Analysis of infiltrating cells in IgA nephropathy with acute clinical onset

Abstract

Background. The prognosis of IgA nephropathy (IgAN) patients is worse than that of poststreptococcal acute glomerulonephritis (PSAGN) patients. Some IgAN patients with acute clinical onset exhibit severe glomerular inflammation similar to that seen in patients with PSAGN, although most IgAN has an insidious onset. The aim of this study was twofold: (1) to differentiate glomerular inflammatory responses between IgAN and PSAGN and (2) to differentiate IgAN by its clinical manifestations. Methods. We examined 31 IgAN patients; 10 with acute clinical onset (AIgAN), 6 with acute exacerbation associated with chronic IgAN (ACIgAN), 8 with insidious onset (IOIgAN), and 7 with acute clinical onset who were anti-streptolysin-O positive (ASLOIgAN). We also examined 11 patients with PSAGN. Conventional pathological examinations were done using immunohistopathologic evaluation of infiltrating cells. Results. (1) Injuries to the glomerular basement membrane (GBM) were common and more severe in AIgAN than in PSAGN. The number of activated monocytes/macrophages (BerMac-3) was significantly greater in the glomeruli of ASLOIgAN than in those of AIgAN (P < 0.05). The numbers of T cells (CD45RO), granulocytes (CD15), and myeloperoxidase (MPO)-positive cells were significantly greater in the glomeruli of PSAGN than those of AIgAN in the other two groups (P < 0.05). (2) In regard to clinical manifestations, injury to the glomerular basement membrane (GBM) was most severe in ACIgAN. The number of MPO-positive cells was significantly greater in the glomeruli of AIgAN than in those of ACIgAN or IOIgAN. Conclusion. In AIgAN, glomerular damage was accompanied by severe GBM injury, but this injury was unexplained by the analysis of cell subclasses, in contrast to findings in PSAGN. Regarding the clinical manifestations of IgANs, MPO-positive cells may play some role in the glomeruli of AIgAN.