QuantiFERON-TB Gold Plus for screening and monitoring latent tuberculosis infection in spondyloarthritis patients.

Introduction: The optimal frequency of rescreening for latent tuberculosis infection (LTBI) in patients with inflammatory arthritis on biologic/targeted-synthetic disease modifying anti-rheumatic drugs (b/ts-DMARDs) is uncertain. We aimed to evaluate the impact of LTBI re-screening using the QuantiFERON-TB Gold Plus (QFT-Plus; QIAGEN, Germantown, USA) test method and to assess the frequency of re-screening in real-life spondyloarthritis (SpA) patients on b/ts-DMARDs.

Methodology: This study focused on patients with SpA who were scheduled for b/ts-DMARDs therapy and underwent QFT-Plus testing to screen for LTBI. The study analyzed whether QFT-Plus test negative patients underwent sequential QFT-Plus tests during follow-up and the timing of these tests. Cases of tuberculosis (TB) reactivation were documented, and the clinical status of affected patients were recorded.

Results: Of the 801 patients included in the study, the QFT-Plus tests were negative in 701 (87.5%), positive in 89 (11.1%), and indeterminate in 11 (1.3%) patients. The median follow-up of patients with initial QFT-Plus test negative was 33.6 months (min-max: 3-76.3). Follow-up tests were carried out on only 59 (8.4%) of these 701 patients. Of the rescreened 59 patients, 56 had negative results, 3 had positive results. TB was developed in only 2 (0.25%) of the 801 patients during follow-up.

Conclusions: Assessment of LTBI in patients with SpA using interferon-gamma release assays (IGRAs) test is rational. Performance of annual testing of IGRAs in patients who were QFT negative was low in our SpA cohort. National and international guidelines may need to be updated to reflect real-world data and clinical practice.