Serum laminin P1 fragment concentration in renal diseases.

The serum concentration of laminin P1 fragment was determined in various histologically proven renal diseases by a competitive radioimmunoassay directed against the pepsin-resistant fragment P1. The serum laminin P1 fragment level of healthy subjects (n = 71) was 1.35 +/- 0.19 U/ml. Serum levels of laminin P1 fragment in patients with minimal change nephrosis in the remission phase and those with IgA nephropathy showed no significant difference when compared with healthy controls. However, patients with minimal change nephrosis in the nephrotic phase, membranous glomerulonephritis, diabetic nephropathy, lupus nephritis and renal cell carcinoma showed significantly higher levels (P less than 0.01) of serum laminin P1 fragment. No correlation was observed between serum laminin P1 fragment level and creatinine clearance. These results suggest that changes in serum laminin P1 fragment level could be used to indicate alterations in glomerular basement membrane metabolism in renal disease.