M-type phospholipase A2 receptor (PLA2R) antibody, IgG

The M-type phospholipase A2 receptor (PLA2R) antibody, IgG test (anti-PLA2R IgG; phospholipase A2 receptor antibody) assists in the differential diagnosis of nephrotic syndrome and glomerulonephritides. It is used to establish idiopathic membranous nephropathy, gauge prognosis, and track response to treatment. Anti-PLA2R IgG demonstrates high specificity for primary membranous nephropathy and helps distinguish primary disease from secondary membranous nephropathy and from other glomerular disorders.

Anti-PLA2R antibodies are directed against a transmembrane glycoprotein expressed on podocytes and are predominantly of the IgG4 subclass. They are present in approximately 52%–82% of idiopathic membranous nephropathy cases and are generally absent in secondary membranous nephropathy and in other glomerulopathies, including IgA nephropathy, focal segmental glomerulosclerosis, and minimal change disease, supporting high disease specificity. Higher anti-PLA2R titers associate with greater clinical activity and heavier proteinuria, a reduced chance of spontaneous remission, and a higher risk of relapse. With effective therapy, antibody concentrations typically fall and may become undetectable during clinical remission; rising titers can precede or coincide with relapse. Results should be interpreted alongside the clinical picture and, when indicated, renal biopsy findings, and do not replace a comprehensive evaluation to exclude secondary causes.