In contrast, ICOS upregulation correlates with disease activity in several inflammatory diseases [20–24], and in preliminary studies, the anti-ICOSL mAb prezalumab (AMG-557) demonstrated some beneficial activity on the arthritis of systemic lupus erythematosus (SLE) (NCT04058028 [25];), as well as on overall disease activity in Sjögren’s syndrome (SjS) (NCT02334306). Here, ICOSLG is linked to systemic lupus erythematosus.