Introduction: Few studies have reported the association between the complement cascade and pediatric immunoglobulin A nephropathy (IgAN). This study aimed to investigate the association between C4d staining positivity and the clinical/histopathological characteristics of pediatric patients with IgAN.
Methods: Children diagnosed with IgAN through renal biopsy were retrospectively reviewed. Renal biopsy specimens were stained using C4d immunohistochemistry.
Results: Among the 56 patients, 31 (55.4%) showed positive mesangial or peripheral capillary C4d staining in glomeruli. Urine protein-to-creatinine ratio was significantly higher in C4d-positive patients (p = 0.001). The severity of mesangial proliferation according to the Haas and Oxford classification was positively associated with positive C4d staining (p < 0.001).
Conclusion: Positive C4d staining was found to be significantly associated with the clinical/histopathological severity of IgAN.
Keywords: C4d; IgA nephropathy; children; mesangial proliferation; proteinuria.