Treatment of subclinical injuries detected by protocol biopsy improves the long-term kidney allograft function: a single center prospective randomized clinical trial

BACKGROUND

The long-term benefit of early treatment of subclinical disorders detected in kidney allografts by protocol biopsy is controversial. We collected 145 protocol biopsies from 113 recipients for comparison with 51 control patients in a single-center, prospective, randomized trial.

METHODS

Ultrasound-guided biopsies were performed in recipients with stable renal function. Samples were taken at 3 (n=66) and/or 12 months (n=79) after transplantation. The biopsies were evaluated according to the Banff scheme, and patients were treated based on the diagnosis. Changes in glomerular filtration rate (GFR) were compared with 51 patients who were randomized as a control group.

RESULTS

The findings on 38 samples (29%) were considered to be normal. Based on the pathology findings, such as subclinical acute rejection (n=23), calcineurin inhibitor toxicity (n=28), chronic rejection (n=6), and other specific pathologies (n=23), including polyoma virus nephropathy (n=2), induced treatment among 82 recipients (57%). Significantly better graft function was observed at 3-year follow-up among the biopsy group, compared with controls: GFR = 46.0 ± 13.8 vs 35 ± 15 mL/min (P=.002). The 5-year graft survival was significantly higher in the biopsy (81%) than in the control (55.6%) group (P=.0012).

CONCLUSION

Early detection and treatment of subclinical pathologies improved graft function and long-term survival. Protocol biopsies were a valuable tool for posttransplantation management.

Peritubular capillary damage in acute humoral rejection: an ultrastructural study on human renal allografts

The ultrastructural features of peritubular capillary (PC) damage was studied in 12 kidney allografts with acute humoral rejection (AHR). AHR manifested in diffuse linear PC staining for C4d, and histology consistent with Banff grade III in 7 recipients and Banff grade II in 5. Allografts with acute tubular necrosis served as controls. First biopsies (post-transplantation day 16.2 +/- 2.2): The intra-capillary exudate comprised monocytes (59%), polymorphonuclears (14%), lymphocytes (12%) and not otherwise specified mononuclears (15%). Three patterns of focal PC endothelial injury were observed: lysis, an increased rate of apoptosis and fragmentation. No correlation was found between the respective damage types and the inflammatory cell types or the Banff grades. Controls revealed endothelial swelling, detachment from basement membrane and fragmentation. Follow-up biopsies: Monocytes transformed into macrophages intra-luminally. The reparative changes comprised endothelial cytoplasmic protrusions, binucleated endothelial cells and capillary sprouts. Early transplant capillaropathy and transplant glomerulopathy were noted in 2 recipients. Literature data indicate that lysis is mediated by anti-HLA alloantibodies; apoptosis, demonstrated first in the present study, may be induced by non-HLA-type anti-endothelial antibodies. Fragmentation is caused by ischemia. Ongoing endothelial injury leads to transplant capillaropathy and transplant glomerulopathy, the characteristic lesions of chronic rejection.

The value of electron microscopy in the diagnosis of chronic renal allograft rejection

The main causes of the late dysfunction of renal allografts are chronic rejection and chronic transplant nephropathy. Both are clinicopathologic entities, with a similar clinical presentation, but different histologic appearances. Chronic rejection is characterized by the presence of alloantigen-induced lesions (transplant arteriopathy and transplant glomerulopathy), and chronic transplant nephropathy by nonspecific sclerosing changes. The incidence of transplant arteriopathy and transplant glomerulopathy is relatively low. Electron microscopy (EM) may overcome the limitations in the histologic diagnosis of chronic rejection, because it verifies alloantigen-induced chronic microvasculopathy in the peritubular capillaries (transplant capillaropathy), and identifies transplant glomerulopathy more precisely than does light microscopy. To assess the value of EM in chronic rejection diagnosis, a retrospective search for transplant capillaropathy and transplant glomerulopathy was performed in a consecutive series of 91 biopsies performed > or = 6 months after implantation (median: 26 months, range 6-186) and the diagnoses were reclassified on the basis of the ultrastructural findings. The definitions used were: transplant capillaropathy: a peritubular capillary profile with seven or more circumferential basement membrane layers, or at least three profiles with five or six circumferential layers; ultrastructurally verified transplant glomerulopathy: thickening of the capillary wall in at least three loops in consequence of the widening of the subendothelial space by abnormal basement membrane material, and the formation of a new layer(s) of basal lamina; and chronic rejection: the presence of transplant capillaropathy and/or transplant glomerulopathy and/or transplant arteriopathy. Histologically, chronic transplant nephropathy, chronic rejection, chronic cyclosporine nephrotoxicity, glomerulonephritis, acute rejection, "suspicious" for acute rejection, and "others" were diagnosed in 37%, 34%, 21%, 19%, 57%, 30%, and 5% of the specimens, respectively. The results of EM increased the diagnosis of chronic rejection to 69% of the cases, and decreased chronic transplant nephropathy to 15%. The individual incidence of transplant capillaropathy and transplant glomerulopathy was 79% and 57%, respectively, and their cumulative incidence was 92%. Five biopsies exhibited merely transplant arteriopathy. A late dysfunction typically had more than one cause; the most frequent combination was chronic rejection and acute rejection. In conclusion, the EM search for transplant capillaropathy and transplant glomerulopathy doubled the frequency of the diagnosis of chronic rejection. Currently, the evaluation of renal allograft biopsies from recipients with a late dysfunction relies on standard light microscopy. Because light microscopy per se proved to be insensitive in the diagnosis of chronic rejection, incorporation of EM into the evaluation of late dysfunction biopsies is strongly recommended.

Ureter diverticulum of transplanted kidney. Case report

OBJECTIVES

Authors present a case of successful surgical treatment of a ureter diverticulum observed 3 months after kidney transplantation.

METHODS

The fluid collection was detected by ultrasound. Percutaneous drainage was performed, after that the excretion of 4 litres of fluid was observed during 12 hours. This finding clearly indicated the connection with the urinary system. This fact was proved and precisely localised by contrast filling of the lesion under fluoroscopic control.

RESULTS

Resection of the ureter diverticulum was performed, and the patient recovered fully, there was no change observed in the graft function during the whole procedure.

CONCLUSION

The ureter diverticulum is a rare complication after kidney transplantation: the present case is the only one observed among more then 600 kidney transplantations performed during 20 years in our centre.

[The role of ultrasonography and biopsy following kidney transplantation]

Several complications can occur during both the early and late postoperative periods after kidney transplantation. The methods used to follow up 575 kidney transplanted patients, (transplantations performed between October 1979 and November 1997) in the early (within 6 weeks) and late postoperative periods have been assessed. The diagnostic value of core biopsies and ultrasound examinations, the prevalence of complications, and the applicability of the diagnostic tools in the evaluation of the graft status and viability were analyzed. In the early postoperative period, graft rupture occurred more frequently after biopsy than in the late period (7.4% vs 0.82%), this leading graft loss in 18 of 20 cases. The sonographically diagnosed morphologic and functional changes were also analyzed. Sonography proved a very accurate method for the detection of perirenal fluid collections and masses and severe vascular complications. The data demonstrated that biopsy is indicated in the early postoperative period when the result of sonography is doubtful. In the late postoperative period, biopsy should be performed in every case.

[Comparative analysis of ultrasonic studies, histopathological data and clinical parameters in dysfunctioning renal transplantation]

The correlation of B mode and Doppler sonographic parameters and diagnoses established by histological examination of graft biopsies, nephrectomies and clinical data are discussed. 48 histological samples from 36 patients were reevaluated. The maximum interval between sonography and histology was 36 hours. The Banff classification criteria were used during histological examinations. Doppler examination evaluation was based on the resistance index (RI). Reproducibility was controlled by means of intra- and interobserver variability in 10 patients. RI values higher than 75% were regarded as abnormal. On the basis of these observations and the literature data specific sonographic features can be detected in renal artery occlusion and renal vein thrombosis. In pyelonephritis, dilatation of the collecting system was frequent. No morphological changes were detected in cyclosporin-A nephrotoxicity and the Doppler signs were not characteristic for this disease. No differentiation was found between acute rejection and acute tubular necrosis. The noninvasive duplex sonographic examinations can provide very important information regarding the flow situation of a transplanted kidney. In some cases a definitive diagnosis can be achieved, but in other cases biopsy is the method of choice.

[Recurrence of focal sclerosing glomerulonephritis in the kidney graft]

This is the first report on the recurrence of a glomerular disease in renal transplant in Hungary. The primary disease of the girl died at the age of 13 was focal sclerosing glomerulonephritis with slight mesangial cell proliferation. The first symptoms appeared at the age of 6.5 and they progressed rapidly. Four years later, because of the severe nephrotic syndrome and chronic renal failure, renal transplantation was performed with the synchronous removal of the patient's own kidneys. In the latter an interesting immunohistological finding has been observed: beside the usual positivities, the basement membrane of the distal tubule at the opposite side of the macula densa showed a strong reaction with anti IgM and a somewhat weaker positivity with anti C3 sera. The primary disease recurred very soon. A mesangial cell proliferation, however did not develop, in contrary to the primary disease, which contradicts the theory that the mesangioproliferative form would be a distinct clinicopathological entity.