[Observational study of QuantiFERON® management for ocular tuberculosis diagnosis: Analysis of 244 consecutive tests]

Introduction: Ocular tuberculosis (TB) diagnosisremains difficult and quantiferon (QFT) contribution needs still yet to be specified, despite its generalization in France. The purpose of this observational study is to assess in which ocular inflammation (OI) presentation QFT is prescribed and to evaluate the added value of new QuantiFERON®-TB Gold Plus (QFT-Plus) test for diagnosis ocular TB diagnosis.

Patients and methods: Monocentric, observational study, carried out in an ophthalmology department over a period of 5 months. Inclusion criteria were defined as an existence of an OI for which a QFT-Plus test was part of the etiological investigations. Of the 316 consecutive files, 72 were excluded (indeterminate test, prescription before anti-TNFα or immunosuppressant initiation, missing data, wrong indication) and 244 were selected and divided into two groups: group one (anterior uveitis/episcleritis, n=129) and group two (intermediate/posterior uveitis/optic neuritis/ocular myositis, n=115). All positive QFT patients underwent an etiological investigation including thoracic imaging.

Results: Forty-five patients, aged 52±12 years, had positive QFT (18.5%), including 18 patients for group 1 and 27 for group 2. Living in TB-endemic area, TB exposure and chest imaging abnormalities were identified in 70%, 27% and 22% of cases, respectively. OI was chronic in 36% of cases (group one, 4/18; group two, 12/27). None of the 18 patients, in group 1, received anti-tuberculosis treatment (ATT) or experienced a relapse during one-year follow-up. Four QFT+ patients, from group 2 (15%) had another associated disease explaining their uveitis. Among the 23 other patients without identified etiology, 13 had at least one relevant ophthalmological signs predictive of TB uveitis (posterior synechiae, retinal vasculitis and/or choroidal granuloma) (59%). Eleven patients received a 6-month ATT trial. Radiological abnormalities and granulomas at angiography were significantly more frequent among treated patients (p=0.03 and 0.001, respectively). A full OI recovery was observed for 8 patients (73%), considered ex-post as ocular TB. Nine patients in group 2 received rifampicin/isoniazid dual therapy for 3 months, but no conclusion could be drawn as to the benefit of such prescription on OI. QFT rate comparison, according to CD4 stimulation by ESAT-6/CFP-10 peptides or by CD4/CD8 co-stimulation, was comparable and found only 4 cases of discrepancy (1.6%). None of these 4 cases had ocular TB diagnosis.

Conclusion: Positive QFT frequency among patients consulting for posterior OI remains high. In this study, radiological abnormalities and granulomas at angiography seemed to be more closely related to clinician decision for starting ATT trial in QFT+ patients, which was effective in 73% of cases. QFT-Plus does not seem more relevant than QFT-TB in exploring an OI. Prospective studies are necessary to codify QFT management in the etiological assessment of OI and clearly define ATT trial indications as well as their modalities.