Relationship between serum IgA/C3 ratio and severity of histological lesions using the Oxford classification in children with IgA nephropathy

Pediatr Nephrol. 2015 Jul;30(7):1113-20. doi: 10.1007/s00467-014-3024-z. Epub 2014 Dec 31.


Background: The aim of this study was to evaluate the usefulness of serum immunoglobulin A/complement factor 3 (IgA/C3) ratio for predicting histological severity of kidney lesions in children with IgA nephropathy (IgAN) based on World Health Organization (WHO) and the Oxford classification (OC).

Methods: We studied 89 children with IgAN with a mean age of 11.38 ± 4.1 years (range 2-18 years). Based on available medical records, we retrospectively evaluated clinical data, IgA/C3 ratio, and kidney biopsy findings using the five-grade WHO classification and the OC The mesangial hypercellularity (M), endocapillary hypercellularity (E), segmental sclerosis (S), tubular atrophy/interstitial fibrosis (T) (MEST) score (absent = 0, present = 1) calculated as the sum of M+E+S+T ranging from 0 to 4.

Results: Mean IgA/C3 ratio values were significantly higher (P < 0.05) in patients with M1, S1, and T1 compared with M0, S0, and T0, respectively (P < 0.05); there were no differences in the WHO classification. We found a significant positive correlation between the IgA/C3 ratio and proteinuria (r = 0.24) and determined optimal cutoff values of the IgA/C3 ratio, with a corresponding confidence interval for specific MEST scores.

Conclusions: The IgA/C3 ratio in children with IgAN may be a useful marker of the severity of lesions found in kidney biopsy as evaluated using the OC.

MeSH terms

  • Adolescent
  • Age of Onset
  • Atrophy
  • Biomarkers / analysis
  • Biopsy
  • Child
  • Child, Preschool
  • Complement C3 / analysis*
  • Female
  • Fibrosis
  • Glomerular Mesangium / pathology
  • Glomerulonephritis, IGA / blood
  • Glomerulonephritis, IGA / classification
  • Glomerulonephritis, IGA / pathology*
  • Glomerulosclerosis, Focal Segmental / pathology
  • Humans
  • Immunoglobulin A / blood*
  • Infant
  • Kidney / pathology
  • Male
  • Predictive Value of Tests
  • Proteinuria / metabolism
  • Risk Factors
  • Urine / cytology


  • Biomarkers
  • Complement C3
  • Immunoglobulin A