[Serum IgA-fibronectin complex in children with various renal diseases]

IgA-Fibronectin complex (IgA-FN) has been found in the circulation of patients with IgA nephropathy (IgAN). It has been suggested that circulating IgA-FN is related to IgA deposits in the mesangial area following mesangial matrix expansion in IgAN. We investigated serum IgA-FN in patients with various renal diseases, and examined the relationship between IgA-FN and the clinico-pathological findings. Serum IgA-FN level was measured by enzyme-linked immunosorbent assay (ELISA) in 35 patients with IgAN, 20 patients with Henoch-Schönlein purpura nephritis (HSPN), and other various renal diseases in children. IgA-FN in patients with IgAN was significantly higher than in healthy subjects and patients with minimal change nephrotic syndrome. However some patients with membranoproliferative glomerulonephritis and lupus nephritis had a high level of IgA-FN. The increase in IgA-FN was correlated with macroscopic hematuria and the degree of proteinuria and mesangial matrix expansion in IgAN. Thus, we concluded that the level of IgA-FN is associated with mesangial matrix expansion.