Proteinuria in cyclosporine-treated renal transplant recipients

Of 704 renal transplant recipients receiving long-term cyclosporine immunosuppression, 71 patients experienced proteinuria greater than 1 g/24 hr beyond the first month posttransplant. Eight patients displayed transient proteinuria, defined as lasting less than 3 months. In most cases this condition was attributed to biopsy-proved acute rejection. The transient proteinuria cohort experienced good graft outcome--namely, 87.5% one-year and 52.5% five-year actuarial graft survivals, which was similar to that observed in patients without proteinuria. In contrast, 52.4% of the 63 patients with nontransient proteinuria experienced graft loss within a median time of 6.1 months. The one- and five-year actuarial graft survivals in patients with nontransient proteinuria were 75.3% and 37.5%, respectively. Among the 63 patients with nontransient proteinuria, histopathologic diagnosis included chronic rejection in 19, transplant glomerulopathy in 14, acute rejection in 9, glomerulonephritis (GN) in 7 including 2 cases of membranous GN, and nonspecific interstitial fibrosis in 10 cases. Despite the overall poor prognosis for graft survival among the entire cohort of patients with nontransient proteinuria, the seven with allograft GN maintained prolonged graft function. They showed an 83.3% five-year actuarial graft survival versus 31.2% in patients with other causes of proteinuria (P = 0.043). These results suggest that posttransplant proteinuria in CsA-treated renal transplant recipients arises primarily as a consequence of allograft rejection and portends a poor graft outcome.     

Long-term beneficial effect of tacrolimus conversion on renal transplant recipients

OBJECTIVE: Acute rejection, chronic allograft nephropathy, and cyclosporine (CsA) toxicity remain serious problems for renal transplant recipients and may lead to graft loss. We retrospectively analyzed 34 patients whose biopsies revealed acute and/or chronic allograft rejection, or CsA nephrotoxicity, and who converted from CsA to tacrolimus. PATIENTS AND METHODS: From July 1996 through September 2003, CsA was converted to tacrolimus in 34 renal transplant recipients (26 male, 8 female) with renal biopsy at our hospital. Blood pressure and serum creatinine levels were checked monthly and serum cholesterol, triglyceride, and glutamic-pyruvic transaminase (GPT) levels were checked every three months. RESULTS: A consistently stable and better function after conversion was obtained in a significant portion (24, 71%) of patients. A statistically significant decline in serum creatinine and an improvement in the glomerular filtration rate were found at 3 m, 6 m, 12 m, 36 m, and 72 m after tacrolimus conversion. In 85.7% (12/14) of patients with acute rejection and in 35.7% (5/14) of patients with chronic allograft nephropathy (concomitant with acute rejection in 5), improved or stabilized graft function was noted. In addition, the systolic blood pressure and diastolic BP dropped significantly (P<0.05), while there was no significant change in cholesterol, triglyceride, and GPT levels. CONCLUSION: The beneficial effect of tacrolimus conversion on patients with acute rejection, chronic allograft nephropathy, or CsA nephrotoxicity was demonstrated in long-term follow up. The improvement in both renal function and blood pressure may be of paramount importance in reducing long-term cardiovascular morbidity and mortality.     

Use of candesartan cilexetil decreases proteinuria in renal transplant patients with chronic allograft dysfunction

BACKGROUND: Posttransplant proteinuria and hypertension are difficult to treat after renal transplantation. Therefore, we examined whether candesartan cilexetil is effective in reducing urinary protein excretion or in controlling hypertension in patients with renal allograft dysfunction. METHODS: Sixty-two renal transplant recipients with proteinuria were enrolled in this study. They underwent kidney transplantation under cyclosporine or tacrolimus immunosuppression between February 1983 and December 1998. Causes of proteinuria were chronic rejection in 28, glomerulonephritis in 16, cyclosporine or tacrolimus nephrotoxicity in 9, and unknown in 9 recipients. The dose of candesartan cilexetil ranged from 4 to 12 mg/day. Eleven patients with proteinuria who had not been treated with candesartan cilexetil constituted a matched control population. RESULTS: Hypertension was well controlled by administration of candesartan cilexetil. Both systolic blood pressure and diastolic blood pressure significantly decreased from 141.7+/-14.8 mm Hg to 118.7+/-11.9 mm Hg and 121.2+/-11.6 mm Hg, and from 89.0+/-13.0 mm Hg to 72.0+/-10.4 mm Hg and 74.9+/-9.4 mm Hg, at 2 months and 1 year after administration, respectively. Urinary protein excretion was reduced from 0.93+/-1.2 g/day to 0.34+/-0.7 g/day and 0.43+/-1.2 g/day at 2 months and 1 year after administration, respectively. The levels of creatinine clearance were 55.7+/-28.9 mL/min before treatment, 50.9+/-24.8 mL/min at 2 months, and 52.6+/-24.8 mL/min at 1 year after treatment, respectively. There was no clinically significant difference between them. Regarding the calcineurin inhibitor levels, there was no significant difference between the levels before and 1 year after treatment. There was a significant difference in all examinations (systolic blood pressure, diastolic blood pressure, proteinuria, and renal function) between the patients with and without candesartan at 1 year after treatment. No significant adverse effects occurred. CONCLUSIONS: Candesartan cilexetil can effectively control hypertension and proteinuria without deterioration in renal allograft function. These data suggest that treatment with candesartan cilexetil may be useful for maintaining long-term renal allograft function.     

Conversion from a calcineurin inhibitor-based immunosuppressive regimen to everolimus in renal transplant recipients: effect on renal function and proteinuria

New immunosuppressive agents are being actively researched to avoid complications of chronic allograft nephropathy (CAN), calcineurin inhibitor (CNI) nephrotoxicity, and posttransplantation cancer. The family of mTOR inhibitors offers a unique immunosuppressive opportunity to avoid CNI toxicity and reduce the incidence of malignancy. Nevertheless, increasing data have demonstrated that sirolimus (SRL), the first mTOR introduced in the treatment of solid organ transplant recipients, induces proteinuria, an adverse event that could produce deterioration of long-term renal function. In this short-term study of patients followed for 1 to 16 months, we examined changes in renal function and proteinuria among renal transplant recipients converted from a CNI-based regimen to an everolimus (EVL)-based one, a recently introduced mTOR inhibitor. Our data showed that renal function can be optimized after conversion to EVL by up to 42% in recipients showing CAN grade 1 or 2, or CNI nephrotoxicity. Importantly, patients who improved their creatinine clearance did not show increased proteinuria measured in a voided specimen as the ratio of urinary protein and creatinine concentration (P/C). These results, if confirmed with long-term follow-up and a larger number of patients, would allow us to consider EVL as a promising agent for maintenance immunosuppressive regimens in kidney transplantation.     

Glomerular pathology of allograft kidneys in Hong Kong

AIMS: Our goal was to define the spectrum of glomerular diseases in allograft kidneys and to correlate them with clinical parameters. METHODS: Eight hundred ninety-one renal graft biopsies and 43 graft nephrectomies from 1980 to 2004 were obtained from 442 allografts transplanted to 425 patients. RESULTS: Glomerular diseases were diagnosed in 33% of kidney grafts. Indications for biopsy were baseline assessment (23 biopsies, 2.5%); renal dysfunction (790 biopsies, 88.7%); proteinuria (154 biopsies, 17.3%); hematuria (11 biopsies, 1.2%); and study protocol (four biopsies, 0.4%). The median time to take a biopsy was less than 8 months posttransplant. The mean time posttransplant when the biopsy diagnosis was made was 70 months for IgA nephropathy (IgAN); 66 months for transplant glomerulopathy (TG); 65 months for focal segmental glomerulosclerosis (FSG); 55 months for mesangiocapillary glomerulonephritis (MCGN); 45 months for membranous glomerulonephritis (GN); 49 months for mesangial proliferative GN; and 101 months for diabetic nephropathy. Recurrent glomerular disease was documented in 31 (7.0%) grafts. Specific glomerular diseases were diagnosed by biopsies in 106 (89.1%) of 119 proteinuric allografts. CONCLUSIONS: Glomerulopathy was common in allografted kidneys. IgAN, TG, FSG, mesangial proliferative GN, and membranous GN were the majority. A higher proportion of grafts from donors related to the recipients than from unrelated donors showed IgAN (P < .05), suggesting that genetic factors might play a role in the pathogenesis of IgAN. Recurrence of glomerulopathy underlying ESRD was frequent for IgAN, FSG, and MCGN, but this was rarely seen in membranous GN.     

Clinical experience of mycophenolate mofetil in the treatment of chronic allograft nephropathy in kidney transplantation: three-year follow-up

BACKGROUND: Mycophenolate mofetil (MMF) in conjunction with calcineura antagonists has been shown to prevent acute rejection in renal allograft recipients. Its role in treatment of chronic rejection or allograft nephropathy is still controversial. We initiated the study to investigate the effect of adding MMF to a cyclosporine plus prednisolone regimen in renal recipients with chronic allograft nephropathy. MATERIALS AND METHODS: We retrospectively studied 36 patients with chronic allograft nephropathy, defined clinically as increased of serum creatinine, proteinuria, and hypertension. Renal function, cyclosporine level, renal biopsy, and renal scan were regularly done as indicated. MMF was added to 20 recipients after initial treatment with cyclosporine and prednisolone. The other 16 recipients were managed without adding MMF. Serum creatinine was monitored for 3 years. RESULTS: The demographic characteristics of the patients in the two groups were comparable. The average dose of prednisolone was unchanged throughout the study and the trough level of cyclosporine was maintained in the range of 100 to 150 ng/mL. The serum creatinine decreased initially in the group on MMF, but renal function deteriorated progressively after 6 months. There was a difference in serum creatinine between the two groups but this did not reach statistical significance. CONCLUSION: MMF therapy tender to improve renal function initially but did not attenuate significantly the impairment in chronic allograft nephropathy.     

Glomerulonephritis in renal allografts: results of 18 years of transplantations

The analysis of 1282 renal transplantations revealed 13 cases of allograft glomerulonephritis (GN). Membranous GN was detected in seven patients, and mesangiocapillary GN type 1, IgA GN and focal segmental glomerulosclerosis in two patients each. The transplantation material included 13 patients with post-transplant nephrotic syndrome (NS), in 9 of whom it was evidently caused by GN. NS was the most common clinical sign of allograft GN. In addition, one patient developed low-grade proteinuria and one hematuria. In one case no signs of GN were detected at the time of graft biopsy. Loss of allograft function was associated with additional severe rejection changes. Five patients are living with a functioning graft, four have been started on hemodialysis and four have died form non-renal causes. It is concluded that NS is rare after renal transplantation and that it is most often caused by allograft GN. The prognosis of the graft is determined by co-existing rejection.     

Longitudinal analysis of chronic allograft nephropathy: clinicopathologic correlations

BACKGROUND: Loss of the allograft from chronic allograft nephropathy and death of the patient from vascular, malignant, or infective disease are the major problems in renal transplantation today. Protocol biopsy of the long-term kidney has provided new data with which to develop strategies for prevention and treatment of chronic allograft nephropathy. METHODS: Two series of long-term protocol biopsies are reviewed. In the first, renal biopsies were obtained at time 0, and at 3 months and 12 months, and the recipients of the renal allografts were followed up for up to 15 years. In the second, the kidneys of recipients of simultaneous pancreas kidney transplants were biopsied annually for 10 years, and the results correlated with clinical events. RESULTS: Chronic allograft nephropathy is caused by acute and chronic immune-mediated damage, as well as by chronic calcineurin inhibitor nephrotoxicity. Both immune and nonimmune mechanisms exacerbate pre-existing donor disease and ischemia-reperfusion injury. Established interstitial fibrosis and arteriolar hyalinosis lead to progressive glomerular sclerosis and eventual loss of the graft. CONCLUSION: Protocol biopsies have shown that clinical parameters of renal function underestimate the severity of chronic graft damage. Strategies for preventing or treating chronic renal allograft dysfunction and subsequent graft loss must better control rejection and simultaneously avoid nephrotoxicity.     

Risk factors and prognosis for proteinuria in renal transplant recipients

INTRODUCTION: Proteinuria in renal transplant recipients has been recognized as a risk factor of progression of chronic allograft nephropathy and for cardiovascular disease, the main causes of transplant failure. PATIENTS AND METHODS: We analyzed the risk factors for persistent proteinuria (>0.5 g/day) among 337 kidney allograft recipients with a minimum follow-up of 6 months, among a series of 375 transplants performed during a decade, as well as their association with allograft and patient survivals. Patients with proteinuria greater than 0.5 g/d were treated with angiotensin-converting enzyme inhibitors (ACEI) and/or angiotensin-receptor blockers. RESULTS: After a mean follow-up of 53.35 +/- 52.63 months, 68 patients (20.17%) had persistent proteinuria greater than 0.5 g/d. Female patients (P = .012), body mass index (BMI) >25 (P = .008), pretransplant HLA sensitization (P = .039), and delayed graft function (DGF; P = .001) were associated with proteinuria. Induction treatment with antithymocyte globulin (P = .030) and treatment with tacrolimus instead of cyclosporine (P = .046) were associated with an increased risk of proteinuria. Multivariate analysis confirmed the independent value of DGF (RR = 2.23; 95% confidence interval [CI] 1.22 to 4.07; P = .009) and BMI >25 (RR = 1.968; 95% CI 1.05 to 3.68; P = .035) to predict postransplant proteinuria. The mean values of serum creatinine (P = .000) and systolic blood pressure (P < .05) were persistently higher from the early stages after transplantation in the proteinuric group. Graft survival at 5 years was 69% among patients who developed proteinuria and 93% in those without proteinuria (P = .000), with no differences in patient survival (P = .062). CONCLUSION: Proteinuria in renal transplant recipients was related to immunological and nonimmunological factors, some of which, such as hypertension and obesity could be modifiable. Proteinuria in renal transplant recipients predicted a worse allograft survival despite of intensive treatment of hypertension including ACEI/angiotensin-receptor blockers.     

IgA nephropathy in a patient with polycythemia vera. Clinical manifestation of chronic renal failure and heavy proteinuria

IgA nephropathy (IgAN) is one of the most frequent forms of glomerulonephritis (GN). However, its association with polycythemia vera (PV) has rarely been described. We report a case of IgAN combined with PV. The patient was a 46-year-old male with chronic renal failure, heavy proteinuria and erythrocytosis. He also presented hypertension and hematuria as well as splenomegaly, high arterial oxygen saturation and elevated leukocyte alkaline phosphatase activity. Possible causes of secondary erythrocytosis were ruled out. The renal biopsy revealed mesangial proliferative GN with predominant IgA deposition in mesangium. He was diagnosed as having IgAN and PV concomitantly. After administration of hydroxyurea, enalapril and felodipine, blood cell count and blood pressure normalized, while azotemia persisted. There was also a partial remission of the heavy proteinuria. We describe a case of IgAN associated with PV, and possible pathophysiologic relationships between two diseases are discussed with review of the literature.     

Long-Term Beneficial Effect of Tacrolimus Conversion on Renal Transplant Recipients

Objective. Acute rejection, chronic allograft nephropathy, and cyclosporine (CsA) toxicity remain serious problems for renal transplant recipients and may lead to graft loss. We retrospectively analyzed 34 patients whose biopsies revealed acute and/or chronic allograft rejection, or CsA nephrotoxicity, and who converted from CsA to tacrolimus. Patients and Methods. From July 1996 through September 2003, CsA was converted to tacrolimus in 34 renal transplant recipients (26 male, 8 female) with renal biopsy at our hospital. Blood pressure and serum creatinine levels were checked monthly and serum cholesterol, triglyceride, and glutamic-pyruvic transaminase (GPT) levels were checked every three months. Results. A consistently stable and better function after conversion was obtained in a significant portion (24, 71%) of patients. A statistically significant decline in serum creatinine and an improvement in the glomerular filtration rate were found at 3 m, 6 m, 12 m, 36 m, and 72 m after tacrolimus conversion. In 85.7% (12/14) of patients with acute rejection and in 35.7% (5/14) of patients with chronic allograft nephropathy (concomitant with acute rejection in 5), improved or stabilized graft function was noted. In addition, the systolic blood pressure and diastolic BP dropped significantly (P< 0.05), while there was no significant change in cholesterol, triglyceride, and GPT levels. Conclusion. The beneficial effect of tacrolimus conversion on patients with acute rejection, chronic allograft nephropathy, or CsA nephrotoxicity was demonstrated in long-term follow up. The improvement in both renal function and blood pressure may be of paramount importance in reducing long-term cardiovascular morbidity and mortality.     

移植肾IgA肾病三例报告及文献复习

目的 探讨移植肾IgA肾病的病理特征、临床表现及预后。方法 回顾分析移植肾穿刺活检病理及临床资料。结果 3例IgA肾病,1例为复发性膜增殖型,2例为复发／发性系膜增殖型,临床表现主要是镜下血尿、轻度蛋白尿、或／和高血压、高脂血症;病理改变与普通人群的IgA肾病相同,此外存在多灶性肾小管萎缩及间质纤维化;其对治疗的反应与病理改变密切相关,以双嘧达莫、小剂量华法林及雷公藤多甙治疗2年,2例系膜增殖型者肾功能稳定,膜增殖型的1例治疗2年半后血肌酐上升。结论 移植肾IgA肾病复发迅速,其进展速度及治疗效果与病理分型和病变程度密切相关,无特效治疗方法。     

Characteristics of long-term live-donor renal allograft survivors

BACKGROUND/AIMS: Despite the high rate of rejection, allograft failure and patient mortality in the early years of renal allotransplantation, some patients have done-remarkably well. We report here on 62 renal transplant recipients out of 144 patients (43%) who had functioning grafts for more than 15 years (range 15-24 years). MATERIALS: Demographic and follow-up data for patients fulfilling the criteria were reviewed. These patients include 43 males and 19 females, with a mean age at transplantation of 27.5 +/- 6.6 years (range 9-43 years), and mean donor age of 30 +/- 8.6 years. The donor source was 8 parents, 49 siblings and 5 unrelated. The main causes of end-stage renal disease were chronic pyelonephritis and chronic glomerulonephritis. Twenty-nine patients were treated with cyclosporine (CsA) while 33 patients were primarily immunosuppressed by steroids and azathioprine. RESULTS: Acute rejection episodes occurred in 40 patients (64.3%), out of them 19 patients experienced two or more acute rejection episodes. Univariate analysis showed that recipient and donor age, HLA-DR matching, pre- and post-transplant hypertension, ATN, delayed diuresis and chronic allograft nephropathy are significant risk factors; while recipient age, delayed diuresis and post-transplant hypertension were still significant by multivariate analysis. CONCLUSIONS: We concluded that renal transplantation, even in its earliest years and despite the numerous complications, has provided 15 or more years of near-normal life to patients with end-stage renal disease. Certain characteristics of long-term renal allograft survivors include young donor/recipient pairs, good DR matching with less pre- and post-transplantation prevalence of hypertension.     

肾移植受者蛋白尿病因分析及临床处理

目的探讨肾移植受者蛋白尿的病因和临床对策。方法对广州医学院第二附属医院2006年7月至2010年8月随访中出现蛋白尿的103例肾移植受者进行移植肾穿刺活组织检查（简称活检）,根据病理学诊断进行相应的临床治疗。结果 103例移植肾活检中急性排斥反应32例,慢性排斥反应25例,肾小球肾炎30例（其中IgA肾病12例）,肾小管-间质损伤7例,其他9例（包括肾小球轻微病变6例,糖尿病肾损害3例）。经过分类治疗后70.9%（73/103）受者蛋白尿逆转,肾功能维持稳定。结论排斥反应和原有肾疾病复发是导致肾移植受者蛋白尿的主要原因,移植肾活检是早期明确蛋白尿病因的有效手段,根据病理学诊断结果进行分类治疗可取得良好临床效果。     

Benefits of early biopsy on the outcome of kidney transplantation

INTRODUCTION: Delayed graft function has been associated with worse long-term kidney allograft survival. Adequate diagnosis of the etiology of dysfunction is crucial, often requiring routine early biopsies. The aim of this article was to report the results and safety of early kidney allograft biopsies and how they influenced its management. METHOD: Between September 1994 and July 2004, 134 renal transplant recipients were prescribed cyclosporine (CsA; Neoral, Novartis, Chile), steroids, and a third agent (azathioprine in 92% of the graft recipients). Thirty-four patients (26%) had a kidney biopsy performed within the first week because of allograft dysfunction. RESULTS: The main diagnosis was acute tubular necrosis (ATN) in 22 patients (65%), whereas 6 (18%) were diagnosed with an acute rejection episode (ARE), allowing prompt initiation of therapy with reversal of rejection in 4 of them. Two patients (6%) showed signs of thrombotic microangiopathy (TMA) induced by CsA, which subsided following a switch from CsA to tacrolimus (Prograf Pharmainvesti, Chile). In 2 patients, the biopsy specimen showed signs of CsA nephrotoxicity that reverted following dose reduction. Finally, in 2 patients, the biopsy specimen showed chronic nephropathy of donor origin, which had not been previously recognized, resulting in graft loss. There was only one major complication related to the biopsy, intraperitoneal bleeding that required surgical treatment. CONCLUSIONS: Early allograft biopsy is safe and, in a significant number of cases (30%), it detects important allograft pathology (ARE, TMA, and drug toxicity), which when adequately and promptly treated may rescue the graft.     

肾移植术后急性体液性排斥反应的治疗

目的 总结肾移植术后急性体液性排斥反应中针对HLA抗体的检测和处理经验.方法 肾移植受者15例,术前行HLA分型、交叉配型和群体反应性抗体(PRA)的检测,术后采用他克莫司(或环孢素A)、霉酚酸酯和糖皮质激素预防排斥反应.15例于肾移植后1～14 d发生抗体介导的急性排斥反应(AMR),采用抗胸腺细胞球蛋白(100 mg/d,使用5 d)治疗,或将环孢素A转换为他克莫司,当PRA明显升高,且血清中出现供者特异性HLA抗体时,即行血浆置换(PP),共行1～5次,每次PP后静脉输注免疫球蛋白(IVIG)100～150 mg/kg,最后1次PP后给予WIG 200～500mg/kg.结果 术后出现抗供者特异性HLA Ⅰ类抗体者9例,抗HLAⅡ类抗体者4例,同时出现抗Ⅰ、Ⅱ类抗体者2例.14例的AMR逆转,1例术后发生移植肾功能恢复延迟,彩色多普勒超声波显示移植肾血流灌注差,于术后第10天切除移植肾.并行二行肾移植.2例AMR后并发急性肾小管坏死,透析后移植肾功能恢复正常.抗排斥反应治疗期间患者均未发生严重感染.随访12～52个月,1例因慢性移植肾肾病恢复血液透析治疗,1例死于心血管疾病,其余患者移植肾功能稳定.结论 将ATG、PP和IVIG联合应用能有效逆转AMR.     

Hematuria and proteinuria in a mass school urine screening test

A total of 1,044 school children identified with hematuria and/or proteinuria during a mass school urine screening test were referred to pediatric nephrologists at 13 hospitals in Korea. These children had isolated hematuria (IH) (60.1%), isolated proteinuria (IP) (26.4%: transient, 19.6%; orthostatic, 4.9%; persistent, 1.9%) or combined hematuria and proteinuria (CHP) (13.5%). The patients history, physical examination, laboratory tests, kidney ultrasound and Doppler ultrasonography were obtained. Renal biopsies were performed on 113 children who showed severe proteinuria, hypertension, abnormal renal function, family history of chronic renal disease, systemic diseases or persistent hematuria and/or proteinuria for more than 12 months. IgA nephropathy (IgAN), thin basement membrane nephropathy (TBMN), membranoproliferative glomerulonephritis (MPGN), focal segmental glomerulosclerosis (FSGS), other GN, Alport syndrome and lupus nephritis were detected. IgAN and TBMN were the most common causes in the CHP group and IH group, respectively. Abnormal findings on the renal ultrasound with or without Doppler ultrasonography were noted in 147 cases (suspected nutcracker phenomenon, 65; increased parenchymal echogenicity, 40; hydronephrosis, 15). This study showed that the use of a mass school urine screening program can detect chronic renal disease in its early stage and recommends that more attention should be paid to identifying those children with CHP and massive proteinuria. A school urine screening program can detect chronic renal disease in its early stage. When mass screening is used, the initial aggressive diagnostic procedures such as renal biopsy are not needed. In addition, a regular follow-up for those children with IH and IP is certainly warranted.     

The Czech registry of renal biopsies. Occurrence of renal diseases in the years 1994-2000.

BACKGROUND: This report describes data collected by the Czech Registry of Renal Biopsies (CRRB). METHODS: Twenty-eight centres provided data on all biopsies of native kidneys performed in the Czech Republic (population 10.3 million) over the period 1994-2000. Data on serum creatinine concentration (sCr), 24 h proteinuria, haematuria, serum albumin level, arterial hypertension, diabetes mellitus, histological diagnosis and complications after renal biopsy were collected. RESULTS: Altogether 4004 biopsies in 3874 patients were performed (males 57.9%, children < or = 15 years 17.7%, elderly >60 years 14.3%). Microhaematuria was present in 65.9%, macrohaematuria in 9.2%, nephrotic proteinuria (> or = 3.5 g/24 h) in 39.3%, and low-grade proteinuria (<3.5 g/24 h) in 41.4%. Among adults, hypertension was present in 45.2%, mild renal insufficiency in 23% (sCr 111-200 micromol/l) and advanced renal insufficiency in 13.7% (sCr 201-400), while 11.5% of patients had sCr >400 micromol/l. The most frequent renal diseases were primary (59.8%) and secondary (25.4%) glomerulonephritis (GN). Tubulointerstitial nephritis (TIN) was observed in 4.4% and hypertensive nephroangiosclerosis in 3.4%. The samples were non-diagnostic in 4.6%. Among primary GNs, the most frequent diagnoses were: IgA nephropathy (IgAN) 34.5%, minimal change disease (MCD) 12.4%, non-IgA mesangioproliferative GN (MesGN) 11.3%, focal segmental glomerulosclerosis (FSGS) 10.8% and membranous GN (MGN) 9.3%. Among secondary GNs, systemic lupus erythematosus (SLE) represented 23.0%, necrotizing vasculitis (NV) 15.5%, Henoch-Schonlein purpura 5.7%, thin basement membrane glomerulopathy (TBN) 19.3%, Alport syndrome 6.9%, renal amyloidosis 9.9% and myeloma kidney 2.9%. Among children, the most common were IgAN (19.2%), MCD (17.6%) and TBM glomerulopathy (12.3%), while among the elderly the most common were MGN (11.0%), NV (10.7%) and amyloidosis (9.6%). The most common in patients with nephrotic proteinuria were MCD (50.5%) among children, but IgAN (24.6%) in adults aged 16-60 years and MGN (16.8%) among the elderly. IgAN (21.3%) and FSGS (8.3%) were the most common diagnoses among patients with mild renal insufficiency, but TIN (11.6%) and NV (11.3%) were the most common in more advanced renal insufficiency. Since 1999, diabetic patients represented 12.2% of adults, with mean proteinuria 8.9 g/24 h; diabetic glomerulosclerosis was found in 42.4% (with microhaematuria present in 66%) and non-diabetic renal diseases in 47.5% (IgAN in 17.5%, MGN and NAS in 11.1% and NV in 9.5%). The mean annual incidence (per million population) was: primary GN 32.4, secondary GN 13.8, IgAN 11.2, MCD 4.0, MesGN 3.7, FSGS 3.5, SLE 3.2, MGN 3.0, TBM 2.7, TIN 2.4 and NV 2.1. Ultrasound needle guidance was used in 56%, preferably in children (79%). The frequency of serious complications (gross haematuria, symptomatic haematoma, blood transfusion) remained at 3%. CONCLUSION: The CRRB provides important data on the epidemiology of GN based on a whole country population.