B2M and chronic kidney disease: Similar to the available evidence from patients with non-transplant CKD, serum β2M-based eGFR (<30 vs. >60 ml/min) has been found to predict CV events [HR: 2.56 (95% CI: 1.35–4.88; P = 0.004)], overall mortality [HR: 4.09 (95% CI: 2.21–7.54; P < 0.001)], and dialysis dependent kidney failure [HR: 15.53 (95% CI: 6.99–34.51; P < 0.001)] in allograft recipients (258).