Published October 28, 2022 | Version v1
Journal article Open

Identification and characterization of circulating immune complexes in IgA nephropathy

Description

The underlying pathology of immunoglobulin A (IgA) nephropathy (IgAN), the most common glomerulonephritis worldwide, is driven by the deposition of immune complexes containing galactose-deficient IgA1 [Tn(+)IgA1] in the glomerular mesangium. Here, we report that novel anti-Tn circulating immune complexes (anti-Tn CICs) contain predominantly IgM, representing large macromolecular complexes of ~1.2 megadaltons to several megadalton sizes together with Tn(+)IgA1 and some IgG. These complexes are significantly elevated in sera of patients with IgAN, which contains higher levels of complement C3, compared to healthy individuals. Anti-Tn CICs are bioactive and induce specific proliferation of human renal mesangial cells. We found that these anti-Tn CICs can be dissociated with small glycomimetic compounds, which mimic the Tn antigen of Tn(+)IgA1, releasing IgA1 from anti-Tn CICs. This glycomimetic compound can also significantly inhibit the proliferative activity of anti-Tn CICs of patients with IgAN. These findings could enhance both the diagnosis of IgAN and its treatment, as specific drug treatments are now unavailable.

Data availability

All data needed to evaluate the conclusions in the paper are present in the paper and/or Supplementary Materials with no restrictions. The DiαGalNAc can be provided by E.L.C. pending scientific review and a completed material transfer agreement. Requests for the DiαGalNAc should be submitted to echaikof@bidmc.harvard.edu.

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Additional details

Identifiers

DOI
10.1126/sciadv.abm8783
Other
oai:uchicago.tind.io:10917

Funding

National Institute of General Medical Sciences
P41GM103694
National Institute of General Medical Sciences
R24GM137763
National Institute of Diabetes and Digestive and Kidney Diseases
R01DK080876

UChicago Information

Division(s)
Biological Sciences Division, Pritzker School of Medicine
Department(s)
Medicine