Yu X, et al. - Researchers sought to employ nano-HPLC-MS/MS analysis to evaluate serum biomarkers that predicted the clinical response to calcineurin inhibitors (CNI) therapy in primary membranous nephropathy (PMN) patients. Results demonstrated that a candidate PMN biomarker could be serum amyloid A1 protein (SAA1) that could be used to discriminate CNI no-remission (NR) cases from remission patients. The accuracy of diagnosis could be increased by the combination of SAA1 and the phospholipase A2 receptor (PLA2R) antibody.