AUTHOR=Castellano Eva , Samba Célia , Esteso Gloria , Simpson Laura , Vendrame Elena , García‐Cuesta Eva M. , López‐Cobo Sheila , Álvarez-Maestro Mario , Linares Ana , Leibar Asier , Ranganath Thanmayi , Reyburn Hugh T. , Martínez‐Piñeiro Luis , Blish Catherine , Valés‐Gómez Mar 

TITLE=CyTOF analysis identifies unusual immune cells in urine of BCG-treated bladder cancer patients

JOURNAL=Frontiers in Immunology

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2022.970931

DOI=10.3389/fimmu.2022.970931

ISSN=1664-3224

ABSTRACT=High grade non-muscle-invasive bladder tumours are treated with transurethral resection followed by recurrent intravesical instillations of Bacillus Calmette Guérin (BCG). Although bladder cancer patients respond well to BCG, important questions remain unanswered, including how to identify at early stages non-responder patients and patients at risk to abandon the treatment. Here, we analysed the cells released into the urine of bladder cancer patients longitudinally 3-7 days after BCG instillations. Mass cytometry (CyTOF) analyses revealed a large proportion of granulocytes and monocytes, mostly expressing activation markers. A novel population of CD15+CD66b+CD14+ CD16+ cells was very abundant in several samples and expression of these markers was confirmed using flow cytometry and qPCR. Samples of patients with a stronger inflammatory response contained more cells in urine; however, this was not due to haematuria, as the proportions of the cell populations observed were different from blood. This study shows that analysis of cells recruited to urine during treatment could help classify patients and identify those at risk of BCG infection and other unwanted BCG-related events, using conventional techniques, in larger cohort of patients.