Abstract

BACKGROUND
IgA nephropathy after renal transplantation (post-transplant IgAN) may recapitulate the IgAN of native kidneys, however, little has been reported about the histologic characteristics. The aim of this study is to apply glomerular morphometry using an image analyser to examine the histologic characteristics of post-transplant IgAN.
METHODS
The outer margin of the glomerulus (Bowman's area, BA) and glomerular tuft area (GA) were traced manually. The measured area were automatically calculated by KS300 image analysis system (Kontron, Munchen, Germany). The mesangial area (MA) was calculated with a summing each manually traced mesangial area. The total number of glomerular (GC) and mesangial cells (MC) were counted. Eight cases of renal section obtained by nephrectomy due to renal cell carcinoma (normal control: N-CTRL) and nineteen cases of renal section obtained from post-transplantation patients without IgAN (transplantation control: Tx-CTRL) served as controls.
RESULTS
A total of 35 biopsies were finally selected for measurement. BA and GA of post-transplant IgAN were 1.6 and 1.4 times larger than the N-CTRL, respectively, and were not significantly different from Tx-CTRL. MA was 1.4 times significantly larger than that of the Tx-CTRL. As compared to that of the N-CTRL, it was 1.2 times larger, but this difference was not statistically significant. The GC and MC of post-transplant IgAN and the Tx-CTRL were significantly lower than the N-CTRL. There were no significant correlations between glomerular hypertrophy and duration after renal transplantation, mesangial changes, segmental sclerosis, or degree of renal cortical interstitial fibrosis in post-transplant IgAN.
CONCLUSIONS
Prominent glomerular hypertrophy and mesangial expansion suggest a hyperfiltration injury in post-transplant IgAN and a possible way to glomerulosclerosis.

• Keywords: Glomerulonephritis;IGA;Image analysis;Computer assisted;Hypertrophy;Mesangium;Glomerular Kidney transplantation