Changes in urinary and serum concentrations of macrophage-colony stimulating factor (M-CSF) in patients with renal diseases

Background. The infiltration of monocytes/macrophages into renal tissues is a typical feature of progressive renal diseases. Macrophage-colony stimulating factor (M-CSF) is one of the cytokines that are required for the activation of macrophages. It was previously reported that the glomerular expression of M-CSF was increased in patients with mesangial proliferative glomerulonephritis and that the urinary and serum M-CSF concentrations were increased in IgA nephropathy. In this study, we measured the urinary and serum M-CSF concentrations in patients with renal diseases to elucidate the role of M-CSF and macrophages in the progression of renal diseases. Methods. We examined urinary and serum M-CSF concentrations in patients with IgA nephropathy (IgA-N), lupus nephritis (LN), minimal change nephrotic syndrome (MCNS), and membranous nephropathy (MN), and in normal controls. The M-CSF concentrations were compared with the clinical parameters and the histological changes. These concentrations were also compared with the number of glomerular macrophages in the IgA-N group. In addition, the effects of prednisolone therapy on the M-CSF concentrations were examined in the patients with IgA-N. Results. Urinary and serum M-CSF concentrations were increased in the severe IgA-N group, the severe LN group, and the MCNS group (nephrotic) compared with concentrations in the control group. Urinary and serum M-CSF concentrations were correlated with the degree of proteinuria, mesangial proliferation, and the number of glomerular macrophages in IgA-N and LN. In addition, the urinary and serum M-CSF concentrations were decreased with prednisolone therapy in the patients with IgA-N. Conclusions. Urinary and serum M-CSF concentrations were elevated in patients with severe stage of mesangial proliferative glomerulonephritis and were correlated with the amount of urinary protein excretion, mesangial proliferation, and glomerular macrophage infiltration. Urinary and serum M-CSF concentrations may be useful markers with which to assess the extent of glomerular changes in mesangial proliferative glomerulonephritis.