A significant negative correlation was observed between all peptides originating from ALB (rho (range): -0.18 to -0.53, P < 0.05), A1BG (rho (range): -0.31 to -0.34, P < 0.05), AHSG (rho (range): -0.18 to -0.47, P < 0.05), APOA1 (rho (range): -0.38 to -0.52, P < 0.05), B2M (rho (range): -0.17 to -0.59, P < 0.05) and eGFR in CKD (S2 Table), whereas the same peptides were not correlated with eGFR in the controls (P > 0.05). This evidence concerns the gene B2M and chronic kidney disease.