Interferon-gamma autoantibodies in patients with infectious uveitis: a pilot case-control study.

BACKGROUND: To investigate the association between infectious uveitis in immunocompetent individuals and adult-onset immunodeficiency (AOID). METHODS: A pilot prospective observational case-control study was conducted involving 28 patients with infectious uveitis unrelated to human immunodeficiency virus (non–HIV). These patients were categorized into two groups: Cytomegalovirus (CMV)–associated uveitis (n = 15) and non–CMV infectious uveitis (n = 13). Blood donors (n = 41) served as controls to establish the positivity threshold for interferon-gamma (IFN-γ) autoantibodies. Autoantibody and neutralizing autoantibody levels were measured using indirect and competitive ELISA methods, respectively. Demographic data, key clinical characteristics, disease course and laboratory investigations—including complete blood count, anti–HIV antibody test, and CD4+ T-cell count—were collected from participants. RESULTS: One patient in the CMV group tested positive for IFN-γ autoantibodies (level: 1.02), exceeding the 99th percentile positivity threshold defined by the control group. This patient, diagnosed with AOID, also had the highest neutralizing autoantibodies level (41.02%) and presented with severe CMV anterior uveitis and endotheliitis leading to bullous keratopathy and corneal decompensation. There were no differences in demographic data or basic immunologic parameters between the CMV and non-CMV groups. Likewise, no significant differences in IFN-γ autoantibody level were observed among cases and controls, with median (IQR) value of 0.15 (0.12–0.21) in CMV group; 0.14 (0.11–0.17) in non-CMV groups; and 0.14 (0.12–0.18) in control group (P > .05). CONCLUSIONS: In this pilot study, one patient with severe CMV–associated uveitis was identified as having underlying AOID. The findings are hypothesis-generating, and an association cannot be established from the current data. The pathogenesis of infectious uveitis in presumed immunocompetent individuals remains unclear and warrants further investigation. CLINICAL TRIAL NUMBER: Not applicable.