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Polymorphs infiltrate glomeruli in mesangial IgA glomerulonephritis
P Kincaid-Smith1, K Nicholls, I Birchall
1Department of Medicine, University of Melbourne, Victoria, Australia.
Abstract:
During episodes of macroscopic hematuria, patients with IgA nephropathy commonly have polymorphonuclear neutrophils (PMNs) as well as fibrin and mononuclear cells in glomerular capillaries. We quantitated PMN and macrophage infiltration in glomeruli of 54 patients with IgA nephropathy in whom renal biopsies were obtained within 30 days of macroscopic hematuria. Control biopsies (N = 22) were from patients with IgA nephropathy and urinary erythrocyte counts below 50,000/ml. PMN monocyte/macrophages were quantitated using the monoclonal antibodies FMC10 and HAM56, respectively. In patients with heavy hematuria, 45.9 +/- 3.4% (mean +/- SE) of glomeruli were positive for PMNs (control 10.5 +/- 2.8%, P = 0.001) with a mean PMN count/glomerulus of 1.10 +/- 0.20 (control 0.13 +/- 0.03, P = less than 0.001). 65.6 +/- 9.7%. Of the glomeruli were positive for monocytes in the heavy hematuria group (control 40.0 +/- 8.4, P less than 0.05) with the mean monocyte count per glomerulus being 1.6 +/- 0.2 (control 0.6 +/- 0.1, P less than 0.01). We conclude that, in the acute phase of mesangial IgA nephropathy, PMN and monocytes are present and presumably participate in glomerular injury.
Insights
During IgA nephropathy flares, polymorphonuclear neutrophils (PMNs) and monocytes infiltrate glomeruli. This study quantifies these immune cells, suggesting their role in acute glomerular injury during heavy hematuria episodes.
Area of Science:
- Nephrology
- Immunology
- Pathology
Background:
- IgA nephropathy (IgAN) is a common cause of glomerulonephritis.
- Macroscopic hematuria is a frequent clinical manifestation of IgAN flares.
- Glomerular infiltration by inflammatory cells is suspected in IgAN pathogenesis.
Purpose of the Study:
- To quantify polymorphonuclear neutrophil (PMN) and monocyte/macrophage infiltration in glomeruli during acute IgAN.
- To determine if increased immune cell presence correlates with heavy hematuria in IgAN patients.
Main Methods:
- Renal biopsies from 54 IgAN patients with macroscopic hematuria were analyzed.
- Control biopsies from 22 IgAN patients with microscopic hematuria were used.
- Monoclonal antibodies (FMC10 for PMNs, HAM56 for monocytes) quantified cell infiltration.
Main Results:
- Patients with heavy hematuria showed significantly higher glomerular PMN infiltration (45.9% vs 10.5%) compared to controls.
- Monocyte infiltration was also significantly elevated in heavy hematuria patients (65.6% vs 40.0%).
- Mean PMN and monocyte counts per glomerulus were substantially higher in the heavy hematuria group.
Conclusions:
- Polymorphonuclear neutrophils and monocytes are significantly increased in glomeruli during acute IgAN with heavy hematuria.
- These inflammatory cells are likely involved in the glomerular injury observed during IgAN flares.
- Findings support the role of innate immune cells in the acute phase of IgAN.