ABSTRACT
OBJECTIVES: High accuracy diagnostic screening tests for tuberculosis (TB) are required to improve the diagnosis of both active TB and latent Mycobacterium tuberculosis (MTB) infection (LTBI). The novel IGRA LIOFeron®TB/LTBI assay was tested and its accuracy was compared to the QuantiFERON®-TB Gold Plus assay. METHODS: A total of 389 subjects were enrolled in two cohorts and classified as healthy, active TB or LTBI persons. The blood of all the patients was tested with LIOFeron®TB/LTBI assay, containing MTB alanine dehydrogenase, able to differentiate active TB from LTBI diagnosis. The results obtained with both IGRAs, performed on the same 250 samples, were finally compared. RESULTS: The two assays demonstrated an excellent concordance of their results with patients' diagnosis of MTB infection. ROC analysis for QuantiFERON®-TB Gold Plus showed sensitivity and specificity respectively of 98% and 97% in diagnosing active TB patients and 85% and 94% in diagnosing LTBI subjects. LIOFeron®TB/LTBI assay showed sensitivity and specificity respectively of 90% and 98% in diagnosing active TB patients and 94% and 97% in diagnosing LTBI subjects. CONCLUSIONS: The two IGRAs displayed the same high accuracy in diagnosing MTB infection/TB disease, and LIOFeron®TB/LTBI assay demonstrated higher sensitivity than QuantiFERON®-TB Gold Plus test in LTBI detection.
Subject(s)
Diagnostic Tests, Routine/methods , Latent Tuberculosis/diagnosis , Adult , Aged , Cohort Studies , Female , Humans , Latent Tuberculosis/immunology , Latent Tuberculosis/microbiology , Male , Middle Aged , Mycobacterium tuberculosis/genetics , Mycobacterium tuberculosis/isolation & purification , Mycobacterium tuberculosis/physiology , ROC Curve , Sensitivity and Specificity , T-Lymphocytes/immunologyABSTRACT
Nontuberculous mycobacteria are the most frequent cause of chronic cervical lymphadenitis in childhood. The aim of the study was to evaluate the performance of IL-2, IL-17, and INF-γ in-house enzyme-linked immunospot assays using a Mycobacterium avium lysate, in order to identify a noninvasive diagnostic method of nontuberculous mycobacteria infection. Children with subacute and chronic lymphadenopathies or with a previous diagnosis of nontuberculous mycobacteria lymphadenitis were prospectively enrolled in the study. Sixty children with lymphadenitis were included in our study: 16 with confirmed infection (group 1), 30 probable infected (group 2) and 14 uninfected (group 3). Significantly higher median cytokine values were found in group 1 vs group 2, in group 1 vs group 3, and in group 2 vs group 3 considering IL-2-based enzyme-linked immunospot assay (p = 0.015, p < 0.001, p = 0.004, respectively). INF-γ-based enzyme-linked immunospot assay results were significantly higher in group 2 vs group 3 (p = 0.010). Differences between infected and uninfected children were not significant considering IL-17 assays (p = 0.431). Mycobacterium avium lysate IL-2 and INF-γ-based enzyme-linked immunospot assays seem to be promising noninvasive diagnostic techniques for discriminating children with nontuberculous mycobacteria lymphadenitis and noninfected subjects.
