IgA nephropathy (IgAN) patients with high serum levels of galactose-deficient IgA1 (Gd-IgA1) have poor renal outcomes, researchers reported at the European Renal Association-European Dialysis and Transplant Association 54th Congress in Madrid, Spain.
Gd-IgA1 deposits in glomeruli trigger the inflammation and injury that purportedly lead to IgAN. If future research confirms its predictive power, Gd-IgA1 level may represent a useful biomarker for risk stratification.
Jürgen Floege, MD, of University Hospital, Rheinisch Westfälische Technische Hochschule Aachen in Aachen, Germany, and colleagues investigated serum Gd-IgA1 levels in a subset of 104 IgAN patients from the STOP-IgAN trial who failed to respond to supportive treatment (i.e., optimized antihypertensive and antiproteinuric medication) over 6 months. Among non-responders, the investigators found that Gd-IgA1 levels were higher in those who progressed to end-stage renal disease (ESRD), had a decline in eGFR to a level above 30 mL/min/1.73 m2, or failed to achieve full remission after 3 additional years of treatment (i.e., supportive care with or without immunosuppressive therapy). The team also found that average Gd-IgA1 levels were similar in responders and non-responders at baseline (1073 vs 1094 μg/mL, respectively).
According to logistic regression analysis, each 200 μg/mL increase in baseline Gd-IgA1 level correlated with 31% greater risk of ESRD. By contrast, total IgA levels were not predictive. The researchers adjusted their analyses for important confounders, including proteinuria at baseline, GFR, treatment, age, and sex.
“The findings suggest that patients with high Gd-IgA1 are high-risk patients, and that the pre-treatment Gd-IgA1 level might be a good biomarker to stratify those patients who are in need of more intense treatment,” Dr Floege stated in a news release. Currently, aggressive treatment involves immunosuppressive drugs.
1. Floege J, Rauen T, Eitner F, et al. Galactose-deficient IgA1 Levels Predict Renal Outcome in the Stop-IgAN Trial Cohort. Abstract 3409. ERA-EDTA Congress 2017.
2. Whom to treat – and not to treat – with immunosuppressive drugs? ERA-EDTA; June 4, 2017. [news release]