The overall concept of the HarmonicSS project is to bring together the largest well characterized regional, national and international longitudinal cohorts of patients with Primary Sjögren’s Syndrome (pSS) including those participating in clinical trials, and by taking into consideration the ethical, legal, privacy and IPR issues for sharing data from different countries, to semantically interlink and harmonize them into an integrative pSS cohort structure on the cloud. Upon this harmonized cohort, open services for big data mining, governance and visual analytics will be integrated, to address the identified clinical and health policy pSS unmet needs.