DIFFERENT ERYTHROCYTE AND PLATELET SURFACE ELECTRIC CHARGE IN VARIOUSTYPES OF GLOMERULONEPHRITIS

Background. Some preliminary observations suggest that predisposition to a particular type of glomerulonephritis (GN) may be connected with the genetically determined charge of the glomerular capillary wall. A correlation between erythrocyte surface and the glomerular capillary w all charges has also been observed. The purpose of this study was to v erify and extend previous investigations. Therefore we measured erythr ocyte and platelet surface charge from patients with idiopathic membra nous and mesangial GN as well as idiopathic membranoproliferative GN a nd lupus nephrits. Methods, The erythrocyte and platelet surface charg e was determined by the binding of the cationic dye, alcian blue (AB). A fresh alcoholic AB solution was made for each experiment, which wer e run in batches of four, each including cells from a healthy person a nd from patients each with a different type of GN. Results, In patient s with idiopathic membranous and membranoproliferative GN, a significa nt decrease in the erythrocyte and platelet charges was observed irres pective of their clinical state (remission or nephrotic syndrome). Ery throcyte charge was decreased despite the normal amount of membranous sialic acid. In contrast, patients with idiopathic mesangial GN, in co mplete or partial remission, exhibited normal erythrocyte and platelet surface charges. Exclusively in this type of GN, the appearance of ne phrotic proteinuria was associated with a slight decrease, the erythro cyte charge, which was not statistically significant (P>0.1). A reduct ion in the negative erythrocyte charge in lupus nephritis was less in magnitude than in idiopathic membranous or membranoproliferative GN, a nd occurred independently of the level of daily proteinuria, whereas t he platelet charge was normal. Conclusion, The decrease of the erythro cyte and platelet charge in idiopathic membranous and mebranoprolifera tive GN seems to be a pre-morbid feature.