CD40LG and acute kidney injury: Postoperative peak titers of Ig M and Ig G were also significantly higher in the patients with AKI than those without AKI (Ig G: 1:64 [1:16 to 1:256] vs. 1:4 [negative to 1:32], p < 0.001; Ig M: 1:32 [1:8 to 1:64] vs. 1:4 [negative to 1:16], p < 0.001, respectively).