Raised concentrations of the carboxy terminal propeptide of type IV (basement membrane) procollagen (NC1) in serum and urine of patients with glomerulonephritis

Type IV collagen is a major component of the glomerular and tubular basement membrane. We used a specific radioimmunoassay to determine (mean +/- SD) the concentration of carboxy terminal non-collagenous fragment (NC1) of type IV procollagen in the serum (normal 6.0 +/- 1.2 ng ml-1) and urine (normal 1.5 +/- 2.0 ng ml-1) of 142 patients with various kidney diseases. The 15 patients with active glomerulonephritis displayed (ANOVA, Scheffé test) significantly elevated NCl values in their serum (14 +/- 8.2 ng ml-1) as compared with the 32 patients with chronic interstitial nephritis (7.8 +/- 3.0 ng ml-1), the 17 patients with various other chronic kidney diseases (8.1 +/- 2.4 ng ml-1) and the 23 ambulatory kidney transplant patients (9.1 +/- 1.7 ng ml-1). The highest serum NCl concentrations were found in nine patients with membranoproliferative glomerulonephritis (16 +/- 9.4 ng ml-1). Sequential serum NCl concentrations in the one patient with active Goodpasture's syndrome were marginally elevated (less than 11 ng ml-1). Serum NCl did not increase with acute interstitial rejection episodes in six kidney transplant patients. The highest urinary NCl concentrations were found in seven patients with minimal change glomerulonephritis (7.5 +/- 3.2 ng ml-1). No correlation was found between serum NCl and serum creatinine, NCl and creatinine clearance, or renal NCl clearance and creatinine clearance. There was a significant correlation between serum NCl and proteinuria. Serum and urinary NCl concentrations were elevated independently from renal function, thus indicating intrinsic renal disease.(ABSTRACT TRUNCATED AT 250 WORDS)