<p>Granulomas are found in multiple infectious and non-infectious human diseases, yet the pathogenic drivers of granulomatous disease are still poorly understood. To enrich for pathologic inflammatory cells, we leveraged the intrinsic immunologic isolation of the eye by examining granulomatous uveitis, a form of ocular inflammation. We performed single-cell RNA-sequencing to obtain an unbiased gene expression survey of ocular immune cells in the anterior chamber of four live human donors with granulomatous uveitis. We paired this with antigen-receptor sequence analysis to identify clonally expanded lymphocytes. Each individual had robust clonal expansion arising from a single T or B cell lineage, suggesting distinct pathogenic processes in each patient. This variability in clonal expansion was mirrored by individualized combinations of TH1, TH1/TH17, and Tregs in ocular CD4 T cells. In contrast, ocular CD8 T cells were more transcriptionally similar across donors. Finally, clonally expanded, activated B cells displayed evidence of plasmablast differentiation and class-switching within the ocular microenvironment. Collectively, our study identified conserved and individualized features of granulomatous inflammation, illuminating parallel pathophysiologic mechanisms.</p>

Tissue and Fluid Analysis in Ocular Inflammatory Disease