26604 Thrombospondin Type-1 Domain-Containing 7A Antibodies, Serum (THSD7)

​Anti-THSD7A; THSD7A; Thrombospondin​

​​Distinguishing primary from secondary membranous nephropathy cases with antibodies against THSD7A

​Centrifuge and aliquot serum into plastic vial within 2 hours of collection.

​Gross hemolysis

​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.

​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). Approximately 70% of patients with primary MN circulate anti-PLA2R antibodies, and in the remaining 30% (who are PLA2R-negative), anti-thrombospondin type-1 domain-containing 7A (THSD7A) was shown to have approximately a 10% prevalence (or about 3% of all primary MN patients). 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. 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.

​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.