AB0872 Quantiferon tb gold test in diagnosis of latent tuberculosis infection among a moroccan population with spondyloarthritis
Authors: J. Eddarami, L. Ichchou
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Patients treated with anti-tumour necrosis factor-alpha (anti-TNF-α) are at increased risk for latent tuberculosis reactivation. However, the best method for latent tuberculosis infection (LTBI) detection before initiation of anti-TNF therapy remains to be determined. <h3>Objectives</h3> The aim of this study is to investigate the role of QuantiFERON-TB Gold test as one of the interferon-gamma release assays (IGRAs) in detecting LTBI before initiation of biotherapy in a population of Moroccan patients suffering from spondyloarthritis (SpA). <h3>Methods</h3> We have conducted a cross-sectional study over two months in our department of rheumatology. All SpA patients fulfilled <sup>ASAS 2009</sup> criteria. Tuberculin skin test (TST), Quantiferon-TB Gold in Tube (QFT-GIT) assay and chest radiographs were performed before starting anti-TNF-alpha. Computed tomography was performed in patients with abnormal chest radiographs. <h3>Results</h3> We included ninety tow patients with SpA. Among them, 35 (38%) received anti-TNF-α therapy. A history of tuberculosis disease was noted in 6 patients (6.6%) (3 Pulmonary TB and 3 extrapulmonary TB). Two patients (2.2%) had contagious tuberculosis. The positive QFT-GIT rate was 15.2% (14/35). The TST was negative in 16.3% of cases (15/35). The results of QFT-GIT and TST performed in the same patients were discordant in 5 cases (5.4%). Sputum smears were negative. Chest CT performed in 29 patients had shown bronchiectasis in 3 cases (3.7%), interstitial syndrome in 2 cases (2.5%) and was normal in 24 cases (29.6%). The chemoprophylaxis was prescribed in 14 persons with a positive QFT-GIT. It was based on Isoniazid (INH) alone in 12 cases (13%), a triple therapy (RHZ) in one case (1.1%) and a quadritherapy (RHZE) in another case with active tuberculosis. The duration of chemoprophylaxis varied between 6 and 9 months in the case of monotherapy, 2 months in the case of triple therapy because of biologic hepatotoxicity and 6 months in the case of quadritherapy because of active TB occurring during anti-TNF alpha therapy. The delay in initiating biotherapy varied between 1 and 6 months. At the time of blood sampling for QFT-GIT, patients were receiving: steroids in one case (1.1%), Methotrexate (MTX) and steroids in 3 cases (3.3%), Sulfasalazine (SZP) in 3 cases (3.3%), MTX in 4 cases (4.3%) and MTX and SZP in 2 cases (2.2%). <h3>Conclusions</h3> QTB-G may be a more sensitive screening tool for LTBI <i>before initiating anti-TNF therapy</i> in immunocompromised patients, especially in a TB endemic country. <h3>References</h3> [1] Ramos S, et al. Tuberculosis screening in patients receiving biological therapy. Acta Reumatol Port2015;40:234–40. [2] Kim HC, et al. Diagnosis of latent tuberculosis infection before initiation of anti-tumor necrosis factor therapy using both tuberculin skin test and quantiFERON-TB Gold in Tube assay. Scand J Infect Dis2014;46:763–9. [3] Saidenberg-kermanac'h N, et al. Screening for latent tuberculosis in anti-TNF- candidate Patients in a high tuberculosis incidence setting. Int J Tuberc Lung Dis2012;16:1307–14. [4] Redelman-Sidi G, et al. IFN- γ Release assays in the diagnosis of latent tuberculosis infection among immunocompromised adults. AJRCCM2013;188:422–31. <h3>Disclosure of Interest</h3> None declared