Retesting for latent tuberculosis in IBD treated with TNF-α inhibitors

The latest issue of the Alimentary Pharmacology & Therapeutics investigates retesting for latent tuberculosis in patients with IBD treated with TNF-α inhibitors.

Patients treated with TNF-α inhibitors are at high risk of reactivation of latent tuberculosis.

Prospective studies on monitoring of TB reactivation and/or infection in this risk group are lacking.
 
Dr Reinisch from Austria tested the conversion and reversion rate of screening tests for latent TB serial tuberculin skin test, and interferon-γ release assay under ongoing TNF-α inhibitors therapy.
 
The research team retested consecutive patients with IBD receiving TNF-α inhibitors therapy for a minimum of 5 months for latent tuberculosis using interferon-γ release assay and tuberculin skin test.

A detailed patient history, and concomitant therapy were recorded for each subject.
 
After a median of 35 weeks, interferon-γ release assay was retested in 184 out of 227 patients still under index TNF-α inhibitors.

14% of patients with baseline positive tuberculin skin test reverted to negative

Alimentary Pharmacology & Therapeutics

The team found that tuberculin skin test was available in 78% of subjects.

The majority of patients were TNF-α inhibitors naïve.

In a subgroup of patients who received isoniazid due to diagnosis of latent TB at baseline, 46% of patients with baseline positive interferon-γ release assay, and 14% of patients with baseline positive tuberculin skin test reverted to negative at retesting.

The team noted that in patients without diagnosis of latent tuberculosis at baseline no permanent interferon-γ release assay conversion was observed, but there were 4% with tuberculin skin test conversions from negative to positive.

The research team found no single case of TB reactivation or infection was recorded during the observation period.
 
Dr Reinisch's team concludes, "During treatment TNF-α inhibitors conversion was observed for tuberculin skin test, but not interferon-γ release assay."

"As compared with tuberculin skin test, interferon-γ release assay reverted in nearly half of isoniazid-treated patients for latent tuberculosis."

"However, the fact that patients in whom the interferon-γ release assay test result remained positive did not develop active tuberculosis during follow-up questions the utility of interferon-γ release assay as a monitoring tool during chemoprevention."