Molecular and spatial analysis unveils the functional basis of tertiary lymphoid structures in Sjogren’s syndrome[scRNA-seq]

The key role of tertiary lymphoid structures in autoimmune and non-autoimmune conditions has been recently appreciated. While many of the molecular mechanisms involved in tertiary lymphoid structure formation have been identified, their cellular sources and temporal and spatial relationship remain unknown. Using single-cell RNA-sequencing, spatial transcriptomics and proteomics of minor salivary glands of patients with Sjogren’s disease and Sicca Syndrome, ex-vivo and in vivo functional studies, we construct a cellular and spatial map of key components involved in the formation and function of tertiary lymphoid structures. We confirm the presence of a fibroblast cell state and identify an undescribed pericyte/mural cell state with potential immunological functions. The identification of novel cellular properties associated with these structures and the molecular and functional interactions identified by this analysis provide key therapeutic cues for tertiary lymphoid structures associated conditions in autoimmunity and cancer.