positive results. QFT-GIT conversion rate was 12.1% (8/66) and reversion rate was 4.5% (3/66). QFT-GIT results changed of 28 % at month 3 and of 21 % at month 6; the greatest change was observed in patients with indeterminate results that became negative (15 %; p < 0.02). Conclusions. The routine use of QFT-GIT at screening seems not to give any advantage in the setting of patients awaiting biologics. In addition, the feasibility of serial QFT-GIT during biologic therapy needs definition since changes in IFN-γ levels may occur without a pathologic connotation.
- © 2013 ERS
