IMMUNOHISTOCHEMISTRY: THROMBOSPONDIN (THSD7A)

MEMBRANOUS GLOMERULOPATHY IS CHARACTERIZED BY SUBPEITHELIAL IMMUNE COMPLEXE DEPOSITS IN GLOMERULAR CAPILLARIES. AUTOANTIBODIES AGAINST PHOSPHOLIPASE A2 RECEPTOR (PLA2R) ARE THE MAJOR TARGET ANTIGEN FOR MOST PATIENTS (ABOUT 70%) WITH MEMBRANOUS NEPHROPATHY (MN).IN THE REMAINING 30% (WHO ARE PLA2R-NEGATIVE), ANTITHROMBOSPONDIN TYPE-1 DOMAIN-CONTAINING 7A (THSD7A) IS SHOWN TO HAVE APPROXIMATELY A 10% PREVALENCE (OR ABOUT 3% OF ALL PRIMARY MN PATIENTS), MAKING IT THE SECOND MOST COMMON TARGET FOR ANTIBODIES IN MGN. THSD7A WAS INITIALLY CHARACTERIZED AS AN ENDOTHELIAL PROTEIN THAT IS EXPRESSED IN THE PLACENTAL VASCULATURE. THSD7A IS CONCENTRATED AT THE BASAL ASPECT OF THE PODOCYTE, AND NOT EXPRESSED IN GLOMERULAR ENDOTHELIAL CELLS.