AB0570 Different cut off of tuberculin skin test in latent tuberculosis screening in systemic lupus erythematosus, rheumatoid arthritis and ankylosing spondylitis with an intermediate tuberculosis burden population
Authors: Y.-J. Jan Wu, Y.-C. Liu, S.-C. Chen
Journal: Annals of the Rheumatic Diseases (2013)

<h3>Background</h3> Screeing latent TB before biologic or immunosuppression thearpy is important in high incidence of tuberculosis population. <h3>Objectives</h3> Objective:To investigate the roles of tuberculin skin test and interferon-gamma stimulation test in the diagnosis of latent tuberculosis infection in patients with systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and ankyolosing spondylitis (AS). <h3>Methods</h3> Methods: The study enrolled 329 consecutive patients, 62 with SLE, 179 with RA, and 88 patients with seronegative spondyloarthropathy (SSA; 82 with AS and 6 with undifferentiated spondyloarthropathy). Tuberculin skin test (TST) was performed by Tuberculin PPD RT23 SSI 2 TU/0.1ml. Interferon-γ assay was performed by QuantiFERON-TB Gold (QFT). Receiver operating characteristic (ROC) curve analysis was used to determine the optimal cut-off point for latent TB on the PPD test. <h3>Results</h3> Results: A positive QFT-G result was observed in 17.9% RA, 15.9% SSA, and 11.3% patients with SLE. There was no statistically significant association between QFT-G result and sex, disease duration, prednisone use, or use of disease-modifying antirheumatic drugs. Men had a multivariate-adjusted OR of 2.53 (95% CI, 1.3-4.92) for a positive PPD result (if defined as an induration ≥10 mm). In RA patients, QFT was found best differentiated with PPD≧ 10.5 mm. Among RA patients, the optimal PPD cut-offs for women, men, prednisone users, and prednisone nonusers were ≥10.5 mm, ≥10 mm, ≥10.5 mm, and ≥10.5 mm, respectively. SSA patients were best differentiated with a PPD induration ≥16.5 mm; however, the optimal cut-off for SLE patients was a PPD induration ≥9 mm. <h3>Conclusions</h3> Conclusions: TST in LTB screening remains useful due to its low cost. In patients who will receive biologic therapy an induration of PPD 5mm as positive cute-off for TST needs to be reconsidered. For RA patients PPD≥10 mm, SSA patients ≥16.5 mm in our BCG vaccinated and intermediate tuberculosis burden population maybe appropriate. For those who had anergic TST result should have IGRA test performed, this would cut down on cost and avoidance of unnecessary prophylaxis of latent TB therapy. <h3>References</h3> Carmona L, Gómez-Reino JJ, Rodríguez-Valverde V, Montero D, Pascual-Gómez E, Mola EM, et al. Effectiveness of recommendations to prevent reactivation of latent tuberculosis infection in patients treated with tumor necrosis factor antagonists. <i>Arthritis &amp; Rheumatism</i> 2005;52(6):1766-72. Chen DY SG, Hsieh TY, Hsieh CW, Lan JL. Effectiveness of the Combination of a Whole-Blood Interferon-Gamma Assay and the Tuberculin SkinTest in Detecting Latent Tuberculosis Infection in Rheumatoid Arthritis Patients Receiving Adalimumab Therapy. <i>Arthritis &amp; Rheumatism (Arthritis Care &amp; Research)</i> 2008;59:800–06. Ho H-H, Lin M-C, Yu K-H, Wang C-M, Wu Y-JJ, Chen J-Y. Pulmonary tuberculosis and disease-related pulmonary apical fibrosis in ankylosing spondylitis. <i>Journal of Rheumatology</i> 2009;36(2):355-60. Targeted tuberculin testing and treatment of latent tuberculosis infection. <i>Am J respire Crit Care Med</i> 2000;161:S221-47. <h3>Disclosure of Interest</h3> None Declared