A morphometric insight into glomerular and interstitial lesions in acutely rejected renal allografts.

Twenty-four renal allograft biopsy specimens from patients with acute renal transplant rejection (ARTR) for whom both light and electron microscopy as well as immunofluorescence microscopy and full clinical data were available were examined quantitatively. The specimens had similar histologic Banff 97 (IA and IB) scores. As a control 10 biopsy specimens of the kidneys removed because of trauma were used. Morphometric investigations were performed by means of a computer image analysis system to evaluate glomerular and interstitial lesions in ARTR. Another purpose of our study was to ascertain the possible relationships between alpha-smooth muscle actin (alpha-SMA) expression and selected morphometric parameters as well as monocyte/macrophage count. Our study revealed that the mean values of total glomerular cells per total glomerular area, mesangium (% of total glomerular area), glomerular and interstitial alpha-SMA staining, glomerular and interstitial monocytes/macrophages as well as interstitial volume were increased in ARTR in comparison with controls. In ARTR group significant positive correlations existed between glomerular expression of alpha-SMA and total glomerular cells per total glomerular area, as well as glomerular CD68+ cells. Moreover, interstitial expression of alpha-SMA and interstitial volume, as well as interstitial CD68+ cells were in ARTR patients also positively and significantly correlated. Similarly, in this group positive significant correlation between interstitial volume and interstitial CD 68+ cells was noted. In conclusion, our study suggests that glomerular hypercellularity and mesangial changes are common in ARTR, whereas enhanced interstitial fibrosis confirms a risk of early allograft injury in these cases.