A clinicopathological study of IgA nephropathy in renal transplant recipients: beneficial effect of angiotensin-converting enzyme inhibitor.
BACKGROUND
Prolonging the survival of transplant kidneys is a major task of modern nephrology. It has recently been shown that deteriorating renal function and substantial graft loss were observed in 55% of renal allograft recipients with recurrent IgA nephropathy (IgAN) at long-term follow-up. To gain a useful insight into the therapeutic approach towards protecting allograft kidneys from deteriorating graft function, we compared the histological characteristics of post-transplant IgAN to primary IgAN and investigated the effects of an ACE inhibitor.


METHODS
Twenty-one patients with post-transplant IgAN and 63 patients with primary IgAN were included in the histopathological study. The effectiveness of angiotensin-converting enzyme (ACE) inhibitor treatment in post-transplant IgAN was also studied in 10 patients.


RESULTS
The prevalence of glomeruli with adhesions and/or cellular crescents in primary IgAN was significantly greater than in post-transplant IgAN (P<0.05), but the proportion of glomeruli with segmental sclerosis was similar in both groups. The rate of global obsolescence, and the degree of interstitial fibrosis in post-transplant IgAN were significantly greater than in primary IgAN (P<0.05). The degree of glomerular obsolescence and the severity of interstitial fibrosis correlated with the severity of glomerular lesion in primary IgAN, but not in post-transplant IgAN. In primary IgAN, glomerular diameter significantly correlated with the proportions of glomerular obsolescence, but not in post-transplant IgAN, suggesting that allograft kidneys may be in a hyperfiltration state. Both the blood pressure and the urinary protein excretion significantly improved after ACE-inhibitor treatment (P<0.001).


CONCLUSIONS
In post-transplant IgAN, histopathological lesions indicative of acute inflammatory insults were suppressed, and glomerular hypertrophy, which may relate to haemodynamic burden such as hyperfiltration, was prominent. Preliminary study of ACE-inhibitor treatment in 10 patients showed favourable effects. A future long-term follow-up study is required to establish the effectiveness of ACE inhibitors in treatment of post-transplant IgAN.
Oka
K
K
Departments of Internal Medicine and Therapeutics and Urology, Osaka University Graduate School of Medicine, Sakurabashi Circulate Organ Clinic, School of Health and Sport Sciences, Osaka University, Osaka, Japan.
Imai
E
E
Moriyama
T
T
Akagi
Y
Y
Ando
A
A
Hori
M
M
Okuyama
A
A
Toki
K
K
Kyo
M
M
Kokado
Y
Y
Takahara
S
S
D000328:Adult; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D005260:Female; D005355:Fibrosis; D005922:Glomerulonephritis, IGA / Q000188:drug therapy* / Q000209:etiology / Q000473:pathology / Q000503:physiopathology*; D006801:Humans; D006973:Hypertension / Q000188:drug therapy / Q000209:etiology; D007211:Indoles / Q000627:therapeutic use*; D007668:Kidney / Q000473:pathology; D007678:Kidney Glomerulus / Q000473:pathology; D016030:Kidney Transplantation; D008297:Male; D011183:Postoperative Complications; D011507:Proteinuria / Q000188:drug therapy / Q000209:etiology; D012598:Sclerosis
D000806:Angiotensin-Converting Enzyme Inhibitors; D007211:Indoles; C052035:trandolapril