Novel lectin-independent approach to detect galactose-deficient IgA1 in IgA nephropathy

Nephrol Dial Transplant. 2015 Aug;30(8):1315-21. doi: 10.1093/ndt/gfv221. Epub 2015 Jun 23.


Background: Galactose-deficient IgA1 (Gd-IgA1) is a critical effector molecule in the pathogenesis of IgA nephropathy (IgAN). Although many researchers have measured serum levels of Gd-IgA1 using snail helix aspersa agglutinin (HAA) lectin-based assay, the lectin-dependent assay has some serious problems in robustness. In this study, we aimed to establish a more robust and stable enzyme-linked immunosorbent assay (ELISA) method that uses a specific monoclonal antibody to recognize a hinge region in human Gd-IgA1 (Gd-IgA1 ELISA).

Methods: Rats were immunized with human Gd-IgA1 hinge region peptide to obtain Gd-IgA1-specific monoclonal antibody KM55. Gd-IgA1 ELISA for specifically detecting serum Gd-IgA1 was consequently constructed. Serum Gd-IgA1 concentrations in human subjects were measured using KM55 ELISA assay. To further confirm specificity of the Gd-IgA1-specific antibody, KM55 was also applied for immunofluorescence staining of glomerular Gd-IgA1 in paraffin-embedded sections of renal biopsy specimens.

Results: Measurement of serum levels of Gd-IgA1 in human subjects by Gd-IgA1 ELISA revealed increased serum Gd-IgA1 level in patients with IgAN compared with patients with other renal diseases or non-renal diseases. Importantly, the results obtained from Gd-IgA1 ELISA positively correlated with those from the HAA lectin-based assay (R = 0.75). Immunofluorescence staining of renal biopsy specimens with KM55 detected glomerular co-localization of Gd-IgA1 and IgA.

Conclusion: This novel lectin-independent method with KM55 for measuring serum levels of Gd-IgA1 can pave the way for more convincing diagnosis and activity assessment of IgAN, and can expedite clinical research to better understand this difficult disease.

Keywords: ELISA; IgA nephropathy; galactose-deficient IgA1; helix aspersa agglutinin (HAA); immunofluorescence; monoclonal antibody.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Agglutinins / metabolism
  • Animals
  • Antibodies, Monoclonal
  • Biomarkers / blood*
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Fluorescent Antibody Technique
  • Galactose / deficiency*
  • Glomerulonephritis, IGA / blood
  • Glomerulonephritis, IGA / diagnosis*
  • Humans
  • Immunoglobulin A / blood*
  • Kidney Glomerulus / metabolism
  • Kidney Glomerulus / pathology*
  • Lectins / metabolism*
  • Rats
  • Rats, Sprague-Dawley


  • Agglutinins
  • Antibodies, Monoclonal
  • Biomarkers
  • Immunoglobulin A
  • Lectins
  • Galactose