Comparıson of tuberculın skın test, quantıferon-TB gold test and T-SPOT.TB test ın patıents wıth rheumatıc dıseases planned to receıve tnf blockıng agents for the ıdentıfıcatıon of latent tuberculosis ınfectıon

Objective: We aimed to compare Tuberculin Skin Test (TST) and QUANTIFERON-TB GOLD test and T-SPOT.TB test as new diagnostic tools that can be used in patients with rheumatic diseases planned to receive tumor necrosis factor (TNF) blocking agents for the identification of latent tuberculosis infection in this study. Materials and Method: In this study, 49 patients (20 male, 29 female) who applied to Adnan Menderes University, Faculty of Medicine, Department of Internal Medicine, Immunology and had rheumatic diseases and planned to receive TNF blocking agents were analyzed. Age, sex, comorbidities, medications, number of BCG scar and TST, QuantiFERON-TB Gold and T-SPOT.TB test results were determined in the evaluated patients. The datas obtained from this study were evaluated with using SPSS 17.0 (Statistical Package for the Social Science, version 17.0) program. Results: 27 patients had rheumatoid arthritis (RA), 22 patients had ankylosing spondylitis (AS) in the patients who had rheumatic diseases and planned to receive TNF blocking agents and the average age was 47.87 ? 11.16 (23-71 years). In one patient (2%) had no BCG scar, the remaining 48 patients (98%) had BCG vaccination and the mean steroid dose was 6.79 mg prednisolone. The prevalence of latent tuberculosis infection for TST was 61.2%, for QuantiFERON-TB Gold test was 14.3% and for T-SPOT.TB test was 32.7%. There was no statistically significant difference between the results of number of BCG scar and TST (p=0.176), Quantiferon TB-Gold test (p = 0778) and T-SPOT.TB test (p = 0.612). Considering all patients, Quantiferon TB-Gold test specificity was 88.2%, sensitivity was 17.2% and the T-SPOT.TB test sensitivity was 32.1%, specificity was 56.3%. Evaluation of sub-group of the study was as follows; Evaluation of sub-group of the study is as follows; QuantiFERON-TB Gold test sensitivity was 15.4%, specificity was 83.3% and the T-SPOT.TB test sensitivity was 57.1%, specificity was 60% according to TDT in patients with RA. Evaluated in patients with a diagnosis of AS, Quantiferon TB-Gold test the sensitivity was 18.8%, specificity was 100% and sensitivity of T-SPOT.TB test was 7.1%, specificity was 50%. There was low agreement between TDT and Quantiferon TB-Gold (?=0.043) and the T-SPOT.TB test (?=0.1). There was no statistically significant relationship between steroid therapy and negative test results (p>0.05). Conclusion: Interferon-?-based tests carrying no common antigens with BCG was previously not affected by vaccination. Tests can be used in patients with rheumatic diseases planned to receive TNF blocking agents for the identification of latent tuberculosis infection depending on the sensitivity and specificity. However, more studies are needed to determine the actual sensitivity and specificity. Keywords: Inflammatory rheumatic diseases, TNF blocking agent, TST, Quantiferon TBGold test, T-SPOT.TB test, latent tuberculosis infection