Comparison of in vitro-specific blood tests with tuberculin skin test for diagnosis of latent tuberculosis before anti-TNF therapy

• Published in: Annals of the rheumatic diseases Vol. 66; no. 12; pp. 1610 - 1615
• Main Authors: Sellam, Jérémie, Hamdi, Haifa, Roy, Carine, Baron, Gabriel, Lemann, Marc, Puéchal, Xavier, Breban, Maxime, Berenbaum, Francis, Humbert, Marc, Weldingh, Karin, Salmon, Dominique, Ravaud, Philippe, Emilie, Dominique, Mariette, Xavier
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd and European League Against Rheumatism 01.12.2007; BMJ; BMJ Publishing Group LTD; BMJ Group
• Subjects: Adolescent; Adult; Aged; Aged, 80 and over; Antibiotics; Antigens, Bacterial - metabolism; Antitubercular Agents - therapeutic use; Bacterial diseases; Bacterial Proteins - metabolism; BCG Vaccine - administration & dosage; Biological and medical sciences; Cells, Cultured; Chi-Square Distribution; Crohn Disease - drug therapy; Crohn Disease - microbiology; Crohns disease; Extended Report; Human bacterial diseases; Humans; Immunologic Tests; Immunosuppressive Agents - therapeutic use; Infections; Infectious diseases; Interferon-gamma - metabolism; Leukocytes, Mononuclear - metabolism; Medical sciences; Middle Aged; Mycobacterium; Mycobacterium tuberculosis; Patient Selection; Patients; Population; Recombinant Proteins - metabolism; Rheumatic Diseases - drug therapy; Rheumatic Diseases - microbiology; ROC Curve; Sensitivity and Specificity; Skin; Studies; Substance abuse treatment; Thymidine - metabolism; Tuberculin Test; Tuberculosis; Tuberculosis - complications; Tuberculosis - diagnosis; Tuberculosis - drug therapy; Tuberculosis and atypical mycobacterial infections; Tumor Necrosis Factor-alpha - antagonists & inhibitors; France; Human; Radiodiagnosis; Latent tuberculosis; Exploration; Thymidine; In vitro; Blood; Inflammatory disease; Radiography; Sensitivity; Specificity; Treatment; Tumor necrosis factor; Diagnosis; Comparative study; Gamma interferon; Skin test
• ISSN: 0003-4967; 1468-2060
• DOI: 10.1136/ard.2007.069799

Introduction:Latent tuberculosis infection (LTBI) is detected with the tuberculin skin test (TST) before anti-TNF therapy. We aimed to investigate in vitro blood assays with TB-specific antigens (CFP-10, ESAT-6), in immune-mediated inflammatory diseases (IMID) for LTBI screening.Patients and methods:Sixty-eight IMID patients with (n = 35) or without (n = 33) LTBI according to clinico-radiographic findings or TST results (10 mm cutoff value) underwent cell proliferation assessed by thymidine incorporation and PKH-26 dilution assays, and IFNγ-release enzyme-linked immunosorbent spot (ELISPOT) assays with TB-specific antigens.Results:In vitro blood assays gave higher positive results in patients with LTBI than without (p<0.05), with some variations between tests. Among the 13 patients with LTBI diagnosed independently of TST results, 5 had a negative TST (38.5%) and only 2 a negative blood assays result (15.4%). The 5 LTBI patients with negative TST results all had positive blood assays results. Ten patients without LTBI but with intermediate TST results (6–10 mm) had no different result than patients with TST result ⩽5 mm (p>0.3) and lower results than those with LTBI (p<0.05) on CFP-10+ESAT-6 ELISPOT and CFP-10 proliferation assays.Conclusion:Anti-TB blood assays are beneficial for LTBI diagnosis in IMID. Compared with TST, they show a better sensitivity, as seen by positive results in 5 patients with certain LTBI and negative TST, and better specificity, as seen by negative results in most patients with intermediate TST as the only criteria of LTBI. In the absence of clinico-radiographic findings for LTBI, blood assays could replace TST for antibiotherapy decision before anti-TNF.