Myeloid-related protein 8 expression on macrophages is a useful prognostic marker for renal dysfunction in children with MPGN type 1

Background: To clarify the role of subclasses of macrophages in chronic glomerulonephritis, we evaluated the relationship between myeloid-related protein 8 (MRP8) and MRP14 expression on macrophages and the progression of membranoproliferative glomerulonephritis (MPGN). Methods: We enrolled 35 patients with MPGN type 1 who had a normal creatinine clearance at the time of their first renal biopsy and divided them into 2 groups based on clinical status at the time of their most recent examination: 12 patients with normal urine test results and 12 patients with minor urinary abnormalities at the latest observation (group 1) and 7 patients with persistent nephropathy and 4 patients with renal insufficiency (group 2). The first and second renal biopsy findings and MRP8 and MRP14 expression on macrophages were investigated in both groups. Results: Mean scores for positive glomerular and interstitial MRP8 and CD68 staining at the time of the first and second biopsies were significantly higher in group 2 than group 1. At the time of the second biopsy, mean scores for interstitial CD68-positive (CD68 + ) staining were higher in group 2 than group 1. Mean scores for glomerular and interstitial MRP8 + and CD68 + staining at the time of the first biopsy correlated with the chronicity index at the time of second biopsy in both groups. Conclusion: Results suggest that MRP8 expression on macrophages in glomeruli and interstitial lesions at the first biopsy can be a useful prognostic marker for renal dysfunction in children with MPGN type 1.