1262 Fig. 3 Glomerular expression of components of the renin-angiotensin system (RAS) in the biopsies. Kidney sections were immunostained with either anti-angiotensin-converting enzyme antibody (a, b), anti- angiotensin II antibody (c, d) or anti-angiotensin II type 1 receptor antibody (e, f) in patients with minor glomerular abnormalities (MGA) (a, c, e) or immunoglobulin A nephropathy (IgAN) (b, d, f) (original magnification, ×200) 2.09) but not ACE (mean score 0.96) was significantly enhanced in the IgAN group compared with the MGA group (mean scores for AGT, ang II, ACE 0.93, 1.00, 0.50, respectively) (P < 0.01) (Fig. 4). The expression level of AT1R tended to be lower, but not statistically significant, in Pediatr Nephrol (2008) 23:1257–1267 patients with IgAN compared with the MGA group (mean score 1.63 in MGA vs 1.26 in IgAN). The expression of TGF-β and α-SM actin, potential factors associated with GN progression, was greatly enhanced in the expanded mesangial regions in patients with IgAN in contrast with patients with MGA (Fig. 5a–d). Semiquantitative analysis indicated that the levels of TGF- β and α-SM actin expression were significantly higher in the IgAN group than in the MGA group (mean score 0.50 and 0.63 in MGA vs 1.91 and 1.91 in IgAN; P < 0.01) (Fig. 5e). Correlation of RAS components with pathologic changes in patients with MGA or IgAN Possible relationships between glomerular RAS activation and injury in diseased kidney were investigated to examine the correlations between the expression of RAS components, ang II-inducible factors, TGF-β and α-SM actin histologic Fig. 4 Semiquantitative assessment of immunostaining of angiotensi- nogen (AGT), angiotensin-converting enzyme (ACE), angiotensin II (ang II) and ang II type 1 receptor (AT1R) in the kidney sections from patients with minor glomerular abnormalities (MGA) (□) or immuno- globulin A nephropathy (IgAN) (■). Data are means ± standard deviation. †P<0.01 vs MGA Fig. 5 Glomerular expression of transforming growth factor-β (TGF- β) and α-smooth-muscle (α-SM) actin in biopsies. Kidney sections were immunostained with either anti-TGF-β antibody (a, b) or α-SM actin (c, d) in patients with minor glomerular abnormalities (MGA) (a, c) or immunoglobulin A nephropathy (IgAN) (b, d) (original magnification ×200). Semiquantitative assessment of immunofluores- cence staining of TGF-β and α-SM actin immunostaining in patients with MGA (□) or IgAN (■). †P<0.01vs MGA