Dataset related to the article "Anti-nephrin antibodies are not enriched in patients with primary and post-transplant recurrent podocytopathies""

The .xlsx file contains raw data related to the article "Anti-nephrin antibodies are not enriched in patients with primary and post-transplant recurrent podocytopathies".

Abstract

Abstract

Background: Anti-nephrin autoantibodies have been suggested as a potential immunological driver in a subset of patients with podocytopathies, including minimal change disease and focal segmental glomerulosclerosis. Of clinical relevance, these autoantibodies have been proposed as novel predictors of post-transplant focal segmental glomerulosclerosis recurrence in most affected patients.

Methods: Here, we measured circulating anti-nephrin autoantibodies in a well-established cohort of 33 patients with post-transplant focal segmental glomerulosclerosis recurrence. Additionally, patients with steroid-sensitive nephrotic syndrome (n=40) and steroid-resistant nephrotic syndrome (n=26) were included. Thirteen patients with membranous nephropathy and 20 healthy volunteers served as controls. ELISA and immunoprecipitation assays were performed to detect anti-nephrin IgG using two different human nephrin recombinant proteins. Immunofluorescence analysis was performed to assess the deposition of IgG and their colocalization with nephrin in renal biopsies.

Results: When using murine antigen-based ELISA, the highest positivity was found in healthy volunteers (50%), correlating with levels of circulating natural α-galactose-α-1,3-galactose antibodies. This cross-reactivity was abrogated with recombinant human nephrin expressed in human cells. In this setting, one post-transplant recurrent FSGS patient tested positive (1/33; ~3%), a frequency comparable to healthy volunteers (1/20; ~5%). A similar frequency was found in steroid-sensitive and steroid-resistant nephrotic syndrome. These results were confirmed by immunoprecipitation. By confocal microscopy, only trace amounts of IgM, but no IgG, were found in the glomeruli in any of the biopsies analyzed. Super-resolution microscopy confirmed the absence of colocalization with IgM or IgG with nephrin.

Conclusions: With the methodology presented here, anti-nephrin reactivity is extremely rare and occurred at comparable low frequencies in healthy controls, post-transplant focal segmental glomerulosclerosis recurrence, and native-kidney nephrotic syndrome. This suggests that these autoantibodies are not inherently disease specific.