Clinical Significance of Serum Galactose-Deficient IgA1 Level in Children with IgA Nephropathy

Abstract EN

This study was aimed at investigating the clinical significance of serum galactose-deficient IgA1 (Gd-IgA1) levels measured by a novel lectin-independent enzyme-linked immunosorbent assay (ELISA) using an anti-Gd-IgA1 monoclonal antibody (KM55) as a disease-specific biomarker for IgA nephropathy (IgAN) in children.

Thirty-three children with IgAN, 40 with non-IgA glomerular diseases, and 38 age-matched healthy controls (HCs) were enrolled.

Serum Gd-IgA1 levels were quantified by ELISA using KM55.

Results were statistically compared with clinical features and pathological findings of IgAN.

Serum Gd-IgA1 levels were significantly elevated in children with IgAN compared with children with non-IgA glomerular diseases and HCs.

Serum Gd-IgA1 levels in children with IgAN were positively correlated with serum total IgA levels.

However, the serum Gd-IgA1/total IgA ratio (Gd-IgA1/IgA) was also significantly elevated in children with IgAN.

Serum Gd-IgA1 levels in children with IgAN increased in an age-dependent manner.

The cutoff value of serum Gd-IgA1 levels for differentiating IgAN from non-IgA glomerular diseases was 3236 in children<12 years and 5284 in children≥12 years, respectively.

In contrast, serum Gd-IgA1/IgA was age-independent.

The cutoff value of serum Gd-IgA1/IgA for differentiating IgAN from non-IgA glomerular diseases was 0.2401.

Serum Gd-IgA1 levels were negatively correlated with eGFR and positively correlated with mesangial IgA deposition.

In contrast, serum Gd-IgA1/IgA levels were not correlated with any clinical parameters of IgAN.

In conclusion, serum Gd-IgA1 levels were significantly elevated in children with IgAN.

However, those levels were age-dependent; therefore, serum Gd-IgA1 levels classified by age and/or serum Gd-IgA1/IgA might have diagnostic values in children with IgAN.