EDITORIAL REVIEWThe importance of advanced cytometry in defining new immune cell types and functions relevant for the immunopathogenesis of HIV infectionAgrati, Chiaraa; De Biasi, Sarab,∗; Fidanza, Luciab; Gibellini, Larab,∗; Nasi, Milenab; Pinti, Marcellob; Cossarizza, Andreab,cAuthor Information aNational Institute for Infectious Diseases ‘Lazzaro Spallanzani’, Roma bUniversity of Modena and Reggio Emilia School of Medicine, Modena cNational Institute for Cardiovascular Research, Bologna, Italy. Correspondence to Andrea Cossarizza, University of Modena and Reggio Emilia School of Medicine, via Campi 287, Modena 41125, Italy. E-mail: [email protected], [email protected] Received 24 July, 2020 Accepted 28 July, 2020 AIDS: December 1, 2020 - Volume 34 - Issue 15 - p 2169-2185 doi: 10.1097/QAD.0000000000002675 Buy Metrics Abstract In the last years, novel, exciting immunological findings of interest for HIV research and treatment were identified thanks to different cytometric approaches. The analysis of the phenotypes and functionality of cells belonging to the immune system could clarify their role in the immunopathogenesis of HIV infection, and to elaborate key concepts, relevant in the treatment of this disease. Important discoveries have been made concerning cells that are important for protective immunity like lymphocytes that display polyfunctionality, resident memory T cells, innate lymphoid cells, to mention a few. The complex phenotype of myeloid-derived suppressor cells has been investigated, and relevant changes have been reported during chronic and primary HIV infection, in correlation with changes in CD4+ T-cell number, T-cell activation, and with advanced disease stage. The search for markers of HIV persistence present in latently infected cells, namely those molecules that are important for a functional or sterilizing cure, evidenced the role of follicular helper T cells, and opened a discussion on the meaning and use of different surface molecules not only in identifying such cells, but also in designing new strategies. Finally, advanced technologies based upon the simultaneous detection of HIV-RNA and proteins at the single cell level, as well as those based upon spectral cytometry or mass cytometry are now finding new actors and depicting a new scenario in the immunopathogenesis of the infection, that will allow to better design innovative therapies based upon novel drugs and vaccines. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.