Recurrent membranoproliferative glomerulonephritis after kidney transplantation. Kidney Int. 2010;77:721-728. [PMID: 20130531 DOI: 10.1038/ki.2010.1]

A Patient with Abnormal Kidney Function and a Monoclonal Light Chain in the Urine

Monoclonal gammopathy is increasingly recognized as a cause of kidney injury. These renal conditions behave differently than ones without monoclonal gammopathy and require specific treatment. To avoid misdiagnosis, testing for paraprotein should be performed in addition to vasculitis and autoimmune diseases serologies in adults with unexplained AKI or proteinuria. Because the prevalence of monoclonal gammopathy is much more common than glomerular diseases, the nephrotoxicity of the monoclonal protein must be confirmed before cytotoxic therapy is initiated. This can only be done by a kidney biopsy. After a monoclonal gammopathy of renal significant is verified, the evaluation should then focus on the identification of the pathologic clone, because therapy is clone specific. We present this patient to illustrate the clinical presentation of a patient with renal dysfunction and a monoclonal gammopathy. This patient is also used to discuss the diagnostic process in detail when monoclonal gammopathy-associated renal disease is suspected.

[Clinical approach to primary membranoproliferative glomerulonephritis]

Membranoproliferative glomerulonephritis represent a heterogeneous group of nephropathies. During the last five years, our understanding of membranoproliferative glomerulonephritis has greatly improved. Animal models and the study of complement genetics led to the dissection of the physiopathology of membranoproliferative glomerulonephritis, to the individualization of a new entity, C3 glomerulopathy, and to a new classification of these nephropathies. The study of large cohorts has also changed the clinical picture of membranoproliferative glomerulonephritis that has been long dominated by the severity of a single type of dense deposits disease. Finally, the rediscovery of complement through the study of the atypical haemolytic uremic syndrome and the availability in clinical practice of complement inhibitors have paved the way for new therapeutic approaches of membranoproliferative glomerulonephritis.

Treatment-resistant recurrent membranoproliferative glomerulonephritis in renal allograft responding to rituximab: case report

We report a case of idiopathic membranoproliferative glomerulonephritis (MPGN) recurring 2 years after a living-unrelated kidney transplantation. The disease was refractory to intravenous immunoglobulin and plasmapheresis. Treatment with 2 doses of rituximab resulted in remission of the disease. The disease relapsed 18 months later after an episode of cytomegalovirus pneumonitis. After treatment of the pneumonitis, a lung biopsy was performed owing to persistent chest symptoms, which revealed bronchiolitis obliterans with organizing pneumonia. Bone marrow examination and culture revealed presence of acid-fast bacilli, and culture grew Mycobacterium tuberculosis. A repeated course of rituximab was withheld because of infection with tuberculosis, the patient's chest symptoms, and rare reports of noninfectious lung disease after the use of rituximab. The patient continues to have proteinuria with impaired kidney function.

Frequency of the Original Kidney Disease and Its Effect on the Outcome of Kidney Transplant in the Urology-Nephrology Center Mansoura University

OBJECTIVES

Renal allograft function and graft survival depends on many factors, including the source of the graft, immunologic matching between donor and recipient, incidence of acute rejection, and recurrence of the original kidney disease. This work aimed to evaluate the effects of the original kidney disease on patient and graft survival.

MATERIALS AND METHODS

This was a retrospective, single-center study that included 2189 kidney transplant recipients who were transplanted at The Urology and Nephrology Centre, Mansoura University, between 1976 and 2010. Of 2189 recipients, 1350 patients with unknown original kidney disease were excluded, with the remaining 839 patients divided into 4 groups according to their original kidney disease.

RESULTS

We found pretransplant dialysis and blood transfusion to be statistically significant among the 4 groups. Regarding induction immunosuppressive therapy, a statistical significance was found between the 4 groups regarding the presence and type of induction therapy, with no statistical significance regarding the type of maintenance immunosuppression. There was no statistical significance between the 4 groups regarding the incidence of acute and chronic rejection. We also found recurrence of original kidney disease to be statistically significant in the 4 groups, particularly in the group that included patients with glomerular disease, where the highest rate of recurrence was reported in patients with focal segmental glomerulosclerosis and membranoproliferative glomerulonephritis, and patient and graft survival was also statistically significant.

CONCLUSIONS

The original kidney disease has an effect on renal allograft function and graft and patient survival.

Membranoproliferative glomerulonephritis recurrence after kidney transplantation: using the new classification

Background

Membranoproliferative glomerulonephritis (MPGN) is an uncommon glomerular disorder that may lead to end stage renal disease (ESRD). With new understanding of the disease pathogenesis, the classical classification as MPGN types I, II, III has changed. Data on post-transplant MPGN, in particular with the newly refined classification, is limited. We present our center’s experience of MPGN after kidney transplantation using the new classification.

Methods

This is a retrospective study of 34 patients with ESRD due to MPGN who received 40 kidney transplants between 1994 and 2014. We reviewed the available biopsies’ data using the new classification. We assessed post transplantation recurrence rate, risk factors of recurrence, the response to therapy and allografts’ survival.

Results

Median time of follow up was 5.3 years (range 0.5–14 years). Using the new classification, we found that pre-transplant MPGN disease was due to immune complex-mediated glomerulonephritis (ICGN) in 89 % of cases and complement-mediated glomerulonephritis (CGN) in 11 %. Recurrence was detected in 18 transplants (45 %). Living related allografts (P = 0.045), preemptive transplantations (P = 0.018), low complement level (P = 0.006), and the presence of monoclonal gammopathy (P = 0.010) were associated with higher recurrence rate in ICGN cases. Half of the patients with recurrence lost their allografts. The use of ACEi/ARB was associated with a trend toward less allograft loss.

Conclusions

MPGN recurs at a high rate after kidney transplantation. The risk of MPGN recurrence increases with preemptive transplantation, living related donation, low complement level, and the presence of monoclonal gammopathy. Recurrence of MPGN leads to allograft failure in half of the cases.

Changing Kidney Allograft Histology Early Posttransplant: Prognostic Implications of 1-Year Protocol Biopsies

Allograft histology 1 year posttransplant is an independent correlate to long-term death-censored graft survival. We assessed prognostic implications of changes in histology first 2 years posttransplant in 938 first kidney recipients, transplanted 1999-2010, followed for 93.4 ± 37.7 months. Compared to implantation biopsies, histology changed posttransplant showing at 1 year that 72.6% of grafts had minor abnormalities (favorable histology), 20.2% unfavorable histology, and 7.2% glomerulonephritis. Compared to favorable, graft survival was reduced in recipients with unfavorable histology (hazards ratio [HR] = 4.79 [3.27-7.00], p < 0.0001) or glomerulonephritis (HR = 5.91 [3.17-11.0], p < 0.0001). Compared to unfavorable, in grafts with favorable histology, failure was most commonly due to death (42% vs. 70%, p < 0.0001) and less commonly due to alloimmune causes (27% vs. 10%, p < 0.0001). In 80% of cases, favorable histology persisted at 2 years. However, de novo 2-year unfavorable histology (15.3%) or glomerulonephritis (4.7%) related to reduced survival. The proportion of favorable grafts increased during this period (odds ratio = 0.920 [0.871-0.972], p = 0.003, per year) related to fewer DGF, rejections, polyoma-associated nephropathy (PVAN), and better function. Graft survival also improved (HR = 0.718 [0.550-0.937], p = 0.015) related to better histology and function. Evolution of graft histologic early posttransplant relate to long-term survival. Avoiding risk factors associated with unfavorable histology relates to improved histology and graft survival.

Monoclonal gammopathy: The good, the bad and the ugly

Monoclonal gammopathy of undetermined significance (MGUS) is a condition characterized by the presence of a monoclonal gammopathy (MG) in which the clonal mass has not reached a predefined state in which the condition is considered malignant. It is a precursor to conditions such as multiple myeloma or lymphoma at a rate of ~1%/year. Thus, from a hematologic standpoint, MGUS is a fairly benign condition. However, it is now recognized that organ damage resulting from just the MG without the need MM or lymphoma can occur. One of the most recognized is nephropathy secondary to monoclonal gammopathy of renal significance (MGRS). Other well-recognized conditions include neuropathies, oculopathies and dermopathies. Some conditions such as autoimmune diseases and coagulopathies are less common and recognized. Finally, systemic involvement of multiple organs is well described in several entities. In all of these conditions, the role of the MG is no longer insignificant. Thus, the term MGUS should be avoided when describing these entities.

Hematologic characteristics of proliferative glomerulonephritides with nonorganized monoclonal immunoglobulin deposits

OBJECTIVE

To study the hematologic characteristics of proliferative glomerulonephritides (GNs) from nonorganized glomerular monoclonal immunoglobulin (MIg) deposition (MIPG).

PATIENTS AND METHODS

The pathology database at Mayo Clinic (Rochester, Minnesota) was used to find patients with MIPG who underwent a kidney biopsy between January 1, 2008, and December 31, 2013. Retrospective medical record review was conducted in the identified cohort (N=60).

RESULTS

The median patient age was 56 years (interquartile range, 47-62 years) and the estimated glomerular filtration rate was 36 mL/min/1.73 m(2) (interquartile range, 22-52 mL/min/1.73 m(2)). Most patients had IgG MIg deposits (90%; 54 of 60) and a membranoproliferative pattern (48%; 29 of 60). A circulating nephropathic MIg was detected by serum immunofixation (SIFE(+)) in 20% (12 of 59) and by abnormal serum free light chain ratio (sFLCR(+)) in 21% (12 of 56). The subsets of SIFE(+) and sFLCR(+) incompletely overlapped. The nephropathic clone was found by bone marrow testing (BM(+)) in 25% (10 of 40; 6 plasma cell clones [5 IgG; 1 IgA], 3 chronic lymphocytic leukemia [all IgG], and 1 lymphoplasmacytic clone [IgM]). The clone detection rate was significantly higher in patients with SIFE(+) (P<.001) and in those with SIFE(+) and/or sFLCR(+) (P<.001). Patients with SIFE(+) and BM(+) frequently had IgG1-restricted MIg deposits on renal biopsy immunofluorescence (P=.005). Most BM(+) patients required flow cytometry and immunohistochemical analysis of the marrow specimen for accurate diagnosis.

CONCLUSION

Undetectable circulating nephropathic MIg and pathologic clones characterize most MIPG. Immunoglobulin isotype may predict detectability of MIg and clone by currently available technology. Bone marrow evaluation, including flow cytometry and immunohistochemical analysis, should be performed for SIFE(+) and/or sFLCR(+). More sensitive clone-identifying techniques in the marrow and extramedullary tissue are needed when SIFE and sFLCR test negative.

Primary disease recurrence—effects on paediatric renal transplantation outcomes

Primary disease recurrence after renal transplantation is mainly diagnosed by examination of biopsy samples, but can also be associated with clinical symptoms. In some patients, recurrence can lead to graft loss (7-8% of all graft losses). Primary disease recurrence is generally associated with a high risk of graft loss in patients with focal segmental glomerulosclerosis, membranous proliferative glomerulonephritis, primary hyperoxaluria or atypical haemolytic uraemic syndrome. By contrast, disease recurrence is associated with a limited risk of graft loss in patients with IgA nephropathy, renal involvement associated with Henoch-Schönlein purpura, antineutrophil cytoplasmic antibody-associated glomerulonephritis or lupus nephritis. The presence of systemic diseases that affect the kidneys, such as sickle cell anaemia and diabetes mellitus, also increases the risk of delayed graft loss. This Review provides an overview of the epidemiology, pathophysiology and management of primary disease recurrence in paediatric renal graft recipients, and describes the overall effect on graft survival of each of the primary diseases listed above. With appropriate management, few paediatric patients should be excluded from renal transplantation programmes because of an increased risk of recurrence.

New aspects on the pathogenesis of renal disorders related to monoclonal gammopathies

BACKGROUND

Multiple myeloma and other related monoclonal gammopathies are frequently encountered conditions associated with renal damage, especially in elderly population. They are arising from clonal proliferation of plasma cells in bone marrow producing various quantities of abnormal monoclonal immunoglobulins, or their components/fragments.

SUMMARY

These abnormal proteins differ from normal immunoglobulins in the amino acid sequence and in the three-dimensional structure of the molecule, which may determine their toxicity. Kidney seems to be a target organ as a major catabolic site. The pathology of renal disease is highly heterogeneous involving a variety of different mechanisms, which are divided into immunoglobulin dependent and immunoglobulin independent mechanisms. The Ig-dependent mechanisms may involve the four components of the kidney parenchyma, and the primary structure of these proteins determine the pattern of renal disease.

KEY MESSAGE

This review summarizes the existing literature in the pathobiology of multiple myeloma, and the pathological properties of the M-proteins, focusing on the mechanisms of the renal manifestations related to these abnormal proteins, especially glomerular injury. Also it supports the opinion that monoclonal gammopathy of undetermined significance (MGUS) should not be used in cases where there is proven renal impairment due to these proteins, even if it is mild and does not meet the current criteria.

Advances in the understanding of complement mediated glomerular disease: implications for recurrence in the transplant setting

Recent advances in the understanding of the role of complement in glomerular disease allow for more accurate assessment of the risk of disease recurrence after transplantation, and inform the development of targeted treatment strategies to overcome specific defects in the alternate pathway of the complement system. These advances along with remaining knowledge deficits are reviewed with specific relevance to membranoproliferative glomerulonephritis (MPGN) and C3 glomerulopathy, a heterogenous group of diseases with a high rate of recurrence leading to allograft failure. Recommendations to establish an accurate diagnosis and inform therapeutic decision making in transplant candidates with a histologic diagnosis of MPGN are provided.

Current concepts in C3 glomerulopathy

Complement component 3 glomerulopathy (C3G) is a recently defined entity comprising of dense deposit disease and C3 glomerulonephritis. The key histological feature is the presence of isolated C3 deposits without immunoglobulins. Often masqueradng as some of the common glomerulonephritides this is a prototype disorder occurring from dysregulated alternate complement pathway with recently identified genetic defects and autoantibodies. We review the pathophysiology, clinical features, and diagnostic and treatment strategies.

In search of an effective treatment for recurrent mesangiocapillary glomerulonephritis in the renal allograft

In patients with end-stage kidney disease (ESKD) secondary to mesangiocapillary glomerulonephritis (MCGN), recurrent disease post transplantation is a common cause of graft loss. We report a case of a 33-year-old female with ESKD due to idiopathic MCGN who developed recurrent disease in two consecutive renal allografts. Recurrent disease was diagnosed two months after receiving her primary transplant from a live related donor. Oral cyclophosphamide was initiated but discontinued after 10 months due to cystitis. This was followed by rapid deterioration in her renal function. Despite salvage therapy with rituximab, the graft was lost 2 years post transplantation. After 7 years on haemodialysis, the patient received a second graft from a deceased donor. Recurrent MCGN was once again diagnosed one year post transplantation. She was treated with plasma exchange and rituximab. Despite ongoing nephrotic range proteinuria, her graft function remained stable 2 years post transplantation. The optimal therapy for recurrent MCGN is unknown at this stage. It is hoped that a better understanding of its pathogenesis will enable the development of more effective and targeted therapies.

Recurrent proliferative glomerulonephritis with monoclonal immunoglobulin G deposits leads to rapid graft loss after kidney transplantation: a case report

We present a case of recurrent proliferative glomerulonephritis with monoclonal immunoglobulin G (IgG) deposits (PGNMID) that progressed rapidly to allograft failure. A 56-year-old man had progressed to end-stage renal failure within 1 year after the diagnosis of membranoproliferative glomerulonephritis (MPGN) by kidney biopsy. He underwent living donor kidney transplantation from his brother 6 months later. Serial allograft biopsies revealed early glomerular deposition of IgG, C1q, and C3 at post-operative day 26, and gradual progression of the glomerular deposition and histology of glomerulonephritis. Several immunosuppressive therapies did not prevent proteinuria, microhematuria, and graft dysfunction, and the patient returned to hemodialysis at 7 months after transplantation. Retrospectively, we demonstrated monoclonal IgG3κ deposition in the native and allograft kidney, and the patient was diagnosed with recurrent PGNMID. The serial graft biopsies revealed the pathological details of the progression of PGNMID. This is a rare case of PGNMID that recurred and progressed rapidly to graft failure after kidney transplantation.

Update on membranoproliferative GN

Membranoproliferative GN represents a pattern of injury seen on light microscopy. Historically, findings on electron microscopy have been used to further subclassify this pathologic entity. Recent advances in understanding of the underlying pathobiology have led to a proposed classification scheme based on immunofluorescence findings. Dysregulation of the complement system has been shown to be a major risk factor for the development of a membranoproliferative GN pattern of injury on kidney biopsy. Evaluation and treatment of this complex disorder rest on defining the underlying mechanisms.

Myeloma-related kidney disease

Multiple myeloma is a malignant plasma cell disorder characterized by the overproduction of monoclonal proteins. The kidney is 1 of the major target organs of multiple myeloma. Most often, this is the result of the monoclonal proteins, which can injure the kidney via several mechanisms. In some cases, direct invasion by myeloma cells and/or bone marrow cells can also result in kidney injury. A kidney biopsy can help distinguish the various myeloma-related kidney diseases and aid in the treatment plan.

Clinical findings, pathology, and outcomes of C3GN after kidney transplantation

C3 glomerulonephritis (C3GN) results from abnormalities in the alternative pathway of complement, and it is characterized by deposition of C3 with absent or scant Ig deposition. In many patients, C3GN progresses to ESRD. The clinical features, pathology, and outcomes of patients with C3GN receiving kidney transplantation are unknown. Between 1996 and 2010, we identified 21 patients at our institution who received a kidney transplant because of ESRD from C3GN. The median age at the time of initial diagnosis of C3GN at kidney biopsy was 20.8 years. The median time from native kidney biopsy to dialysis or transplantation was 42.3 months. Of 21 patients, 14 (66.7%) patients developed recurrent C3GN in the allograft. The median time to recurrence of disease was 28 months. Graft failure occurred in 50% of patients with recurrent C3GN, with a median time of 77 months to graft failure post-transplantation. The remaining 50% of patients had functioning grafts, with a median follow-up of 73.9 months. The majority of patients had hematuria and proteinuria at time of recurrence. Three (21%) patients were positive for monoclonal gammopathy and had a faster rate of recurrence and graft loss. Kidney biopsy at the time of recurrence showed mesangial proliferative GN in eight patients and membranoproliferative GN in six patients. All allograft kidney biopsies showed bright C3 staining (2-3+), with six biopsies also showing trace/1+ staining for IgM and/or IgG. To summarize, C3GN recurs in 66.7% of patients, and one half of the patients experience graft failure caused by recurrence.

Monoclonal gammopathy-associated proliferative glomerulonephritis

Monoclonal gammopathy is characterized by circulating monoclonal immunoglobulin owing to clonal proliferation of immunoglobulin-producing B lymphocytes or plasma cells. Clonal proliferation of B lymphocytes is seen in B-cell lymphoma/leukemia, and clonal plasma cell proliferation is seen in multiple myeloma and monoclonal gammopathy of undetermined significance. The monoclonal immunoglobulin in the setting of a B-cell or plasma cell disorder can cause a proliferative glomerulonephritis via 2 mechanisms: (1) glomerular deposition of the monoclonal immunoglobulin with activation of the classical pathway of complement (direct mechanism), resulting in an immunoglobulin-positive C3-positive glomerulonephritis, and (2) glomerular deposition of complement factors of the alternative and terminal pathway via inhibition of alternative pathway-regulating proteins by the monoclonal immunoglobulin (indirect mechanism), resulting in immunoglobulin-negative C3-positive glomerulonephritis (C3 glomerulopathy). Evaluation should include serum and urine electrophoresis and immunofixation as well as serum-free light-chain assay. If a monoclonal immunoglobulin is detected on these tests, bone marrow biopsy or imaging is needed to exclude more advanced plasma cell dyscrasia. Evaluation of alternative pathway of complement should be done in patients with Ig-negative C3-positive glomerulonephritis. If monoclonal gammopathy is due to an underlying malignant disease such as myeloma, lymphoma, or chronic lymphocytic leukemia, then specific treatment should be aimed at treating the malignant disease, with the goal of eradicating the clonal cells producing the immunoglobulin. In contrast, if monoclonal gammopathy is due to a monoclonal gammopathy of undetermined significance, treatment options include bortezomib, cyclophosphamide, and dexamethasone for a non-IgM monoclonal immunoglobulin and rituximab alone or in combination with cyclophosphamide and dexamethasone for an IgM monoclonal immunoglobulin.

C3 glomerulonephritis: clinicopathological findings, complement abnormalities, glomerular proteomic profile, treatment, and follow-up

C3 Glomerulonephritis (C3GN) is a recently described disorder that typically results from abnormalities in the alternative pathway of complement. Here, we describe the clinical features, kidney biopsy findings, alternative pathway abnormalities, glomerular proteomic profile, and follow-up in 12 cases of C3GN. This disorder equally affected all ages, both genders, and typically presented with hematuria and proteinuria. In both the short and long term, renal function remained stable in the majority of patients with native kidney disease. In two patients, C3GN recurred within one year of transplantation and resulted in a decline in allograft function. Kidney biopsy mainly showed a membranoproliferative pattern; although both mesangial proliferative and diffuse endocapillary proliferative glomerulonephritis were noted. Alternative pathway abnormalities were heterogeneous; both acquired and genetic. The most common acquired abnormality was the presence of C3 nephritic factors, while the most common genetic finding was the presence of H402 and V62 alleles of Factor H. In addition to these risk factors, other abnormalities included Factor H auto-antibodies and mutations in CFH, CFI and CFHR genes. Laser dissection and mass spectrometry of glomeruli from patients with C3GN showed accumulation of alternative pathway and terminal complement complex proteins. Thus, C3GN results from diverse abnormalities of the alternative complement pathway leading to subsequent glomerular injury.

How I treat monoclonal gammopathy of renal significance (MGRS)

Recently, the term monoclonal gammopathy of renal significance (MGRS) was introduced to distinguish monoclonal gammopathies that result in the development of kidney disease from those that are benign. By definition, patients with MGRS have B-cell clones that do not meet the definition of multiple myeloma or lymphoma. Nevertheless, these clones produce monoclonal proteins that are capable of injuring the kidney resulting in permanent damage. Except for immunoglobulin light chain amyloidosis with heart involvement in which death can be rapid, treatment of MGRS is often indicated more to preserve kidney function and prevent recurrence after kidney transplantation rather than the prolongation of life. Clinical trials are rare for MGRS-related kidney diseases, except in immunoglobulin light chain amyloidosis. Treatment recommendations are therefore based on the clinical data obtained from treatment of the clonal disorder in its malignant state. The establishment of these treatment recommendations is important until data can be obtained by clinical trials of MGRS-related kidney diseases.

Recurrence of glomerulonephritis after renal transplantation

Recurrence of glomerulonephritis following renal transplantation is considered an important cause of allograft failure. The incidence of recurrence of glomerulonephritis varies widely depending on the definition of recurrence (pathologic recurrence or clinicopathologic recurrence) and the original glomerular disease. Moreover the impact of recurrence of glomerular disease on allograft outcome varies widely between different forms of glomerulonephritis. Whereas IgA nephritis recurs in up to one third of transplanted patients, this is not associated with adverse effects on graft survival. In contrast, recurrent focal segmental glomerulosclerosis and membranoproliferative glomerulopathy have an unfavorable prognosis. Overall, long-term graft survival in patients transplanted for glomerulonephritis is comparable to survival in patients with other causes of ESRD. In recent years, several mechanisms for recurrent disease after transplantation (e.g. PLA2R antibodies in membranous nephropathy and suPAR in FSGS) have been identified, and these findings have helped to elucidate the pathogenesis of glomerular diseases. Although renal transplantation is the treatment of choice for end-stage renal disease as a consequence of glomerulonephritis, further studies are required to develop optimal strategies to prevent, diagnose and treat recurrent glomerular diseases.

Impact of graft loss among kidney diseases with a high risk of post-transplant recurrence in the paediatric population

BACKGROUND

Some kidney diseases tend to recur in the renal allograft after transplantation. We studied the risk of graft loss among primary renal diseases known for their high risk of recurrence and compared it with that of patients with hypoplasia and/or dysplasia.

METHODS

Within the European Society of Paediatric Nephrology and European Renal Association and European Dialysis and Transplant Association (ESPN/ERA-EDTA) registry, we studied children from 33 countries who received a kidney transplant before the age of 20 between 1990 and 2009. Patients were censored after 5 years of follow-up and cumulative incidence competing risk analysis was used to calculate survival curves.

RESULTS

Patients with focal and segmental glomerulosclerosis (FSGS), haemolytic uraemic syndrome (HUS), membranoproliferative glomerulonephritis Type I or II (MPGN), IgA nephropathy or Henoch Schönlein Purpura (HSP/IgA) or systemic lupus erythomatosus (SLE) underwent pre-emptive transplantation significantly less often than patients with hypoplasia and/or dysplasia. The rate of living donation was lower among patients with FSGS and SLE than in patients with hypoplasia and/or dysplasia. In comparison with hypoplasia and/or dysplasia patients with a risk of 14.4%, the 5-year risk of graft loss was significantly increased in patients with FSGS (25.7%) and MPGN (32.4%) while it was not significantly increased in children with HUS (18.9%), HSP/IgA (16.3%) or SLE (20.3%). One-year graft survival strongly improved among HUS patients from 17.1% in 1995-1999 to 3.6% in 2005-2009 and was not accompanied by a decrease in the number of transplantations.

CONCLUSION

The risk of graft loss is increased among specific causes of renal failure with a high risk of post-transplant recurrence. It seems likely that, due to anticipation of such risk, physicians perform less pre-emptive transplantation and provide fewer grafts from living related donors in patients with these conditions. Improved risk stratification by physicians, resulting in the identification of patients with HUS at higher or lower risk of recurrence, might explain the much improved graft survival rates.

Monoclonal gammopathy of renal significance: when MGUS is no longer undetermined or insignificant

Multiple myeloma is the most frequent monoclonal gammopathy to involve the kidney; however, a growing number of kidney diseases associated with other monoclonal gammopathies are being recognized. Although many histopathologic patterns exist, they are all distinguished by the monoclonal immunoglobulin (or component) deposits. The hematologic disorder in these patients is more consistent with monoclonal gammopathy of undetermined significance (MGUS) than with multiple myeloma. Unfortunately, due to the limitations of the current diagnostic schema, they are frequently diagnosed as MGUS. Because treatment is not recommended for MGUS, appropriate therapy is commonly withheld. In addition to end-stage renal disease, the persistence of the monoclonal gammopathy is associated with high rates of recurrence after kidney transplantation. Preservation and restoration of kidney function are possible with successful treatment targeting the responsible clone. Achievement of hematologic complete response has been shown to prevent recurrence after kidney transplantation. There is a need for a term that properly conveys the pathologic nature of these diseases. We think the term monoclonal gammopathy of renal significance is most helpful to indicate a causal relationship between the monoclonal gammopathy and the renal damage and because the significance of the monoclonal gammopathy is no longer undetermined.

Pathogenesis of the C3 glomerulopathies and reclassification of MPGN

Until recently, membranoproliferative glomerulonephritis (MPGN) was clinically classified as either primary, idiopathic MPGN or as secondary MPGN when an underlying aetiology was identifiable. Primary MPGN was further classified into three types--type I, type II, and type III--based principally on the ultrastructural appearance and location of electron-dense deposits. Both the clinical and histopathologic schemes presented problems, however, as neither was based on disease pathogenesis. An improved understanding of the role of complement in the pathogenesis of MPGN has led to a proposed reclassification into immunoglobulin-mediated disease (driven by the classical complement pathway) and non-immunoglobulin-mediated disease (driven by the alternative complement pathway). This reclassification has led to improved diagnostic clinical algorithms and the emergence of a new grouping of diseases known as the C3 glomerulopathies, best represented by dense deposit disease and C3 glomerulonephritis. In this Review, we re-examine the previous and current classification schemes of MPGN, focusing on the role of complement. We survey current data about the pathogenesis of the C3 glomerulopathies, including familial studies and patient cohorts from the USA and Europe. In addition, we discuss the diagnosis, treatment, and prognosis of the C3 glomerulopathies.

Idiopathic membranoproliferative glomerulonephritis: does it exist?

When membranoproliferative glomerulonephritis (MPGN) was first delineated as a discrete clinico-pathological entity more than a half-century ago, most cases were regarded as idiopathic (or primary) in nature. Advances in analysis of pathogenetic mechanisms and etiologies underlying the lesion of MPGN have radically altered the prevalence of the truly idiopathic form of MPGN. In addition, MPGN as a category among renal biopsies showing glomerulonephritis has diminished over time. In the modern era, MPGN is mainly classified morphologically on the basis of immunoglobulin (Ig; monoclonal or polyclonal) and complement (C3 only or combined with Ig) deposition and secondarily on the basis of its appearance on ultra-structural examination. Idiopathic MPGN is a diagnosis of exclusion, at least in many adults and a portion of children, and a systematic approach to evaluation will often uncover a secondary cause, such as an infection, autoimmune disease, monoclonal gammopathy, neoplasia, complement dysregulation or a chronic thrombotic microangiopathy. Idiopathic MPGN remains an 'endangered species' after its separation from these known causes.

Recurrent membranoproliferative glomerulonephritis after second renal graft treated with plasmapheresis and rituximab

We present a case of a 45-year-old man who suffered from idiopatic membranoproliferative glomerulonephritis (MPGN) in the native kidney that relapsed after his first and second renal grafts. The patient was diagnosed in 1990 with lobular MPGN type I, receiving his first renal graft in 1996. In 2001, a biopsy showed recurrence of MPGN type I (rMPGN). He underwent a second renal graft in 2008. In January 2010, he experienced increased proteinuria and creatinine. Upon electron microscopy of a renal graft biopsy we diagnosed a new rMPGN. At the time of the biopsy, complement levels were normal, although C3 and C4 decreased further. We administered 12 plasmapheresis (PP) sessions and four doses of rituximab. Due to persistent renal impairment, we performed a new biopsy 3 months later, showing less severity of the acute lessions. He received a new cycle of treatment (PP+rituximab). One year later, his renal function was stable with a creatinine ranging between 2 and 2.5 mg/dL and a protein/creatinine ratio less than 1 mg/mg. We concluded that the treatment stopped the disease progression.

Impact of recurrent glomerulonephritis on renal graft survival

BACKGROUND

Glomerular disease causes graft loss in the intermediate and long term, especially recurrent primary renal disease, negatively impacting graft survival. Thus, it must be considered a differential diagnosis in the evaluation of chronic graft dysfunction.

METHODS

The objectives of our study were to compare the impacts of primary glomerular disease on graft survival and association with interstitial fibrosis/tubular atrophy (IFTA) or transplant glomerulopathy. We examined the influence of the relapse of glomerulonephritis (GN) on renal graft survival in a retrospective study of 1057 patients undergoing renal transplantations between March 1981 and October 2009. Among this group, 128 patients were diagnosed with pretransplant GN by renal biopsy. We examined graft survival on recurrence compared with IFTA and transplant glomerulopathy using Kaplan-Meier analysis.

RESULTS

We analyzed a cohort of 128 patients who were diagnosed with pretransplant GN by renal biopsy, including 28.9% (37) of whom were males. The mean age was 42.04 ± 13.82 years. The most frequent type was immunoglobulin A GN (IgAGN; 31.3%), followed by membranoproliferative GN (MPGN; 28.9%), rapidly progressive GN (RPGN; 16.4%), focal-segmental GN (FSGN; 13.3%), membranous GN (9.4%), and minimal change GN; (0.8%). Among the 16 cases (12.5%) of GN recurrence; MPGN was associated most frequently (n = 10, 28.9%), followed by FSGN (n = 4, 23.5%), RPGN (n = 1, 4.8%), and IgAGN (n = 1, 2.5%). We noted that 11.8% of subjects to be positive for hepatitis C virus; while 3.9% were hepatitis B virus(HBV)-positive. We observed no differences in hepatic serology between patients who experienced recurrence (HBV 6.3% vs hepatitis C virus [HCV] 18.8%) compared with IFTA (HBV 3.1% vs HCV 9.4%). Fifty-one patients (39.8%) were biopsied after transplantation due to impaired renal function: there were recurrences of GN in 12.5% (n = 16), IFTA in 25% (n = 32), and transplant glomerulopathy in 2.3% (n = 3) cases. The average graft survival in our cohort was 8.36 ± 0.59 years. The median patient survival among those who experienced a recurrence was 8.36 ± 1.79 years; 7.19 ± 1.01 years in IFTA patients; and 3.31 ± 0.91 years in patients with transplant glomerulopathy (log-rank P = .06). Upon multivariate analysis, recurrence of GN was not an independent predictor of renal loss.

CONCLUSIONS

MPGN was the type of GN that recurred most frequently followed by FSGN. No differences in graft survival were noted between long-term recurrence of GN and other causes of chronic graft dysfunction. The recurrence of primary disease did not worsen the renal graft prognosis versus other causes of chronic graft dysfunction.

Membranoproliferative glomerulonephritis: pathogenetic heterogeneity and proposal for a new classification

Membranoproliferative glomerulonephritis (MPGN) is a pattern of injury that results from subendothelial and mesangial deposition of Igs caused by persistent antigenemia and/or circulating immune complexes. The common causes of Ig-mediated MPGN include chronic infections, autoimmune diseases, and monoclonal gammopathy/dysproteinemias. On the other hand, MPGN also can result from subendothelial and mesangial deposition of complement owing to dysregulation of the alternative pathway (AP) of complement. Complement-mediated MPGN includes dense deposit disease and proliferative glomerulonephritis with C3 deposits. Dysregulation of the AP of complement can result from genetic mutations or development of autoantibodies to complement regulating proteins with ensuing dense deposit disease or glomerulonephritis with C3 deposits. We propose a new histologic classification of MPGN and classify MPGN into 2 major groups: Ig-mediated and complement-mediated. MPGN that is Ig-mediated should lead to work-up for infections, autoimmune diseases, and monoclonal gammopathy. On the other hand, complement-mediated MPGN should lead to work-up of the AP of complement. Initial AP screening tests should include serum membrane attack complex levels, an AP functional assay, and a hemolytic assay, followed by tests for mutations and autoantibodies to complement-regulating proteins.

Glomerulonephritis with isolated C3 deposits and monoclonal gammopathy: a fortuitous association?

BACKGROUND AND OBJECTIVES

Glomerular deposition of monoclonal Ig has been exceptionally described as the cause of membranoproliferative glomerulonephritis, through activation of the complement alternative pathway (CAP).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We retrospectively studied six adults with monoclonal gammopathy and glomerulonephritis (GN) characterized by isolated C3 deposits.

RESULTS

All patients presented with hematuria, associated with chronic renal failure and proteinuria in five patients, three of whom had nephrotic syndrome. Five patients had monoclonal gammopathy of undetermined significance and one had smoldering myeloma. The serum monoclonal IgG (κ four of six, λ two of six) was associated with light chain (LC) proteinuria in five patients. Four patients had low serum C3 and/or factor B levels. C4, factor H (CFH), and I protein levels were normal in five of five patients; none had detectable C3NeF. IgG anti-CFH activity was positive in one case. No mutations in CFH, CFI, and MCP genes were identified in four of four patients. Deposits were intramembranous, subepithelial, and mesangial by electron microscopy, and stained positive for C3 (six of six), properdin, and CFH (two of two) but negative for Ig LC and heavy chains, C4, and C1q (6/6) by immunofluorescence. Five patients progressed to end-stage renal disease over a median period of 47 months, despite chemotherapy in four patients. In one patient, monoclonal λLC deposits were observed on a follow-up kidney biopsy after 4 years.

CONCLUSIONS

GN with isolated glomerular C3 deposits might represent an unusual complication of plasma cell dyscrasia, related to complement activation through an autoantibody activity of the monoclonal Ig against a CAP regulator protein.

Recurrent glomerular disease after kidney transplantation

PURPOSE OF REVIEW

Recurrent glomerulonephritis is the third most common cause of graft failure, ranking only behind immunologic rejection and death with a functioning graft. Knowledge of the rates and timing of recurrent glomerular disease are important in counseling potential transplant recipients and preventive and therapeutic treatment strategies are necessary for those patients at risk.

RECENT FINDINGS

Large observational studies that have analyzed posttransplant biopsies have confirmed the high rates of glomerular disease recurrence in renal allografts. Newer immunosuppressive protocols over the past 10 years have not affected the rate of disease recurrence or graft loss. There is emerging evidence that rituximab may be efficacious in treating recurrent membranous nephropathy and focal segmental glomerulosclerosis; however, larger clinical trials are warranted.

SUMMARY

Recurrent glomerulonephritis is an important determinant of long-term outcomes after transplantation, requiring appropriate counseling to potential transplant recipients. Currently, there are no proven strategies to prevent recurrent glomerulonephritis in renal transplant recipients. Despite the high rates of recurrent disease, long-term graft survival is still very good and transplantation remains the best treatment option for patients with end-stage renal disease from primary glomerulonephritis.

Allograft failure in kidney transplant recipients with membranoproliferative glomerulonephritis

BACKGROUND

Membranoproliferative glomerulonephritis types I (MPGN-I) and II (MPGN-II) are rare diseases that in limited case series have been reported to recur frequently in kidney transplants and have a negative impact on allograft survival.

STUDY DESIGN

Retrospective database review.

SETTING & PARTICIPANTS

189,211 primary kidney transplants in the United Network for Organ Sharing (UNOS) database from September 1987 to May 2007.

PREDICTOR OR FACTOR

MPGN-I (811 patients; 0.4%), MPGN-II (179 patients; 0.1%), other GN (58,129 patients; 30.7%), and all other diagnoses (130,092 patients; 68.7%).

OUTCOMES

Death-censored and non-death-censored allograft survival.

RESULTS

Compared with controls, patients with MPGN-I and MPGN-II were significantly younger at the time of transplant, with a median age of 36 and 27 years compared with 44 years in the GN group and 46 years in all other disease groups, respectively (all P < 0.001). Mortality in patients with MPGN-I (8.8%) was significantly lower compared with the GN (11.3%; P = 0.02) and other disease (16.6%; P < 0.001) populations and lower in those with MPGN-II (9.5%) compared with the other disease (16.6%; P = 0.01) population. Graft failure rates were significantly higher in the MPGN-I (44.5%) cohort, but not in the MPGN-II (45.3%) cohort compared with the GN (38.0%) population (P < 0.001 and P = 0.05, respectively); neither MPGN cohort differed from the other disease (43.0%) population (P = 0.4 and P = 0.5). Overall, 10-year death-censored graft survival was similar for MPGN-I (56.2%) and MPGN-II (57.5%); both were significantly worse than for GN (65.2%; P < 0.001 and P = 0.003, respectively), and only MPGN-I was significantly worse than the other disease (60.0%) population (P = 0.004). Of allograft failures with a reported cause, disease recurrence was the primary cause in 36 (14.5%) MPGN-I and 18 (29.5%) MPGN-II transplant recipients and was significantly higher compared with 879 (6.6%) GN and 1,319 (4.4%) all-other-disease recurrence failures (P < 0.001).

LIMITATIONS

Limited pretransplant clinical and biopsy data.

CONCLUSIONS

A diagnosis of MPGN-I or MPGN-II has a significant negative impact on overall primary allograft survival compared with other forms of glomerulonephritis, whereas only MPGN-I has a significant, but modest, negative effect compared with other causes of end-stage renal disease.

Posttransplant recurrence of primary glomerulonephritis

All forms of primary GN may recur after kidney transplantation and potentially jeopardize the survival of the graft. IgA nephritis (IgAN) may recur in approximately one third of patients, more frequently in younger patients and in those with a rapid progression of the original disease. However, with the exception of few patients with rapid progression, there is no evidence that recurrence of IgAN has a deleterious effect on graft survival at least up to 10 years. Recurrence of focal segmental glomerulosclerosis (FSGS) is often associated with nephrotic proteinuria and is more frequent in children, in patients with rapid progression of the original disease, and in those who lost a previous transplant from recurrence. The natural course of recurrent FSGS is usually unfavorable. Early and intensive plasmapheresis may obtain complete or partial response in several patients. Good results have also been reported with rituximab. Idiopathic membranous nephropathy (IMN) may recur in 30% to 40% of patients. The graft survival in patients with IMN is not different than that of patients with other renal diseases. Good results with rituximab have been reported. Membranoproliferative GN (MPGN) may recur in 27% to 65% of patients. The recurrence is more frequent and the prognosis is more severe in type II MPGN. Although recurrent GN is relatively frequent and may worsen the outcome of renal allografts in some patients, its effect is diluted by several other risk-factors that may have a greater effect than recurrent GN on the long-term graft survival.

Proliferative glomerulonephritis with monoclonal IgG deposits recurs in the allograft

BACKGROUND AND OBJECTIVES

Proliferative GN with monoclonal IgG deposits (PGNMID) is a newly described entity resembling immune complex GN. Its potential to recur in the allograft is undefined.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The first cases of recurrent PGNMID in the allograft are reported.

RESULTS

The cohort includes four Caucasians (3 women, 1 man) with a mean age 58.5 years. No patient had M spike or hematologic malignancy. Recurrence was first documented by biopsy at a mean of 3.8 months posttransplant for indications of renal insufficiency in four patients, proteinuria in three patients, and microhematuria in three patients. Monoclonal IgG deposits (3 IgG3κ and 1 IgG3λ) in the transplants had identical heavy- and light-chain isotypes as in the native kidneys. In two patients, a pattern of endocapillary GN was identified in the native and transplant biopsies, whereas two patients with membranoproliferative GN in the native kidney developed endocapillary or mesangial GN in the transplant. Recurrence was treated with combined high-dose prednisone plus rituximab (n = 3) or plus cyclophosphamide (n = 1). After a mean posttransplant follow-up of 43 months, all four patients achieved reduction in proteinuria and three had reduction in creatinine. Repeat biopsies showed reduced histologic activity after treatment.

CONCLUSIONS

PGNMID can recur in the transplant despite the absence of a serum M spike. Recurrence is heralded by proteinuria, hematuria, and allograft dysfunction and manifests diverse histologic patterns. Although the pathogenesis remains unknown, early immunosuppressive therapy appears to stabilize the course.

Membranoproliferative glomerulonephritis secondary to monoclonal gammopathy

BACKGROUND AND OBJECTIVES

Membranoproliferative glomerulonephritis (MPGN) is an immune complex-mediated glomerulonephritis characterized by subendothelial and mesangial deposition of immune complexes. Autoimmune diseases and chronic infections, such as hepatitis C, are commonly recognized causes of MPGN; however, monoclonal gammopathy is a less widely recognized cause of MPGN.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We reviewed all renal biopsies of MPGN in Mayo Clinic patients during a 6-year period to determine the association of monoclonal gammopathy with MPGN. Results were correlated with electrophoresis studies and bone marrow biopsies to clarify the relationship between MPGN and gammopathies.

RESULTS

Of 126 patients with MPGN, 20 did not have workup for hepatitis B or C. Of the remaining 106 patients, 25 (23.5%) were positive for hepatitis B or C. Of the 81 hepatitis-negative patients, 13 were not evaluated for gammopathies. Of the remaining 68 patients, 28 (41.1%) had serum and/or urine electrophoresis studies positive for monoclonal gammopathy. Serum immunofixation electrophoresis was the most sensitive method for diagnosing monoclonal gammopathy. Renal biopsy showed a membranoproliferative pattern of injury; immunofluorescence microscopy was often instrumental in diagnosing the underlying gammopathy. On the basis of the bone marrow biopsy, monoclonal gammopathy of undetermined significance was the most common entity associated with MPGN. Other, less common causes included multiple myeloma, low-grade B cell lymphoma, and chronic lymphocytic leukemia.

CONCLUSIONS

Monoclonal gammopathy is an important and common cause of MPGN; therefore, all patients with a diagnosis of MPGN should be evaluated for an underlying monoclonal gammopathy.