Metagenomic Next-Generation Sequencing for the Diagnosis of Infectious Uveitis: A Comprehensive Systematic Review

Background: Infectious uveitis is a potentially sight-threatening condition that requires timely and accurate pathogen identification to guide effective therapy. However, conventional microbiological tests (CMTs) often lack sensitivity and the inclusiveness of pathogen detection. Metagenomic next-generation sequencing (mNGS) offers an unbiased approach to detecting a broad range of pathogens. This review evaluates its diagnostic performance in detecting infectious uveitis. Methods: A systematic search across multiple databases identified studies assessing the use of mNGS for diagnosing infectious uveitis. The included studies compared mNGS to CMTs, including polymerase chain reaction (PCR), culture, serology, and the IGRA (Interferon-Gamma Release Assay). The study characteristics; the detection rates; and the sensitivity, specificity, and predictive values were extracted. The sensitivity and specificity of mNGS were calculated using CMTs as a reference. Results: Twelve studies comprising 859 patients were included. The sensitivity of mNGS compared to that of CMTs ranged from 38.4% to 100%, while specificity varied between 15.8% and 100%. The commonly detected pathogens included varicella-zoster virus, cytomegalovirus, Toxoplasma gondii, and herpes simplex virus. In some cases, mNGS outperformed PCR in viral detection, aiding diagnosis when the standard methods failed. However, contamination risks and inconsistent diagnostic thresholds were noted. Conclusions: mNGS enables the diagnosis of infectious uveitis, particularly for viral causes, but its variable performance and standardization challenges warrant further investigation.