Characterization of THSD7A-antibodies not binding to glomerular THSD7A in a patient with diabetes mellitus but no membranous nephropathy

© 2021. The Author(s)..

Membranous nephropathy (MN) is an autoimmune disease caused by autoantibodies against the podocyte antigens phospholipase A2 receptor 1 (PLA2R1) and thrombospondin type 1 domain containing protein 7A (THSD7A) in 80% and 2-3% of patients, respectively. THSD7A antibodies are considered to be pathogenic and highly specific for MN patients. Using an indirect immunofluorescence test (IIFT) we detected THSD7A-antibodies (titre 1:10) in the serum of a patient with high proteinuria who, however, in the kidney biopsy was diagnosed with diabetic nephropathy and MN was excluded as a possible cause of proteinuria. Different immunofluorescence assays and Western blot techniques using recombinant THSD7A (rTHSD7A) or THSD7A from different human tissues revealed that the circulating THSD7A-autoantibodies were only of the IgG3 subclass. The patient serum reacted exclusively with rTHSD7A and only when the antigen was present in reducing Western blot conditions, or on formaldehyde-fixed cells for the IIFT. Our findings show for the first time the existence of circulating THSD7A-antibodies recognizing denatured/reduced rTHSD7A, which do not react with glomerular THSD7A in vivo and are thus presumptively non-pathogenic. As a consequence, kidney biopsy or Western blot analyses of THSD7A under non-reducing conditions should be performed to confirm the diagnosis of THSD7A-associated MN, especially in cases with low THSD7A-antibody levels in the IIFT.

Medienart:

E-Artikel

Erscheinungsjahr:

2021

Erschienen:

2021

Enthalten in:

Zur Gesamtaufnahme - volume:11

Enthalten in:

Scientific reports - 11(2021), 1 vom: 10. Aug., Seite 16188

Sprache:

Englisch

Beteiligte Personen:

Reinhard, Linda [VerfasserIn]
Thomas, Cindy [VerfasserIn]
Machalitza, Maya [VerfasserIn]
Lattwein, Erik [VerfasserIn]
Weiss, Lothar S [VerfasserIn]
Vitu, Jan [VerfasserIn]
Wiech, Thorsten [VerfasserIn]
Stahl, Rolf A K [VerfasserIn]
Hoxha, Elion [VerfasserIn]

Links:

Volltext

Themen:

Autoantibodies
Case Reports
Journal Article
Research Support, Non-U.S. Gov't
THSD7A protein, human
Thrombospondins

Anmerkungen:

Date Completed 08.11.2021

Date Revised 08.11.2021

published: Electronic

Citation Status MEDLINE

doi:

10.1038/s41598-021-94921-y

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM329206702