Role of Interferon-Gamma Release Assay for the Diagnosis and Clinical Follow up in Ocular Tuberculosis

Abstract

Purpose: To assess the performance of interferon-gamma release assay (IGRA) associated with tuberculosis skin test (TST) for ocular tuberculosis (OTB) diagnosis and therapeutic decision making.

Method: One hundred and ninety-one patients with ocular inflammation were prospectively followed-up. Patients with clinical signs highly suspected of OTB, TST≥10 mm, and/or IGRA≥0.35 IU/mL received antitubercular therapy (ATT). Sensitivity (Se), specificity (Sp), and area under the curve (AUC) were assessed.

Results: Seventy-two (37.7%) patients received ATT for presumed OTB. Combining TST and IGRA had Se=89.6%, Sp=99.2%, and AUC (0.98) significantly higher compared to TST (0.85, Z=6.3, p<.001) or IGRA (0.95, Z=2.5, p=.01). Prior history of corticosteroids or immunosuppressant with concomitantly oral prednisone and baseline IGRA> 2.0 IU/mL was associated significantly with more recurrences in ATT patients (p=.01) .

Conclusion: Considering TST and IGRA together was more effective in assessing OTB diagnosis. The real value of the IGRA test to predict recurrences needs further studies.

Keywords: Ocular tuberculosis; antitubercular treatment; diagnosis; interferon gamma release assay; tuberculosis skin test.