Screening for latent tuberculosis infection in patients with inflammatory bowel disease: Can interferon-gamma release assays replace the tuberculin skin test?

Impact of Immunosuppressive Therapy on the Performance of Latent Tuberculosis Screening Tests in Patients with Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis

Screening for latent tuberculosis infection (LTBI) is mandatory before commencing tumor necrosis factor (TNF)-α inhibitor use. However, the impact of immunosuppressive therapy (IST), including corticosteroids and immunomodulators, on the performance of LTBI screening in patients with inflammatory bowel disease (IBD) has not been fully elucidated. We searched all relevant studies published before November 2021 that examined the performance of interferon γ release assays (IGRAs) and tuberculin skin tests (TSTs) in patients with IBD who received IST, using the Medline, EMBASE, and Cochrane Library databases. We performed meta-analyses of positive or indeterminate rates of IGRA or TST according to IST and calculated the concordance rates between IGRA and TST results. A total of 20 studies with 4045 patients were included in the meta-analysis. The IGRA-positive rate was lower in patients on IST than in those not on IST (odds ratio (OR) (95% confidence interval (CI)) = 0.55 (0.39–0.78)), whereas the IGRA-indeterminate rate was higher in patients on IST than in those not on IST (OR (95% CI) = 2.91 (1.36–6.24)). The TST-positive rate did not differ between the on-IST and not-on-IST groups (OR (95% CI) = 0.87 (0.51–1.50)). The concordance rate between IGRA and TST was 83.3% (95% CI, 78.5–88.1%). The IGRA-negative/TST-positive rate tended to be higher than that the IGRA-positive/TST-negative rate (9.5% vs. 5.8%, respectively), although the difference was not statistically significant. In conclusion, IGRA results were negatively affected by IST in patients with IBD, supporting requirements that IGRA should be performed before initiating IST. The use of both an IGRA and TST in patients with IBD on IST may improve the diagnosis rate of LTBI.

Active tuberculosis in inflammatory bowel disease patients under treatment from an endemic area in Latin America

BACKGROUND

There has been an increase in cases of inflammatory bowel disease (IBD) in recent years. There is also greater access and availability of immunosuppressive and biological agents, which increase the risk of opportunistic infection despite improving the quality of life and promoting mucosal healing. Tuberculosis (TB) remains a public health problem, and it has a high incidence in several countries. Therefore, knowledge of the risk of developing TB in patients with IBD is important.

AIM

To evaluate the risk of active TB in patients with IBD under treatment from an endemic area in Latin America.

METHODS

A standard questionnaire included demographic variables, clinical aspects of IBD disease, history of active TB during treatment, active TB characteristics and evolution, initial screening and results and time from the start of anti-tumor necrosis factor alpha (TNFα) to TB development.

RESULTS

Azathioprine, anti-TNFα and the combination of these two drugs were associated with a higher risk of active TB incidence. The TNFα blockers increased the relative risk of developing active TB compared to other treatments. All four multivariable models showed that the use of TNFα blockers alone or in combination with azathioprine was an important risk factor for the incidence of active TB. After adjustment for sex, age, type of IBD and latent TB, anti-TNFα with azathioprine increased the relative risk to 17.8 times more than conventional treatment. Late TB, which was diagnosed 3 mo after the start of anti-TNFα, was the most frequent.

CONCLUSION

Treatment with anti-TNFα increased the risk of active TB in IBD patients from an endemic area in Latin America. This risk was increased when anti-TNFα was combined with azathioprine. The time from the beginning of the treatment to the active TB diagnosis suggests a new TB infection.

Recommendations of the Spanish Working Group on Crohn's Disease and Ulcerative Colitis (GETECCU) on screening and treatment of tuberculosis infection in patients with inflammatory bowel disease

There is evidence that following the recommendations on screening and treatment of tuberculosis infection does not completely prevent the onset of tuberculosis in patients with inflammatory bowel disease. This fact, and the increasing use of new biologics and immunomodulators, has led the Spanish Group Working on Crohn's Disease and Ulcerative Colitis to update their recommendations for the prevention of tuberculosis in patients with inflammatory bowel disease. Diagnostic methods for latent tuberculosis infection, different scenarios in which screening is to be performed, strategies to reduce the risk of tuberculosis once biological treatment is initiated and chemoprophylaxis guidelines for latent tuberculosis infection are reviewed, as well as the management of active tuberculosis during biological treatment. Finally, there is a summary of the current recommendations within the paper and in an algorithm.

Performance of Interferon-Gamma Release Assays for Tuberculosis Screening in Pediatric Inflammatory Bowel Disease

OBJECTIVES

The aim of the study was to analyze the diagnostic accuracy and utility of QuantiFERON-TB Gold In-Tube, an interferon-gamma release assay (IGRA), as a screening tool for latent tuberculosis infection (LTBI) in pediatric patients with inflammatory bowel disease (IBD) undergoing treatment with anti-tumor necrosis factor (anti-TNF) medications. To describe cases of tuberculosis in the pediatric IBD population, TB treatment courses, outcomes, and their effect on IBD management.

METHODS

A single-center, retrospective cohort study of pediatric IBD patients who underwent tuberculosis screening. IGRA testing from 2011 to 2017 were analyzed to determine result rates, characteristics, and outcomes.

RESULTS

One thousand seven hundred fifty-four (1,754) tests were performed on 859 patients. One thousand six hundred thirty-four (1,634) tests were negative, 9 were positive, and 111 were indeterminate. Eight of 9 positive tests resulted during repeat annual screening while receiving IBD treatment. Five patients were treated for latent tuberculosis infection (LTBI), and 4 were false-positives. IBD therapy was interrupted in 3 patients, with no negative long-term outcomes. We report 1 known false-negative, in a patient who developed disseminated TB on anti-TNF therapy. Indeterminate testing rates were higher at IBD diagnosis than during treatment (10.3% vs 5.3%, P < 0.001). Follow-up testing of indeterminate results was negative in all patients retested, with 14 patients lost to follow-up. No patient with indeterminate testing developed TB.

CONCLUSIONS

IGRAs are a useful tool to screen for LTBI, both before anti-TNF therapy and during treatment. Results should be used in concert with detailed history and examination. Positive and indeterminate results should be promptly repeated for timely TB diagnosis and to minimize interruptions in IBD therapy.