FC-ALPHA-R EXPRESSION ON POLYMORPHONUCLEAR LEUKOCYTE AND SUPEROXIDE GENERATION IN IGA NEPHROPATHY

Superoxide (O-2(-)) production and Fc alpha R antigen expression of ci rculating polymorphonuclear leukocytes (PMNL) isolated from patients w ith IgA nephropathy (IgAN) and non-IgA mesangial proliferative glomeru lonephritis (PGN) and healthy volunteers were investigated to establis h their biological importance in the immunopathogenesis of mesangial p roliferative glomerulonephritis. PMNL from both patient groups showed increased O-2(-) production when stimulated with N-formyl methionyl le ucyl phenylalanine (FMLP) and phorbol myristate acetate (PMA). The inc reased O-2(-) generation demonstrated a positive correlation with the degree or proteinuria. Aggregated IgA caused enhanced O-2(-) productio n only in patients with IgAN who also showed a significant correlation with proteinuria. Increased expression of Fc alpha R on circulating P MNL was observed in IgAN patients as determined by flow cytometric ana lysis. The amount of Fc alpha R on PMNL was positively correlated with O-2(-) generation triggered with IgA aggregates. These results sugges t that (1.) circulating PMNL may potentially be participating in the p athogenesis of glomerular injury in mesangial proliferative glomerulon ephritis, and (2.) IgA aggregates/immune complexes may contribute to t he immunopathogenesis of IgAN through augmenting the Fccu receptor-med iated generation of superoxide anion.