Novel screening tools for latent tuberculosis: time to leave an old friend?
OBJECTIVE
Therapeutic inhibition of tumour necrosis factor-alpha strongly increases the risk of reactivation in latent tuberculosis infection. Recent blood tests based on antigen-specific T cell response and measuring production of interferon-gamma, so called interferon-gamma release assays (IGRAs), are promising novel tools to identify infected patients. The performance of diagnostic testing for latent tuberculosis infection in patients with rheumatic diseases will be discussed.


RESULTS
In patients with rheumatoid arthritis, IGRAs are more sensitive and more specific than traditional tuberculin skin testing. They are unaffected by Bacillus-Calmette-Guérin vaccination and most nontuberculous mycobacteria. Most comparative studies show a better performance of the IGRAs than tuberculin skin testing in terms of a higher specificity. The rate of indeterminate results may be affected by glucocorticoids and the underlying disease but appears independent of disease-modifying antirheumatic drugs. Despite using identical Mycobacterium tuberculosis antigens, the two commercially available tests show differences in clinical performance.


CONCLUSIONS
The current information about the performance of the tuberculin skin testing and the IGRAs in the detection of latent tuberculosis infection in patients with rheumatic diseases strongly suggest a clinically relevant advantage of the IGRAs. Their use will help to reduce overuse and underuse of preventive treatment in tumour necrosis factor inhibition.
Department of Rheumatology and Clinical Immunology/Allergology, University Hospital, University of Bern CH-3010, Switzerland. Peter.Villiger@Insel.ch
Peter M
PM
Villiger
Jean-Pierre
JP
Zellweger
Burkhard
B
Möller
D000942:Antigens, Bacterial; D018501:Antirheumatic Agents / Q000009:adverse effects; D006801:Humans; D007159:Immunologic Tests / Q000379:methods*; D007371:Interferon-gamma / Q000096:biosynthesis; D009169:Mycobacterium tuberculosis / Q000276:immunology; D012216:Rheumatic Diseases / Q000150:complications / Q000276:immunology / Q000628:therapy; D012307:Risk Factors; D013601:T-Lymphocytes / Q000276:immunology; D014374:Tuberculin Test; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000209:etiology / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors
D000942:Antigens, Bacterial; D018501:Antirheumatic Agents; D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma