['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).', '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.', '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.'] Is myeloid-related protein 8 expression on macrophages a useful prognostic marker for renal dysfunction in children with MPGN type 1?