Classify subtype, guide therapy, and monitor responses
The leading cause of nephrotic syndrome
Membranous nephropathy (MN) is one of the leading causes of nephrotic syndrome in adults. It is traditionally classified into primary and secondary membranous nephropathy. Cases without associated disorders are termed primary membranous nephropathy (PMN) while cases associated with other conditions, such as different autoimmune diseases, infectious or parasitic disease, tumor, or adverse reactions to certain medications, are referred to as secondary membranous nephropathy (SMN).
As more antigens that autoantibodies recognize are being identified, the distinction between PMN and SMN is becoming blurred. While certain target antigens are more strongly associated with specific secondary causes,1 other autoantibodies associated with the same antigen can be associated with both types. The variable and unpredictable natural course of MN and other associated diseases results in ongoing challenges for disease management.2
By the numbers
of patients with primary MN are positive for PLA2R
of patients with primary MN are positive for NELL-1
of patients with primary MN are positive for THSD7A
A distinct classification
Historically, autoantibodies against the podocyte protein M-type phospholipase A2 receptor (PLA2R) in the kidney have been determined as the major target antigen for patients with PMN.3 A 2014 study identified antithrombospondin type-1 domain-containing 7A (THSD7A) as another target antigen in ~1% of patients with PMN.4 More recently, Mayo Clinic researchers identified several additional antigens associated with MN, including neural epidermal growth factor-like 1 (NELL-1),5 exostosin1/2,6 semaphorin 3B (Sema3B),7 protocadherin 7 (PCDH7),8 and protocadherin FAT1 (FAT1).9
Testing improves patient outcomes
Extensive clinical, laboratory, and pathologic evaluation is required to accurately identify the underlying etiology of the different types of MN. Mayo Clinic Laboratories offers comprehensive renal testing services, concise results, and access to more than 150 years of advanced medical knowledge to deliver answers your practice needs to increase accuracy, improve outcomes, and keep care local.
Identify the antigen
Mayo Clinic Laboratories offers a comprehensive menu of clinically validated assays to assist with the diagnosis of PMN, monitor disease progression, and guide clinical outcomes.
A Test in Focus
John Lieske, M.D., describes Mayo Clinic Laboratories' new test for primary membranous nephropathy. PMND1 is a diagnostic cascade that provides a cost-effective approach to detecting antigens known to cause membranous nephropathy — a condition that can lead to kidney failure.
Confirm the causation
Mayo Clinic Laboratories offers a comprehensive menu of ancillary renal pathology tests to assist with the diagnosis of membranous nephropathy.
*Note: RPCWT automatically performs IF staining for PLA2R if MN is present (based on LM and IF). If PLA2R IF is negative, IF staining for THSD7A and IHC staining for NELL-1 will be performed.
A Test in Focus
Sanjeev Sethi, M.D., Ph.D., discusses how Mayo Clinic Laboratories’ new immunohistochemistry test for the detection of NELL-1 antigen, a biomarker for membranous nephropathy found in 10% to 15% of all MN patients, provides diagnostic certainty and insight on disease expression.