Kidney Week

Abstract: TH-PO0462

Increase in Serum Galactose-Deficient IgA1 Levels Measured by New Lectin Enzyme-Linked Immunosorbent Assay (ELISA) Predicts Progression to Kidney Failure in Adults with IgAN

Session Information

• Glomerular Diseases: Clinical, Outcomes, and Therapeutics Research - IgAN
  October 22, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics

Authors

• Julian, Bruce, Reliant Glycosciences, Birmingham, Alabama, United States

Bruce Julian, MD

• Placzek, William J., Reliant Glycosciences, Birmingham, Alabama, United States

William J. Placzek, PhD

• Helmuth, Margaret, University of Michigan Michigan Medicine, Ann Arbor, Michigan, United States

Margaret Helmuth, MA

• Larkina, Maria, University of Michigan Michigan Medicine, Ann Arbor, Michigan, United States

Maria Larkina, MS

• Renfrow, Matthew, Reliant Glycosciences, Birmingham, Alabama, United States

Matthew Renfrow, PhD

• Szul, Tomasz, Reliant Glycosciences, Birmingham, Alabama, United States

Tomasz Szul, PhD

• Novak, Jan, Reliant Glycosciences, Birmingham, Alabama, United States

Jan Novak, PhD

• Mariani, Laura H., University of Michigan Michigan Medicine, Ann Arbor, Michigan, United States

Laura H. Mariani, MD, MS, FASN

• Rizk, Dana V., Reliant Glycosciences, Birmingham, Alabama, United States

Dana V. Rizk, MD

Background

IgA nephropathy (IgAN) is the most common primary glomerular disease in many countries and a frequent cause of kidney failure. In its hypothesized autoimmune pathogenesis, circulatory galactose-deficient IgA1 (Gd-IgA1) is the autoantigen recognized by IgG autoantibodies to form circulating immune complexes, some of which deposit in the glomerular mesangium to induce injury. Elevated serum Gd-IgA1 levels, measured by lectin-based ELISA, have been associated with worse kidney outcomes, but use of different lectins and batch-to-batch variations in binding affinity and specificity limit reproducibility and cross-study comparability. We assessed whether serum Gd-IgA1 measured by a novel standardized lectin-based assay, GalD® Assay, predicts kidney outcomes in adults with IgAN.

Methods

Gd-IgA1 was measured in paired serum samples from 245 adults with biopsy-proven IgAN in the Cure Glomerulonephropathy Network (CureGN), a multicenter longitudinal cohort. Index samples were taken closest to the initial kidney biopsy; follow-up samples were obtained near 1 year later (5–20 months), with at least 5 months follow-up. Changes in Gd-IgA1 were correlated with changes in urine protein/creatinine ratio (UPCR) using Pearson correlation. Cox proportional hazards models evaluated kidney failure (defined as dialysis, transplantation, or two eGFRs <15 mL/min/1.73 m² ≥30 days apart) as a function of percent change in Gd-IgA1, adjusting for age, UPCR, eGFR, race, immunosuppression, RAAS inhibitor use, and time from biopsy to first sample.

Results

Median (IQR) follow-up after the first sample was 8.5 (6.5–9.4) years. Participants were 76% White, 55% male, and had a median age of 42 (31–55) years. Median eGFRs were 58 (42–86) and 57 (37–84) mL/min/1.73 m², with UPCRs 0.9 (0.2–1.7) and 0.6 (0.2–1.5) g/g at baseline and follow-up, respectively. Gd-IgA1 was measured 15.8 (5.0–37.8) months post-biopsy and 13.3 (10.7–15.2) months later. Levels changed by a median of 1.5% (−13.5% to 11.6%) and were weakly inversely correlated with UPCR change (r = −0.19, p = 0.003). In adjusted models, each 1% increase in Gd-IgA1 was associated with a 1.3% higher hazard of kidney failure (HR 1.013, 95% CI 1.004–1.022; p = 0.006).

Conclusion

Percent change in serum Gd-IgA1 measured by the GalD® Assay independently predicted kidney failure in adults with IgAN.

Funding

• NIDDK Support – Reliant Glycosciences