The value of an immune response to Mycobacterium tuberculosis in patients with chronic posterior uveitides revisited: utility of the new IGRAs

Abstract

To explore the utility of a specific immune response to Mycobacterium tuberculosis in a population of immunosuppressed idiopathic chronic posterior uveitis patients, by means of a tuberculosis-specific interferon-gamma release assay. Prospective, interventional case series. A total of 31 referred patients with severe idiopathic chronic uveitis or panuveitis and 52 controls were screened for a specific immune response to tuberculosis. After ruling-out specific uveitis entities, presumed tuberculosis-related uveitis was initially considered when ophthalmologic findings were consistent with tubercular uveitis, and a specific immune response to M. tuberculosis confirmed by QuantiFERON, despite inability to detect M. tuberculosis. Clinical responses to antitubercular treatment were recorded. The prevalence of an immune response to M. tuberculosis was 15.38% in controls and 32.25% in uveitis patients (OR=2.619, P=0.07). Two patients were QuantiFERON indeterminate (6.4%). After excluding seven specific uveitis entities (OR=3.66, P=0.03), eight QuantiFERON-positive and one QuanTIFERON-negative uveitis patients were initially treated for presumed tuberculosis-related uveitis. All but one had no evidence of active systemic involvement. None had been previously diagnosed with tuberculosis, but unsuccessfully treated with immunosuppressors. After a 9-month tuberculostatic treatment, seven QuantiFERON -positive and one QuantiFERON-negative patients exhibited decreased intraocular inflammation, visual acuity improvement, and no relapses. Estimated QuantiFERON sensitivity and specificity were 82 and 100%, respectively, with a PPV=100% and an NPV=86%. QuantiFERON was useful for antituberculous treatment decision-making in chronic posterior uveitis immunosuppressed patients from areas with an intermediate-high prevalence of tuberculosis.