Idiopathic uveitis is the most commonly seen subtype of uveitis in tertiary care centers, but experts note that the term idiopathic—denoting a disease of unknown cause or one that arises spontaneously—“fails to convey prognostic or therapeutic implications to providers or patients.” To shed light on this particular uveitis subtype and its terminology, researchers turned to gene expression technology to study possible further subtypes of idiopathic uveitis.

After analyzing gene expression from cells in peripheral blood, the researchers realized  that subtypes of uveitis associated with systemic disease display distinctive patterns of gene expression. In this study, the researchers discovered that these gene expressions patterns can help to classify some types of idiopathic uveitis.

The case control study involved gene profiling for patients with  idiopathic uveitis (n=38) or uveitis associated with one of four systemic diseases, including axial spondyloarthritis (n=17), sarcoidosis (n=13), inflammatory bowel disease (n=12), tubule-interstitial nephritis (n=10). The study also included a control group of 18 healthy individuals.

The researchers extracted the 20 most distinctive genes for each diagnosis and compared them with the control group. Of the 80 genes extracted, 75 were unique. The researchers then used a classification algorithm to see whether the genes from patients with idiopathic uveitis fit any of the gene expression patterns of the diagnosable systemic diseases.

They noted that the majority of idiopathic uveitis patients presumably are not diagnosed with any of the four associated systemic diseases, but they were still able to reclassify 11 of 38 subjects by gene expression profiling with 85% accuracy.

They concluded that peripheral blood gene expression profiling may be a potential adjunct for making differential diagnoses of uveitis, although further validation and research is necessary.

Rosenbaum JT, Harrington CA, Searles RP, et al. Revising the diagnosis of idiopathic uveitis by peripheral blood transcriptomics. Am J Ophthalmology. September 15, 2020. [Epub ahead of print].