A correlation between immunoexpression of CD44, alpha-SMA and CD68+ cells in IgA-nephropathy and in mesangial proliferative IgA-negative glomerulonephritis.

Immunoperoxidase staining was carried out using monoclonal antibodies against CD44, alpha-smooth muscle actin and CD68 on renal biopsy specimens from patients with IgA nephropathy (IgAN, n = 16) and mesangial proliferative IgA-negative glomerulonephritis (MesProGN, n = 15). As a control 10 biopsy specimens of the kidneys removed because of trauma were used. The results showed increase in glomerular CD44+ cells and CD68+ cells in IgAN biopsies as compared with controls and MesProGN. The intensity of glomerular alpha-SMA was increased in IgAN and MesProGN as compared with controls, but no statistical differences were shown in glomerular expression of alpha-SMA between IgAN and MesProGN. In both study groups there were significant positive correlations between glomerular CD44+ cells and CD68+ cells, as well as the intensity of alpha-SMA immunostaining. The interstitial expression of CD44 and alpha-SMA in IgAN patients was significantly higher as compared with controls and MesProGN group, whereas the mean values of interstitial CD68+ cell did not differ significantly in these glomerulopathies. In both IgAN and MesProGN there were significant positive correlations between interstitial expression of CD44 and alpha-SMA, between intensity of CD44 immunostaining and CD68+ cells as well as interstitial volume. In conclusion, our study suggests possible role of CD44 interaction in macrophage recruitment and the development of interstitial fibrosis and glomerular sclerosis in both glomerulopathies.