QuantiFERON TB-gold conversion rate among psoriasis patients under biologics: a 9-year retrospective study

Tuberculosis (TB) screening is mandatory for psoriasis biologic treatment. However, evidences regarding TB screening results during biologic treatment are conflicting.

The aim of this study is to evaluate the rate of QuantiFERON TB Gold test (QFT) conversion in psoriasis patients during biologics over time.

A 9-year single center retrospective study was performed in order to evaluate the rate of QFT conversion in patients affected by moderate-to-severe plaque psoriasis under available biological therapies (anti-TNF-α, IL-12/23, IL-17). For each patient, demographic data, age, gender, comorbidities, previous psoriasis therapy, as well as ongoing treatment type were registered. Five-hundred twenty-six patients (61.2% male, with a mean age of 52.6 ± 13.9 years) treated with biologics were enrolled.

QFT conversion occurred in 6.5% of patients over a mean treatment duration of 3.2 years. On average, QFT conversion occurred after 34.05 months of treatment. Anti-TNF-α drugs, and among them, adalimumab above all (35.5% of all cases), were the most commonly involved treatment during QFT conversion, followed by anti-IL-12/23 (17.6%) and anti-IL-17 (14.7%). However, differences among biologics class or single biologics (adalimumab, etanercept, infliximab, golimumab, certolizumab, ustekinumab, ixekizumab, secukinumab) did not approach statistical significance.

Annual TB screening is important in psoriasis patients under biologic treatment in order to avoid possible latent TB infection reactivation. Indeed, our data showed that even in a low TB prevalence country like Italy, QFT may convert over time in psoriasis patients under biologics in 6.5% of the cases.