Hepatitis C and glomerulonephritis

Summary: Several systemic viral infections have been associated with the development of glomerular lesions. of the viruses that cause liver disease hepatitis B was the first to be recognized. the recent availability of serologic tests for the hepatitis C virus (HCV) has uncovered an association between HCV infection and renal disease. the principal glomerular lesion that develops is that of a membranoproliferative glomerulonephritis (MPGN), usually in association with antigenaemia and circulating immune complexes that have the characteristics of mixed cryoglobulinaemia represented by polyclonal IgG and monoclonal IgM with rheumatoid factor activity. the presence of a very high percentage of anti-HCV seropositivity in cryoglobulinaemic forms of MPGN suggests that the virus plays an important role in the pathogenesis of the associated immune complex glomerulonephritis. Precipitates containing HCV-RNA and circulating anti-HCV IgG and IgM have been found in the majority of such cases. the course of the renal disease that develops is progressive. Treatment with interferon alpha appears to attenuate the progression of the renal lesions, and the response to treatment appears to be closely related to the clearance of hepatitis C viraemia. Renal lesions also occur in the absence of clinical evidence of liver disease or mixed cryoglobulinaemia. In addition to MPGN, membranous glomerulonephropathy, IgA nephropathy and focal segmental glomerulosclerosis have been reported in these cases of HCV infection. the prevalence of glomerular lesions in patients with HCV infection remains to be determined. the available serologic tests for HCV are still in evolution. In the meantime, all patients presenting with glomerular disease should be screened for HCV.     

Minimal-change nephropathy and chronic hepatitis C infection: coincidental or associated?

Sir, Hepatitis C virus (HCV) infection is among the known main causesof glomerulonephritis. Membranoproliferative glomerulonephritisassociated with cryoglobulinaemia is the predominant form inHCV-infected patients. Less common glomerular diseases, i.e.membranoproliferative glomerulonephritis without cryoglobulinaemia,membranous glomerulonephritis, focal segmental glomerular sclerosis,proliferative glomerulonephritis, renal thrombotic microangiopathyassociated with anti-cardiolipin antibodies and fibrillary andimmunotacoid glomerulopathies, have also occurred in these patients.We encountered a patient with chronic     

Hepatitis C virus infection and renal disease after renal transplantation

Hepatitis C virus (HCV) infection is the main cause of chronic liver disease after renal transplantation (RT). It is considered in some series to be a risk factor for graft loss and patient death. Also, HCV has been implicated in the pathogenesis of glomerular diseases in native and transplanted kidneys. The presence of membranoproliferative (MP) or membranous (M) glomerulonephritis (GN) in HCV-positive patients has been well documented after RT, but there is no clear data concerning the real prevalence of HCV-induced glomerulonephritis. MPGN with or without cryoglobulinemia and MGN have been described in HCV RNA-positive patients in general without severe liver disease. Also, there is a possible association between HCV infection and acute/chronic transplant glomerulopathy. Renal thrombotic microangiopathy has been described in HCV-positive patients with positive anti-cardolipin antibodies. The pathogenesis of MPGN and MGN in HCV patients after RT seems to be similar to that which occurs in native kidneys: the deposition of immune complexes containing HCV proteins in the glomeruli. Renal biopsy, using light microscopy, immunofluorescence techniques, and electron microscopy, is useful to achieve a correct diagnosis. Unfortunately, interferon is not recommended due to the significant risk of rejection. The possibility of pegylated interferon needs to be tested. Ribavirin can improve proteinuria but HCV RNA remains positive. Finally, recent data suggest that the use of interferon in HCV patients on dialysis can negate HCV RNA and prevent associated glomerulonephritis after RT.     

Clinicopathologic features of glomerular lesions associated with hepatitis C virus infection in Japan

Background We determined the incidence of hepatitis C virus (HCV)-related glomerulonephritis in Japan and the glomerular localization of HCV-related antigens in this disorder. Methods We analyzed urinalysis findings in 100 consecutive Japanese patients with HCV chronic liver disease from 1993 to 1994. Immunohistochemical analysis using monoclonal or polyclonal antibodies to HCV-core antigen and polyclonal antibodies to HCV-envelope antigen was done on kidney specimens from 11 of 29 patients with antibody to HCV (anti-HCV-Ab). Results Eight of 100 patients had proteinuria, but only 2 cases (2%) were related to HCV nephropathy. Pathohistologic analysis showed 10 patients to have hepatic glomerulosclerosis, and 9 patients had mesangial proliferative glomerulonephritis involving primary immunoglobulin A nephropathy. Membranoproliferative glomerulonephritis was seen in 4 biopsy specimens that showed subendothelial electron-dense deposits and annular structures with characteristic cryogloblin. HCV core antigen was detected along the capillary walls with the same pattern as that of immunoglobulin G deposition and electron-dense deposits in 5 of 6 specimens from patients with both anti-HCV-Ab and HCV ribonucleic acid positive in the sera, but could not be detected in any of 3 specimens, from patients with anti-HCV-Ab but no HCV ribonucleic acid. Envelope antigen was not detected in the glomeruli of any specimens. Conclusions Glomerular lesions associated with HCV infection were characterized by deposition of immune complexes containing HCV core antigen and immunoglobulin G, and by the subendothelial deposition of cryoglobulin. These HCV-related glomerular diseases are rare in Japan (2% incidence), and these lesions should be distinguished from hepatic glomerulosclerosis related to advanced liver disease and other primary glomerular diseases.     

Hepatitis C virus-related kidney disease: an overview

Hepatitis C virus (HCV)-infection leads to chronic liver disease, but also to extra-hepatic manifestations, including kidney disease. We provide an overview of HCV-related kidney diseases in non-transplanted and in kidney transplant patients, and their therapies. Membranoproliferative glomerulonephritis, associated with Type 2 cryoglobulinemia, is the predominant Type of HCV-related glomerulonephritis. Membranous glomerulonephritis and focal segmental glomerular sclerosis are less commonly described. HCV infection seems to be linked to Type 2 diabetes mellitus, and might alter the progression of diabetic-related nephropathy. Patients infected by HCV should be annually screened for markers of kidney disease and, similarly, patients with membranoproliferative or membranous glomerulonephritis should be screened for HCV infection. After transplantation, cryoglobulinemia is frequent and is associated with HCV markers. HCV-related kidney disease requires specific treatment. In non-kidney-transplant patients, treatment relies on either only anti-HCV therapy in cases of moderate renal disease, or combined anti-viral and immunosuppressive therapies in cases of severe renal disease, i.e., nephrotic syndrome and/or progressive renal failure, and in diseases that are refractory to anti-HCV therapy. In kidney transplant patients, ribavirin monotherapy could be used cautiously, whereas rituximab might be a treatment of choice in the presence of cryoglobulinemia. In liver-transplant patients, in addition to anti-HCV therapy, rituximab might be also used.     

The association of hepatitis C infection with the onset of CKD and progression into ESRD

Hepatitis C virus (HCV) infection is not only an important cause of chronic liver disease, but extrahepatic manifestations are common and include chronic kidney disease (CKD). HCV is classically associated with cryoglobulinemic glomerulonephritis in the context of mixed cryoglobulinemia syndrome, but other glomerular diseases also occur and may be significantly under‐recognized. HCV may cause glomerular disease by immune complex deposition; however, other potential mechanisms by which HCV promotes CKD include a direct cytopathic effect of the virus on renal tissue, and by its association with accelerated atherosclerosis, insulin resistance, and chronic inflammation. Epidemiologic studies show HCV infection confers an increased risk of incident CKD and accelerates progression of CKD to end‐stage renal disease (ESRD) in the general population, as well as subpopulations including diabetic patients, those coinfected with human immunodeficiency virus (HIV), and kidney transplant recipients. Patients with CKD and HCV infection experience inferior clinical outcomes, including poorer quality of life and an increased risk of mortality. Treatment with interferon‐based regimens is associated with decreased risk of incident CKD and ESRD, though prior studies are limited by the small number of patients with HCV and CKD who underwent treatment. With the advent of new, well‐tolerated direct‐acting antiviral combinations that are not cleared by the kidneys, it is possible to treat all genotypes of HCV infection in patients with CKD and ESRD. More data on the effect of direct‐acting antivirals on CKD incidence and progression are necessary. However, there is every expectation that with improved access to HCV treatment, the burden of CKD in patients with HCV could significantly decline.     

Effect of combination therapy (ribavirin and interferon) in HCV-related glomerulopathy.

BACKGROUND: Hepatitis C virus (HCV) is a major cause of acute and chronic hepatitis throughout the world. Several extrahepatic manifestations, including glomerulonephritis, have been reported to be associated with this type of infection. Cryoglobulinaemic and non-cryoglobulinaemic membranoproliferative glomerulonephritis (MPGN) and membranous nephropathy (MN) are the commonest lesions associated with HCV. Results of treatment of these patients with interferon therapy have been disappointing, since relapse of the viraemia and subsequent relapse of the renal disease are major problems. Combination of interferon with ribavirin in patients with chronic liver disease has been shown to increase the rate of sustained response. METHODS: In this work, 20 patients with HCV-associated glomerulopathy were subjected to an in-depth evaluation of their kidney lesions and HCV involvement. Laboratory, histopathological, immunohistochemical, and electron-microscopy techniques were used. The patients received interferon therapy for 12 months; in interferon-resistant subjects, interferon was combined with ribavirin. RESULTS: MPGN was the commonest kidney lesion, being reported in 85% of these cases, followed by MN and mesangioproliferative glomerulonephritis (10 and 5% respectively). Mixed cryoglobulinaemia was encountered in 60% of the cases. Twelve months' anti-viral treatment resulted in aviraemia in 25% of cases, while liver enzymes were normalized in 75%, 24-h proteinuria significantly decreased (from median 4 g to 1.10 g, P=0.001), serum albumin increased (from median 2.50 to 3.55 g/dl, P=0.012), lower viral titres (from median 1.15 to 0.53 mega-Eq/ml, P=0.049), and C3 and C4 concentrations returned to normal. Basal serum creatinine and viral titres were important determinants of response to treatment. CONCLUSION: This study supports the relationship between HCV and glomerulonephritis, especially MPGN, and the use of a combination of interferon and ribavirin in the treatment of selected cases of HCV-related glomerulopathy.     

The pathogenesis of membranoproliferative glomerulonephritis in KwaZulu-Natal,South Africa is unrelated to hepatitis C virus infection

Idiopathic membranoproliferative glomerulonephritis (MPGN) is a well-defined clinicopathological entity with a poor prognosis, with 50% of patients progressing to end stage renal disease (ESRD) within 10 years. It was reported in about 36% of adult Black patients with nephrotic syndrome in our center previously [Seedat et al. 1988]. Hepatitis C virus (HCV) infection has been shown to be associated with cryoglobulinemic as well as non-cryoglobulinemic (or idiopathic glomerulonephritis). The aim of this study was to determine whether an association exists between HCV infection and idiopathic MPGN in a population with a relatively high prevalence of MPGN. We studied adult patients referred with glomerular disease over a two-year period, 104 patients had primary glomerulonephritis. All 23 (22%) patients with idiopathic MPGN were enrolled, as well as 32 age-matched patients presenting with other primary glomerular diseases. We examined serum from all 55 patients for evidence of HCV antibodies and HCV RNA. None of the 55 patients showed evidence of HCV infection. Chronic renal failure was present in 82.6% of the patients with idiopathic MPGN and it was advanced in 52,2%, who either were dialysis-requiring at presentation or progressed to ESRD soon thereafter; 30.4% had moderate chronic renal failure, while only 17.4% had normal renal function. HCV infection is not associated with idiopathic MPGN in our patients. Idiopathic MPGN remains an idiopathic disease, possibly with a poor prognosis in our population.     

Papillitis and vasculitis of the arteria spinalis anterior as complications of hepatitis C reinfection after liver transplantation

It is well known that hepatitis C virus (HCV)-related chronic liver disease may be associated with various immunological disorders including mixed cryoglobulinemia, which is accompanied by cutaneous vasculitis, arthralgias, membranoproliferative glomerulonephritis, and neuropathy in association with cryoprecipitable immune complexes in serum. We describe here the first case of central nervous system HCV infection with evidence of the virus in the cerebrospinal fluid in association with cryoglobulinemia in a patient who developed recurrent episodes of papillitis and vasculitis of the arteria spinalis anterior after liver transplantation. Received: 3 September 1996 Received after revision: 13 November 1996 Accepted: 6 December 1996     

Secondary IgA nephropathy

IgA nephropathy (IgAN) is the most common pattern of primary glomerulonephritis seen in the Western world. In the majority of cases the cause remains unknown. Cases of familial IgAN and secondary IgAN have been reported and these have provided insights into underlying genetic and environmental triggers for this common glomerular disease. Secondary IgAN is seen most commonly in patients with liver disease or mucosal inflammation, in particular affecting the gastrointestinal tract. A number of dietary and microbial antigens have been identified in circulating IgA immune complexes and mesangial IgA deposits, suggesting that environmental factors may play a role in the pathogenesis of IgAN. There is an increasing literature reporting associations between IgAN and other diseases. Whether these reports represent chance associations or genuine shared pathophysiology is discussed.     

A comprehensive study of the association between hepatitis C virus and glomerulopathy.

BACKGROUND: Hepatitis C virus (HCV)-related infection is commonly associated with a wide range of glomerulonephritides (GN) including membranoproliferative glomerulonephritis (MPGN). The causal link between HCV infection and renal disease has been postulated through the induction of cryoglobulinaemia and secondary GN. However, the detection of viral particles or genomes within the kidneys of HCV-infected patients has proved to be difficult. With that in mind, we have studied a population of Egyptian HCV-positive patients with associated GN in an attempt to detect viral particles, antigens or RNA within their kidneys. METHODS: Fifty patients were found to be HCV positive out of 303 who presented with a glomerulopathy between 1998 and 1999 at the Mansoura Urology and Nephrology Center, Egypt. Comprehensive investigations of these 50 patients were undertaken including an evaluation of their clinical, biochemical, histological, virological and immunological parameters. In addition, their kidney biopsy material was analysed by electron microscopy (EM) to detect viral particles, by immunohistochemistry to detect a viral core antigen and by RT-PCR to detect RNA. This was compared with 50 HCV-negative controls. RESULTS: Positivity for HCV antibodies was higher among patients with GN (38%) compared with healthy blood donors (16%). Genotype 4 was sequenced in 70% of the HCV-positive samples examined. MPGN was the most common type of GN accounting for 54% of patients. Extrarenal manifestations were absent in the majority (80%) of patients even though 54% had cryoglobulinaemia. EM revealed virus-like particles in 50% of biopsies. Immunohistochemistry failed to reveal HCV-related antigens in kidney sections. HCV RNA was detected in the cryoprecipitates in 66% of patients and 22% of frozen renal sections. Control sections were negative. CONCLUSION: Our findings suggest a causal link between HCV and GN based on the observation of virus-like particles as well as viral RNA within the kidney sections of patients with HCV-associated glomerulopathies.     

Long-term response to peginterferon in hepatitis C virus-associated nephrotic syndrome from focal segmental glomerulosclerosis

Abstract

Hepatitis C virus (HCV) infection is a global public health problem. Chronic HCV infection is an important cause of chronic liver disease. Since the first reported association between HCV and membranoproliferative glomerulonephritis (MPGN) in 1993, HCV has been described with other types of glomerular diseases, although less frequently. Focal segmental glomerulosclerosis (FSGS) is one such glomerular disease that has been rarely reported in association with HCV. Antiviral therapy with interferon and ribavirin has been shown to be beneficial in HCV-associated MPGN. The optimal therapy of HCV-associated FSGS is not currently known. To our knowledge, long-term response to pegylated interferon monotherapy in treatment of HCV-associated FSGS has not been reported. We report an adult patient with HCV-associated FSGS who presented with nephrotic syndrome and renal failure. Treatment with pegylated interferon alfa-2a monotherapy resulted in sustained virological response with a clinical remission of nephrotic syndrome and stabilization of renal function. Patient continued to remain in clinical remission of nephrotic syndrome with stable renal function, 5 years after treatment. We also briefly review the literature on HCV-associated glomerular diseases, particularly HCV-associated FSGS.     

Acquired and genetic complement abnormalities play a critical role in dense deposit disease and other C3 glomerulopathies

Dense deposit disease and glomerulonephritis with isolated C3 deposits are glomerulopathies characterized by deposits of C3 within or along the glomerular basement membrane. Previous studies found a link between dysregulation of the complement alternative pathway and the pathogenesis of these diseases. We analyzed the role of acquired and genetic complement abnormalities in a cohort of 134 patients, of whom 29 have dense deposit disease, 56 have glomerulonephritis with isolated C3 deposits, and 49 have primary membranoproliferative glomerulonephritis type I, with adult and pediatric onset. A total of 53 patients presented with a low C3 level, and 65 were positive for C3 nephritic factor that was significantly more frequently detected in patients with dense deposit disease than in other histological types. Mutations in CFH and CFI genes were identified in 24 patients associated with a C3 nephritic factor in half the cases. We found evidence for complement alternative pathway dysregulation in 26 patients with membranoproliferative glomerulonephritis type I. The complement factor H Y402H variant was significantly increased in dense deposit disease. We identified one at-risk membrane cofactor protein (MCP) haplotype for glomerulonephritis with isolated C3 deposits and membranoproliferative glomerulonephritis type I. Thus, our results suggest a critical role of fluid-phase alternative pathway dysregulation in the pathogenesis of C3 glomerulopathies as well as in immune complex-mediated glomerular diseases. The localization of the C3 deposits may be under the influence of MCP expression.     

Interferon and ribavirin treatment in patients with hepatitis C-associated renal disease and renal insufficiency.

BACKGROUND: Hepatitis C virus (HCV) infection is associated with renal manifestations, such as membranoproliferative glomerulonephritis (MPGN) with or without cryoglobulinaemia, membranous glomerulonephritis (MGN) and focal segmental glomerulosclerosis (FSGS). Standard treatment for HCV is interferon and ribavirin, but in renal insufficiency ribavirin has been contraindicated due to fear of side effects. METHODS: Seven patients, two with cryoglobulinaemia, vasculitic manifestations and glomerulonephritis (GN), four with MPGN and one with FSGS were treated with a combination of interferon and ribavirin. Two patients were given pegylated interferon and ribavirin. All patients had at presentation renal insufficiency, with a glomerular filtration rate (GFR) between 10 and 65 ml/min. One patient had HCV genotype 1, the remainder 2 and 3. Duration of therapy was according to genotype (6-12 months). Ribavirin in plasma was monitored by high-performance liquid chromatography (HPLC) to avoid over-dosing, aiming at a target concentration of 10-15 micromol/l. The main side effect of ribavirin, haemolytic anaemia, was monitored closely with haemoglobin controls. RESULTS: Six of seven patients became HCV-RNA-PCR negative and four of seven have maintained both virological and renal remission. One of seven has maintained virological and partial renal remission. One patient did not tolerate interferon, but is in renal remission with low-dose ribavirin. One vasculitis patient responded with complete remission, but relapsed virologically and had a minor vasculitic flare after 9 months. Only one patient with vasculitis had low-dose immunosuppression in addition to anti-viral therapy. Average daily ribavirin dose was 200-800 mg. Ribavirin-induced anaemia was managed in five of seven patients with low-dose iron and erythropoietin between 4000 and 20 000 IU/week. CONCLUSIONS: Interferon and ribavirin can with reasonable safety be used in HCV-related vasculitis and GN irrespective of renal function.     

The pathobiology of chronic allograft nephropathy: immune-mediated damage and accelerated aging

Chronic allograft nephropathy includes chronic calcineurin nephrotoxicity, recurrent and de novo glomerulonephritis and a group of disorders with graft dysfunction of unknown etiology designated chronic rejection. Review of risk factors of the latter category show that the chronic rejection lesions emerge in organs that have undergone injury. Despite the relevance of nonalloantigen-dependent progression factors in the tissue injury, alloantigen-dependent factors predominate in the pathogenesis. Lately, B cell responses have received increasing interest in transplant rejection and include responses against both major histocompatibility complex (MHC) and tissue-specific antigens, mainly on the endothelium and in the glomeruli. These humoral responses are thought to be involved in the development of vascular and glomerular lesions. Furthermore, at the tissue level, markers of senescence are found in the tubular epithelium contributing to the lesions of tubular atrophy and interstitial fibrosis.     

Beyond hepatorenal syndrome: glomerulonephritis in patients with liver disease

Liver disease is frequently associated with renal abnormalities. In liver cirrhosis, impaired hepatic clearance of immune complexes leads to their trapping in the kidney, causing the lesions of hepatic immunoglobulin A (IgA) nephropathy and hepatic glomerulosclerosis. Chronic hepatitis C virus (HCV) infection can induce cryoglobulinemia type II with membranoproliferative glomerulonephritis, whereas chronic hepatitis B virus (HBV) infection may cause membranous nephropathy, or, more rarely, polyarteritis nodosa. Treatment aims at eliminating the viral infection, in HCV infection with interferon alfa and ribavirin and in HBV infection with interferon alfa or lamivudine. Short-term immunosuppressive treatment may be indicated in patients with severe inflammation. In alpha1-antitrypsin deficiency with liver disease a membranoproliferative type of glomerulonephritis can occur. In addition, partial or complete deficiency is frequently observed in patients with c-ANCA-positive systemic vasculitis.     

A primer on recurrent and de novo glomerulonephritis in renal allografts

Accumulating evidence indicates that recurrent glomerulonephritis is the third most important cause of renal allograft loss at 10 years after transplantation. The proteinuria and elevated serum creatinine levels that result from recurrent glomerulonephritis are associated with cardiovascular morbidity and mortality. The exact prevalence of either recurrent or de novo post-transplantation glomerulonephritis is unknown because a considerable number of patients never undergo allograft biopsy, meaning that glomerulonephritis remains undiagnosed and a diagnosis of 'chronic rejection/chronic allograft nephropathy' is sometimes presumed. The lack of consensus regarding evaluation of kidney transplant recipients who exhibit slow deterioration of graft function is a major reason for underdiagnosis. All forms of glomerular disease can recur after transplantation, but the likelihood of recurrence differs according to type. Focal segmental glomerulosclerosis, membranoproliferative glomerulonephritis, IgA nephropathy and idiopathic diarrhea-negative hemolytic uremic syndrome often recur. Membranous nephropathy, focal segmental glomerulosclerosis, anti-glomerular basement membrane nephritis associated with Alport syndrome, and drug-induced thrombotic microangiopathy are the most common forms of de novo glomerulonephritis. This Review discusses the prevalence, risk factors, pathogenesis, clinicopathological features, and effects on graft outcome of recurrent and de novo glomerulonephritis in renal allografts. Treatment options are briefly outlined.     

Treatment of hepatitis C-associated glomerular disease

Hepatitis C virus (HCV) infection can lead to chronic active hepatitis, cirrhosis, and liver failure; however it is also associated with a wide range of extrahepatic features. Renal manifestations include cryoglobulinemic membranoproliferative glomerulonephritis and membranous nephropathy. Treatment of HCV with alpha-interferon is only moderately effective and suffers from a high relapse rate. More recently, combination therapy with ribavirin has led to improved suppression of HCV RNA levels. In this review we briefly describe the features of renal disease associated with HCV infection and discuss the therapeutic options.     

Immune complex glomerulonephritis associated with Klebsiella pneumoniae infection.

The kidneys of three patients who died of pneumonia due to Klebsiella pneumoniae were studied at autopsy by light and immunofluoerescent microscopy. One had no clinical evidence of renal disease; two had only microscopic hematuria and mild proteinuria. Light microscopy revealed focal proliferative glomerulonephritis in all three cases. Also in all three, immunofluorescent microscopy revealed a granular deposition of capsular polysaccharide antigens of Klebsiella pneumoniae in association with immunoglobulins and complement components in the mesangium and along the glomerular basement membrane. Furthermore, the glomerular bound immunoglobulins were eluted and demonstrated to contain antibodies specific to a capsular polysaccharide antigen of Klebsiella pneumoniae isolated from each patient. These findings may illustrate that the capsular polysaccharides of Klebsiella pneumoniae are antigenic, and that the immune complex deposition in the kidney during infection with this agent can be associated with renal morphological changes. Whether or not clinical evidence of nephritis occurs may depend on the characteristics of the infection and the host factors.     

Oxidants and iron in progressive kidney disease.

Oxidants derived either from leukocytes in proliferative glomerulonephritis or from resident glomerular cells in nonproliferative glomerulonephritis have been shown to have several biological effects relevant to chronic kidney disease. These include the ability of oxidants to damage the glomerular basement membrane and directly induce proteinuria, effects that would lead to a fall in the glomerular filtration rate and account for the morphologic changes observed in chronic kidney disease. In experimental models, the role of oxidants has been shown in both proliferative glomerulonephritis (eg, antiglomerular basement membrane antibody disease) as well as experimental models of minimal change disease and membranous nephropathy. Oxidants have also been shown to be an important mediator of the various pathways that have been implicated in diabetic nephropathy. Antioxidants and iron chelators have also been shown to retard functional and morphologic changes observed in progressive kidney disease. Taken together, these experimental studies suggest an important role of oxidants in chronic kidney disease.