[Urinary fibronectin excretion as a marker of disease activity in children with IgA nephropathy and Henoch-Schönlein nephropathy].

UNLABELLED: The increase of extracellular matrix proteins synthesis including fibronectin (FN) is associated with development of renal sclerosis. The aim of the study was to examine urinary FN excretion as a marker of renal changes in patients (pts) with IgAN and HSN. The study group consisted of 34 children: IgAN n=11 and HSN n=23, mean age 12.44 +/- 3.83 years. At the onset of illness we observed erytrocyturia in all children, proteinuria in 28: nephrotic sydrome in 14 pts (IgAN--4, HSN--10) and proteinuria in 14 children (IgAN--6, HSN--8). In mean time 0.6 years from the onset of illness renal biopsies were performed. Changes in light microscopy were graded I-V degrees according to the classification of WHO. FN was measured in 24-h urine collections (ng/mg of creatinine), using specific antibody (DAKO) and proteinuria (mg/24h). Mean time from the biopsies to examine FN was 0.76 +/- 1.16 years. FN excretion was analysed in 2 group pts: group A--with proteinuria (n=28); group B--with erytrocyturia (n=6). The control group (K) consisted of 14 healthy children. Renal function was normal in all.

RESULTS: The FN concentration higher than normal we observed in 22 pts (78.6%) in group A and 3 (50%) in group B. Mean FN value A was higher (NS) 274 +/- 213.0 than in B 132.0 +/- 68.8 and significant (p<0.01) than in group K (59.9 +/- 31.3). We found a positive correlation between FN and proteinuria in the moment of measurement the FN concentration (p=0.01, r=0.51). The higher values of FN (NS) we observed in pts with higher proteinuria at the onset of illness. FN excretion was significantly eleveted in younger children (p<0.001, r=-0,58). We not found a correlation between mean FN value and the grade of changes in renal biopsies (WHO).

CONCLUSION: Urinary FN excretion may be a marker of disease activity in children with IgAN and HSN.