Macrophage subclasses and proliferation in childhood IgA glomerulonephritis

We immunohistologically compared the number of intraglomerular infiltrating cells in 14 children with poststreptococcal acute glomerulonephritis (PSAG N) and 20 children with immunoglobulin A glomerulonephritis (IgAGN) with hi stological characteristics similar to those of PSAGN to explain the differe nce in clinicopathological characteristics between these two diseases. Immu nohistological study was performed in kidney tissues from these patients by using monoclonal antibodies of T-cell marker (CD3 and CD45RO), B-cell mark er (CD20), neutrophil marker (CD15), macrophage marker (CD68), four subclas ses of macrophages (early-stage, acute-stage, chronic-stage, and mature inf lammatory macrophage marker), and proliferating cell nuclear antigen (PCNA) . The 34 patients were classified into three stages according to the time f rom the detection of urinary abnormalities to biopsy. Intraglomerular immun opositive cells were expressed as the number of cells per glomerulus. There were more intraglomerular positive cells of CD15, CD68, and the four macro phage subclasses In PSAGN than IgAGN. The number of intraglomerular infiltr ating macrophages decreased with time in PSAGN, whereas the number of macro phages in IgAGN remained constant at all stages. Intraglomerular infiltrati on of acute-stage Inflammatory macrophages alone was evident in IgAGN. Both the number of intraglomerular proliferating macrophages (PCNA-positive plu s CD68-positive cells) and proportion of proliferating macrophages/total ma crophages were greater In IgAGN than PSAGN. Normal urinalysis results were evident in all patients with PSAGN during follow-up, and urinary abnormalit ies persisted in 18 patients with IgAGN. In conclusion, differences in the maturity of infiltrating macrophages and number of proliferating macrophage s are associated with the different clinicopathological characteristics in children with PSAGN and IgAGN. (C), 2001 by the National Kidney Foundation, Inc.