SPDL1 and chronic kidney disease: Median levels of sPD-L1 (pg/mL) showed an exponential increase with CKD stage progression, with levels from 77.0 (G1) and 80.7 (G2) in individuals without CKD, 84.7 (G3a), 105.0 (G3b), and 124.2 (G5) in patients with CKD, to 291.8 (G5d) in those undergoing dialysis (Figure 4A).