The CSF in neurosarcoidosis contains consistent clonal expansion of CD8 T cells, but not CD4 T cells

The tissue-specific drivers of neurosarcoidosis remain poorly defined. To identify cerebrospinal fluid (CSF) specific, antigen-driven T and B cell responses, we performed single-cell RNA sequencing of CSF and blood cells from neurosarcoid participants coupled to T and B cell receptor sequencing. In contrast to pulmonary sarcoidosis, which is driven by CD4 T cells, we found CD8 T cell clonal expansion enriched in the neurosarcoid CSF. These CSF-enriched CD8 T cells were composed of two subsets with differential expression of EBI2, CXCR3, and CXCR4. Lastly, our data suggest that IFNγ signaling may distinguish neurosarcoidosis from other neurological disorders

Clinicomolecular Identification of Conserved and Individualized Features of Granulomatous Uveitis

Purpose: To identify molecular features that distinguish individuals with shared clinical features of granulomatous uveitis. Design: Cross-sectional observational study. Participants: Four eyes from patients with active granulomatous uveitis. Methods: We performed single-cell RNA sequencing with antigen-receptor sequence analysis to obtain an unbiased gene expression survey of ocular immune cells and to identify clonally expanded lymphocytes. Main Outcomes Measures: For each inflamed eye, we measured the proportion of distinct immune cell types, the amount of B- or T-cell clonal expansion, and the transcriptional profile of T and B cells. Results: Each individual showed robust clonal expansion arising from a single T- or B-cell lineage, suggesting distinct, antigen-driven pathogenic processes in each patient. This variability in clonal expansion was mirrored by individual variability in CD4 T-cell populations, whereas ocular CD8 T cells and B cells were more similar transcriptionally among patients. Finally, ocular B cells displayed evidence of class switching and plasmablast differentiation within the ocular microenvironment, providing additional support for antigen-driven immune responses in granulomatous uveitis. Conclusions: Collectively, our study identified both conserved and individualized features of granulomatous uveitis, illuminating parallel pathophysiologic mechanisms and suggesting that future personalized therapeutic approaches may be warranted