Abstract
We used immunohistochemistry to study glomerular expression of the proliferation-associated antigen Ki-67 and α-smooth muscle actin (αSMA) in kidney biopsies from IgA nephropathy (IgAN), a type of proliferative glomerulonephritis. The non-proliferative glomerular disease, diabetic glomerulosclerosis (DGS) and idiopathic membranous nephropathy (MN) were also examined. Quantitative evaluation of the immunostaining results showed a significant increase in the number of Ki-67-positive (Ki-67+) cells in IgAN as compared to both DGS and MN, while glomerular αSMA expression was significantly higher in DGS and IgAN compared to MN. There was a significantly positive correlation between the number of Ki-67+ cells and αSMA expression in the glomerulus in IgAN ; however, there was no correlation between the expression of these factors in DGS or MN. Furthermore, in IgAN, the number of Ki-67+ cells in the glomerulus was significantly correlated to both urinary protein excretion and serum creatinine levels, but there was no relationship between the glomerular expression of αSMA and these clinical features. In addition, neither DGS nor MN exhibited a correlation between the number of Ki-67+ cells or αSMA expression and clinical findings. The estimation of urinary protein excretion is one of the most important laboratory measures for human glomerular diseases. Therefore, using Ki-67 expression to evaluate the proliferative activity of mesangial cells in renal biopsies may be useful for evaluation of both disease severity and activity in IgA nephropathy.
