Tuberculin Skin Test and Quantiferon in BCG Vaccinated, Immunosuppressed Patients with Moderate-to-Severe Inflammatory Bowel Disease

• Published in: Journal of gastrointestinal and liver diseases : JGLD Vol. 24; no. 4; pp. 467 - 472
• Main Authors: Kurti, Zsuzsanna, Lovasz, Barbara Dorottya, Gecse, Krisztina Barbara, Balint, Anita, Farkas, Klaudia, Morocza-Szabo, Agnes, Gyurcsanyi, Andras, Kristof, Katalin, Vegh, Zsuzsanna, Gonczi, Lorant, Kiss, Lajos Sandor, Golovics, Petra Anna, Lakatos, Laszlo, Molnar, Tamas, Lakatos, Peter Laszlo
• Format: Journal Article
• Language: English
• Published: Romania 01-12-2015
• Subjects: Adolescent; Adult; Area Under Curve; BCG Vaccine - immunology; Biological Products - adverse effects; Chi-Square Distribution; Colitis, Ulcerative - diagnosis; Colitis, Ulcerative - drug therapy; Colitis, Ulcerative - immunology; Crohn Disease - diagnosis; Crohn Disease - drug therapy; Crohn Disease - immunology; Female; Host-Pathogen Interactions; Humans; Hungary; Immunocompromised Host; Immunosuppressive Agents - adverse effects; Interferon-gamma Release Tests; Latent Tuberculosis - diagnosis; Latent Tuberculosis - immunology; Latent Tuberculosis - microbiology; Logistic Models; Male; Multivariate Analysis; Mycobacterium tuberculosis - immunology; Odds Ratio; Opportunistic Infections - diagnosis; Opportunistic Infections - immunology; Opportunistic Infections - microbiology; Predictive Value of Tests; Prospective Studies; Reproducibility of Results; Risk Factors; ROC Curve; Severity of Illness Index; Smoking - adverse effects; Tuberculin Test; Young Adult
• ISSN: 1841-8724; 1842-1121
• DOI: 10.15403/jgld.2014.1121.244.bcg

There are few data available on the effect of immunomodulator/biological therapy on the accuracy of the tuberculin skin test (TST) and interferon-gamma release assay (IGRA) in BCG-vaccinated immunosuppressed patients with inflammatory bowel disease (IBD). Our aim was to define the accuracy, predictors and agreement of TST and IGRA in a BCG-vaccinated immunosuppressed referral IBD cohort.
166 consecutive moderate-to-severe IBD patients (122 Crohn's disease, CD and 44 ulcerative colitis, UC) were enrolled in a prospective study from three centers. Patients were treated with immunosuppressives and/or biologicals. IGRA and TST were performed on the same day. Both in- and outpatient records were collected and comprehensively reviewed.
TST positivity rate was 23.5%, 21.1%,14.5% and 13.9% when cut-off values of 5, 10, 15 and 20mm were used. IGRA positivity rate was 8.4% with indeterminate result in 0.6%. Chest X-ray was suggestive of latent tuberculosis in 2 patients. Correlation between TST and IGRA was moderate (kappa: 0.39-0.41, p<0.001). In addition, a cut-off of 14 and 17mm for TST was defined to identify IGRA positivity in a ROC analysis (AUC: 0.76, p=0.03). TST and/or IGRA positivity was not influenced by medical therapy or disease phenotype. Importantly, smoking was identified as a risk factor for TST but not IGRA positivity (OR: 2.70-5.02, p<0.01, for TSTcut-offs=5-20mm).
TST and IGRA tests are partly complimentary methods, and additional testing by TST (with a cut-off of >15mm) should be considered to identify patients at risk for latent TB. Accuracy is satisfactory in BCG-vaccinated, immunosuppressed IBD patients. Smoking is a risk factor for TST positivity.