Primary Sjögrens Syndrome (pSS) is an auto immune disease characterized by eye dryness (keratoconjunctivitis sicca) and a dry mouth (xerostomia), mainly caused by increased lymphocyte infiltration to the lacrimal and salivary glands. pSS primarily affects middle aged women and it has an estimated prevalence from 0.9–6 per 1000 of the general population. About a third of the cases develop more severe systemic symptoms while around 5% of the patients develop B-cell lymphomas. B-cells are central to the pathogenesis of pSS. Infiltrating subpopulations of B-cells are frequently observed in the salivary glands in patients and and autoantibodies for Sjögrens Syndrome Related antigen A and B (SSA and SSB) are found in 60–80% and 30–40% of the cases, respectively. Given the prominent role of B-cells in pSS onset and development we propose to investigate differences in B-cell compartment composition in patients with pSS by single-cell RNA sequencing of sorted primary B-cells from patients.