Test Catalog

Test ID: THSD7    
Thrombospondin Type-1 Domain-Containing 7A Antibodies, Serum

Useful For Suggests clinical disorders or settings where the test may be helpful

Distinguishing primary from secondary membranous nephropathy

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Recently, autoantibodies against phospholipase A2 receptor (PLA2R) in the kidney were determined to be the major target antigen for patients with idiopathic/primary membranous nephropathy (MN).(1) Approximately 70% of patients with primary MN circulate anti-PLA2R antibodies, and in the remaining 30% (who are PLA2R-negative), antithrombospondin type-1 domain-containing 7A (THSD7A) was shown to have approximately a 10% prevalence (or about 3% of all primary MN patients).(2) Mouse podocytes express THSD7A and introduction of anti-THSD7A autoantibodies induces MN in murine models. Mouse podocytes do not express PLA2R so exogenous administration of anti-PLA2R does not recapitulate membranous nephropathy in mice.(3) Additionally, THSD7A has been described as a potential tumor antigen and, thus, it has been suggested that THSD7A-positive patients merit a thorough cancer screening.(4)

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Negative

Interpretation Provides information to assist in interpretation of the test results

Therapy outcome can be monitored by measuring the antibody titer. A titer increase, decrease, or disappearance generally precedes a change in clinical status. Thus, the determination of the antibody titer has a high predictive value with respect to clinical remission, relapse, or risk assessment after kidney transplantation.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

This test should not be used as a stand-alone test but as an adjunct to other clinical information. A diagnosis of primary or secondary membranous nephropathy (MN) should not be made based on a single test result. The clinical symptoms, results on physical examination, and laboratory tests (eg, serological tests), when appropriate, should always be taken into account when considering the diagnosis of primary versus secondary MN.

 

Absence of circulating autoantibodies does not rule out a diagnosis of primary MN.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Beck LH Jr, Bonegio RG, Lambeau G, et al: M-type phospholipase A2 receptor as target antigen in idiopathic membranous nephropathy. N Engl J Med 2009;361:11-21. doi: 10.1056/NEJMoa0810457

2. Tomas NM, Beck LH Jr, Meyer-Schwesinger C, et al: Thrombospondin type-1 domain-containing 7A in idiopathic membranous nephropathy. N Engl J Med. 2014;371:2277-2287.doi: 10.1056/NEJMoa1409354

3. Tomas NM, Hoxha E, Reinicke AT, et al: Autoantibodies against thrombospondin type 1 domain-containing 7A induce membranous nephropathy. J Clin Invest. 2016;126(7):2519-2532. doi: 10.1172/JCI85265

4. Stahl PR, Hoxha E, Wiech T, et al: THSD7A expression in human cancer. Genes Chromosomes Cancer. 2017;56:314-327. doi: 10.1002/gcc.22440