Figure 2.

Antibodies against anti-cyclic citrullinated peptides (aCCP) influence production of soluble PD-L1 (sPD-L1). (A) sPD-L1 in serum of aCCP+ and aCCP− RA patients, stratified by disease duration. Dots represent the median and whiskers represent the interquartile range. (B) sPD-L1 measured in lipopolysaccharide (LPS) stimulated cultures of peripheral blood monocytes from aCCP− healthy controls exposed to IgG of aCCP+ and aCCP− RA patients. The Mann–Whitney U test was applied. (C) Spearman’s rank correlation test between sPD-L1 in supernatant of healthy peripheral blood mononuclear cells cultures and aCCP content in serum of the patients from which the IgG was isolated. Cells were cultured with or without LPS stimulation. Circles represent median sPD-L1 level of each IgG sample (aCCP− n = 3, aCCP+ n = 4).