Segmental glomerulosclerosis in IgA nephropathy after renal transplantation: relationship with proteinuria and therapeutic response to enalapril.
BACKGROUND
Although graft dysfunction has been increasingly reported in post-transplant IgA nephropathy (Tx-IgAN), intragraft morphological changes have been largely overlooked. We evaluated glomerular changes in Tx-IgAN to identify the histological features pertaining to significant proteinuria and therapeutic response to enalapril.


METHODS
Fifty-four renal allograft biopsies, diagnosed as Tx-IgAN at a median of 46 months after transplantation, were the subject of the study. In 10 patients, glomerular morphometry was performed. In 14 patients who have been treated with enalapril for more than 12 months, we correlated the therapeutic response to enalapril with allograft histology.


RESULTS
No uniform pattern was found in the glomeruli of Tx-IgAN. The glomerular mesangium was mostly indistinct. Interstitial fibrosis was negative or mild in 88.9%. By morphometry, the glomerular tuft areas and mesangial areas were significantly larger in Tx-IgAN than those of the normal native kidney (p < 0.05), but were not different from transplant cases without glomerulonephritis. Proteinuria of >/=1 g/24 h was correlated with glomerulosclerosis, interstitial fibrosis and interstitial inflammation at time of biopsy (p < 0.005). The presence of segmental sclerosis (SS) correlated well with the amount of 24-h proteinuria (p < 0.001). After treatment with enalapril, the amount of proteinuria reduced in 64.3%. Therapeutic response to enalapril tended to be less effective in patients having SS (28.6 versus 71.4%), but this finding did not reach a statistical significance.


CONCLUSIONS
Significant proteinuria was associated with advanced chronic injury, especially with the presence of SS in Tx-IgAN, but anti-proteinuric effect of enalapril was not affected by graft histology. It remains to be clarified whether glomerular mesangial expansion plays a role in graft dysfunction in a subset of Tx-IgAN showing prominent mesangial changes.
Jeong
Hyeon Joo
HJ
Departments of Pathology, Surgery, Internal Medicine, and BK21 Project for Medical Science, Yonsei University College of Medicine, Seoul, South Korea.
Kim
Yu Seun
YS
Kwon
Kye Won
KW
Kim
Myoung Soo
MS
Kim
Soon
S
Choi
Kyu Hun
KH
Lee
Ho Yung
HY
Han
Dae Suk
DS
Park
Kiil
K
D000328:Adult; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D001706:Biopsy; D016022:Case-Control Studies; D003404:Creatinine / Q000097:blood; D004656:Enalapril / Q000627:therapeutic use*; D005260:Female; D005922:Glomerulonephritis, IGA / Q000473:pathology*; D005923:Glomerulosclerosis, Focal Segmental / Q000473:pathology; D006801:Humans; D007678:Kidney Glomerulus / Q000473:pathology*; D016030:Kidney Transplantation / Q000473:pathology*; D008297:Male; D011507:Proteinuria / Q000188:drug therapy* / Q000473:pathology; D012189:Retrospective Studies
D000806:Angiotensin-Converting Enzyme Inhibitors; D004656:Enalapril; D003404:Creatinine