Mediterr J Rheumatol 2015; 26(1): 72-73
Frequent conversion of screening tests for tuberculosis (Mantoux, IGRAs) in patients on anti-TNF treatment

Objective. Sceening test for tuberculosis (Mantoux, IGRAs) are established tests before the initiation of anti-TNF treatment. Their role in the follow up of patients remains unknown. The aim of the study was to investigate the frequency of positive screening tests for tuberculosis during treatment with anti-TNF agents in patients with negative tests

Materials and methods. We studied 70 patients (RA, n=33, spondyloartritides, n=33, other diseases, n=4) with negative screening tests before the initiation of anti-TNF treatment (Mantoux < 5mm, IGRAs: IGRAs: T.Spot®-TB and QuantiFERON®-TB Gold In Tube/QFT-GIT (-)]. One year after the initiation of anti-TNF (adalimumab n=27, etanercept n=14, infliximab n=16, golimumab n=8, certolizumab pegol n=5) all patients underwent in re-screening (Mantoux, IGRAs).

Results. In 20 patients (29%) there was a conversion of at least one test: 9 patients (13%) had positive Mantoux (≥ 5 mm), 7 (10%) positive T.Spot®-TB and 5 (7%) had positive QFT-GIT. One patient was positive for ≥1 tests, while one patient with confirmed exposure to M.Tb during treatment had positive T.Spot®-TB. In multivariable analysis, only Infliximab correlated with decreased frequency of positivity of a test (p=0.017). Active ΤΒ was not detected in any patient (40% of patients received isoniazid) during 27 ± 12 months of follow up.

Conclusion. Approximately 1/3 of patients with negative pro-treatment screeing test for TB had at least a positive ΤΒ test during treatment. These findings should be evaluated for the appropriate strategy of follow up of patients under anti-TNF treatment.