ICOSLG and rheumatoid arthritis: ICOSL and its importance in antibody-mediated disease have also been verified in several preclinical models of human disease including RA, SLE, and uveitis [32, 36, 42–46] as well as in other models of arthritis (proteoglycan-induced arthritis (PGIA) and glucose-6-phosphate isomerase- (G6PI) induced arthritis), exemplifying the utility of anti-ICOSL-binding domains in the treatment of this immune disorder [44, 47, 48].