Immunophenotyping As a New Tool for Classification and Monitoring of Systemic Autoimmune Diseases

The clinical course of systemic autoimmune diseases (SADs) varies greatly, even between individuals with the same disease. Understanding of the immune actors is informative and could lead to significant improvements in diagnosis, monitoring, initial treatment decisions and/or follow-up. However, immunological changes in mononuclear cells associated with SADs have been only partially described, and usually are limited to analysis of peripheral blood cells (less than 5% of the total mononuclear pool). Another limitation is technological, related to utilization of flow cytometry, which remains highly variable with regards to sample preparation, reagents, instrument constraints, and data analysis. As a consequence, and although confirmation conducted by independent teams using multivariate analysis is lacking for proposing to use immunophenotyping in the diagnosis and/or follow-up of patients, there is a consensus of interest for monitoring several mononuclear cell subsets for emerging roles in SADs including memory B cells, effector T cells, and dendritic cells. In the near future and with the development of next generation technologies and standardized operating procedures, it is predicted that flow cytometry will find its place in the development of future personalized medicine in SADs. In addition, better understanding of immunological deregulations (e.g., intracellular phosphoproteins and cytokines, calcium actors) in both human and SAD-prone mouse models, as presented in this special issue, would undoubtedly open new perspectives and applications.