Sialic acid in childhood renal diseases: correlation with clinical and laboratory indices

There are many kinds of glycoproteins that have sialic acid residues and it has been reported that these are elevated in some renal diseases and their significance in the pathogenesis of several renal diseases has been investigated. In the present study the serum and urine levels of sialic acid were measured in healthy controls and in children with either poststreptococcal acute glomerulonephritis (PSAGN) or minimal change nephrotic syndrome (MCNS) to test if there is any correlation with clinical and laboratory indices. In PSAGN and MCNS patients the serum and urine sialic acid concentrations at onset and relapse were significantly different from healthy controls (Mann-Whitney U-test P < 0.005). There was not a significant correlation between the clinical severity, serum creatinine and complement C3 levels and serum sialic acid concentrations in PSAGN patients. Also there was not a significant correlation between edema, serum albumin, IgG, transferrin, alpha-1-antitrypsin and serum sialic acid concentrations in MCNS patients. Although high serum and urine sialic acid levels were found in both PSAGN and MCNS patients, it does not have any clinical significance nor is it important as a diagnostic or prognostic marker.