Usefulness of QuantiFERON®-TB Gold test in psoriatic patients under treatment with tumour necrosis factor blockers

Serial QuantiFERON-TB Gold testing in patients with psoriasis treated with ustekinumab

BACKGROUND

There is increasing concern about the risk of latent tuberculosis infection (LTBI) reactivation during the use of biologics for psoriasis. Although ustekinumab had been documented with low risk of tuberculosis, the long-term follow-up of LTBI as determined by QuantiFERON-TB Gold (QFT-G) testing in patients treated with ustekinumab is limited.

OBJECTIVES

This study aims to use serial QFT-G testing as a screening method for detecting LTBI in patients with psoriasis from an intermediate tuberculosis burden country.

METHODS

This retrospective review investigated 134 psoriatic patients in whom ustekinumab was prescribed for at least one year between 2010 and 2016 in National Taiwan University Hospital. All patients underwent annular QFT-G testing during ustekinumab therapy.

RESULTS

Among the 134 enrolled patients, baseline LTBI rate was 13.4% (18/134). Indeterminate QFT-G result was noted in 5.2% (7/134) of patients and 71.4% (5/7) of them turn to be QFT-G negative during the next testing. 81.3% (109/134) of patients had a negative QFT-G at baseline and the seroconversion rate was 7.3% (8/109) in the serial QFT-G. All the patients in the conversion group were referred to a pulmonologist for evaluation and 81.5% (22/27) of them underwent chemoprophylactic therapy while on ustekinumab. No active TB infection was noted during further follow-up with or without chemoprophylaxis.

CONCLUSIONS

This study revealed that psoriatic patients receiving long-term ustekinumab therapy had a low QFT-G conversion rate (7.3%). The clinical significance of QFT-G conversion remains controversial and needs larger scale trials to investigate.

Management of long-term therapy with biological drugs in psoriatic patients with latent tuberculosis infection in real life setting

Psoriatic patients with latent tuberculosis infection (LTBI) need a prophylaxis before starting a treatment with biological drugs. The aim of this study is to investigate the safety and efficacy of prophylaxis of LTBI in psoriatic patients receiving long-term biological drugs. The study included 56 patients (42 male and 14 female) affected by moderate-to-severe psoriasis (mean PASI: 12.8 ± 6.9 SD) treated with anti-TNF-α and/or anti IL 12, 23 and/or anti-CD11 drugs with a diagnosis of LTBI. LTBI diagnosis was based on tuberculin skin test and/or QuantiFERON TB Gold test positivity and chest X-ray suggestive, without clinical, or microbiological evidence of active disease. All patients received prophylactic therapy for 9 months with isoniazid (INH) 300 mg/day, starting 3 weeks before the beginning of biological treatment. Fifty-four patients completed prophylaxis with INH without any adverse events or intolerance; they continue the biological treatment without appearance of active tuberculosis. One patient developed tuberculosis pleurisy in course of treatment with etanercept. The infection has been treated and after a stable remission, treatment was restarted without tuberculosis reactivation. In this retrospective analysis, the prophylaxis of LTBI whit INH was effective and safe in longer follow-up period.

Detecting latent tuberculosis in compromised patients

PURPOSE OF REVIEW

The detection of latent tuberculosis infection (LTBI) in different categories of compromised patients is reviewed with focus on the role of strategies incorporating immunodiagnostic tests and analysis of epidemiological and clinical risk factors.

RECENT FINDINGS

The development of active tuberculosis (TB) is increased in compromised patients and is closely related to determinants for disease reactivation or newly acquired TB infection. A targeted detection of LTBI in these high-risk groups should be performed especially if preventive treatment is planned. The performance of immunodiagnostic tests is highly variable among different groups of immunocompromised individuals. Findings of cross-sectional studies indicate a better diagnostic accuracy of interferon-γ release assays over the tuberculin skin test. The critical issue is that in low-incidence countries, the positive and negative predictive values of any of immunodiagnostic tests were very poor. A targeted testing process involving analysis of TB risk factors increases the predictive positive values of immunodiagnostic tests and may improve LTBI detection.

SUMMARY

The LTBI detection in immunocompromised patients is a challenge. The development of new immunological biomarkers and integrated clinical and epidemiological strategies are needed to identify LTBI in compromised individuals and to plan preventive chemotherapies in those at risk of developing active TB.

Estimation of the prevalence of latent tuberculosis infection in patients with moderate to severe plaque psoriasis in Spain: The Latent study

BACKGROUND AND OBJECTIVE

Anti-tumor necrosis factor therapy for moderate to severe psoriasis can increase the risk of active tuberculosis in patients who have latent tuberculosis infection (LTBI). The main objective of this study was to estimate the prevalence of LTBI in patients with moderate to severe plaque psoriasis being treated in dermatology clinics in Spain.

MATERIAL AND METHOD

Non-interventional, cross-sectional, national epidemiological study conducted in Spain in 2011-2012. Patients with moderate to severe plaque psoriasis were included if they had undergone at least one tuberculin skin test (TST) and/or been evaluated with an interferon-γ release assay (IGRA) based on enzyme-linked immunosorbent assay (QuantiFERON(®) TB Gold In-Tube) in the 2 years preceding the study.

RESULTS

Data for 440 patients were valid for analysis. In total, 97.7% of the patients had undergone a TST, with a positive result in 23%. Of the 238 patients in whom the initial result was negative, 5% converted to positive on re-testing for a booster effect. IGRA results were available for 16.8%, 20.5% of them positive. Two of the patients with positive IGRA results had a negative TST. The prevalence of LTBI in the whole sample was 26.6%. The degree of concordance between the TST and the IGRA was moderate (κ=0.516; P<.001).

CONCLUSIONS

The prevalence of LTBI in this study was similar to previous estimates for Spain.