QuantiFERON TB-Gold--a new test strengthening long-suspected tuberculous involvement in serpiginous-like choroiditis.

Abstract

To obtain a diagnosis of tuberculosis in patients with a specific subset of uveitis, serpiginous-like choroiditis. This subset has been suspicious for tuberculous etiology in single case reports and old textbooks. Retrospective evaluation of a diagnostic test in a specific uveitis cohort. QuantiFERON is an approved, antigen-specific test that utilizes synthetic peptides representing Mycobacterium tuberculosis proteins. After incubation, interferon gamma secreted by T lymphocytes in response to these antigens is measured. We used the test in 21 of 26 patients identified from our database with serpiginous-like choroiditis. Rates of QuantiFERON positivity were compared to a group of healthy hospital employees (n = 208), another group of healthy hospital workers after tuberculosis contact (n = 117), and a group of randomly tested patients with other uveitis forms (n = 45). Eleven of 21 serpiginous-like choroiditis patients (52%) were tested positive. The rate of QuantiFERON positivity in the healthy control groups was 8.7% and 0.9%, and 13% in the other uveitis subsets. Four of the QuantiFERON-positive serpiginous-like choroiditis patients were treated with standard anti-tuberculostatic therapy; three finished the course and improved. Seven patients are either stable without therapy (n = 4) or on low-dose prednisone (n = 3). QuantiFERON testing revealed a high number of positive patients, which indicates a tuberculous etiology in this uveitis subset. Whether bacterial activity or secondary immunologic processes are causative remains a matter of speculation.