[Measurement of the charge on red blood cells in patients with various glomerulopathies]

Red blood cells have a negative charge on their surface which prevents Rouloau formation. This charge may reflect the charge on glomerular capillaries. Using alcian blue, we measured the negative charge on red blood cells in patients with IgA nephropathy (IgAN), membranous nephropathy (MN), minimal change nephropathy (MCN) and focal glomerular sclerosis (FGS), for which the diagnosis was determined by renal biopsy. The alcian blue values for the normal control, IgAN, MCN (nephrotic phase), MCN (remission) and MN were 155.3 +/- 12.3, 140.9 +/- 23.9, 101.7 +/- 18.4, 152.9 +/- 11.2 and 140.9 +/- 23.6 ng per 1 x 10(6) red blood cells, respectively. The charge was more significantly decreased in MCN during nephrotic phase than other renal diseases and the normal control. The charge in MCN was within the normal range on remission. When we studied the correlation between the charge on red blood cells and proteinuria during steroid therapy, the charge in MCN was found to increase with reduction of proteinuria, while there was no change in MN and FGS with reduction of proteinuria, i.e. it was usually within normal range. The reduced charge was associated with the nephrotic phase in MCN. The difference in the charge on the red blood cells between MCN and FGS during nephrotic phase seems to suggest a different etiology of proteinuria. Measurement of the charge on red blood cells could be an useful method for differentiating MCN from other renal diseases in the nephrotic phase.