The natural history of immunoglobulin M nephropathy in adults

Glomerulonephritis and inflammatory bowel disease: A tale of gut-kidney axis dysfunction

The incidence and prevalence of Inflammatory Bowel Disease (IBD) has increased over the past decades, imposing a growing socioeconomic burden on healthcare systems globally. Most of the morbidity and mortality related to IBD is typically attributed to gut inflammation and its complications; yet the disease is characterized by various extraintestinal manifestations that can be severe. Glomerulonephritis (GN) is of particular interest since a significant proportion of patients evolve into end-stage kidney disease, requiring kidney replacement therapy and associated with high morbidity and mortality. Herein, we review the GN landscape in IBD and define the clinical and pathogenic associations reported to date in the literature. Underlying pathogenic mechanisms suggest either the initiation of antigen-specific immune responses in the inflamed gut that cross react with non-intestinal sites, such as the glomerulus, or that extraintestinal manifestations are gut-independent events that occur due to an interaction between common genetic and environmental risk factors. We present data associating GN with IBD either as a bona fide extraintestinal manifestation or reporting it as an extraneous co-existing entity, involving various histological subtypes, such as focal segmental glomerulosclerosis, proliferative GN, minimal change disease, crescentic GN, but most emphatically IgA nephropathy. Supporting the pathogenic interplay between gut inflammation and intrinsic glomerular processes, enteric targeting the intestinal mucosa with budesonide reduced IgA nephropathy-mediated proteinuria. Elucidating the mechanisms at play would provide insight not only into IBD pathogenesis but also into the gut's role in the development of extraintestinal diseases, such as glomerular diseases.

The Immune System and Idiopathic Nephrotic Syndrome

Idiopathic nephrotic syndrome often responds to immunosuppressive treatment. Nevertheless, this syndrome-and the drugs used to treat it-remain important causes of patient morbidity. Idiopathic nephrotic syndrome is usually caused by minimal change disease or FSGS, diseases that primarily affect the podocytes. In spite of decades of research, the underlying causes of both diseases remain incompletely understood. There is, however, a large body of observational and experimental data linking the immune system with both minimal change disease and FSGS, including associations with systemic infections and hematologic malignancies. Perhaps most compellingly, many different immunomodulatory drugs are effective for treating idiopathic nephrotic syndrome, including biologic agents that have well-defined immune targets. In fact, the unexpected efficacy of targeted therapeutic agents has provided important new insights into the pathogenesis of these diseases. Given the large number of drugs that are available to deplete or block specific cells and molecules within the immune system, a better understanding of the immunologic causes of idiopathic nephrotic syndrome may lead to better diagnostic and therapeutic approaches.

Pathological and Evolutive Correlations in Steroid Resistant Nephrotic Syndrome in Children

Background

Nephrotic syndrome (NS) is the term used for the association of edema and massive proteinuria. From a therapeutic point of view, it is important to distinguish between primitive and secondary kidney damage. The clinical evolution, prognosis and therapeutic response in the NS in children are directly determined by the anatomopathological aspect. Steroid resistant nephrotic syndrome was diagnosed in patients with idiopathic NS based on lack of complete remission despite treatment with steroids.

Purpose

To analyse the anatomopathological aspects of steroid resistant nephrotic syndrome (SRNS) and their correlation with evolution.

Materials and Methods

We made a retrospective study with the aim to analyze the anatomo-pathological aspects and their correlations with evolution in 68 cases of steroid resistant nephrotic syndrome (SRNS) hospitalized in the Pediatric Nephrology Department in Iaşi, Romania. We defined SRNS in all cases without response to corticosteroids after the first month of therapy. For all the cases selected, the period of follow-up was the minimal 6 months.

Results and Discussions

A 36% case of nephrotic syndrome was corticoresistant, with the mean age at onset of patients with SRNS being 9.18 years, compared to KDIGO studies in which the corticosteroid resistance is 10–20%. Renal biopsy was performed in 80.88% children with SRNS and was allowed the evaluation of the activity and chronicity index. Total remission was obtained in 44.01% children with SRNS. The correlation of the anatomopathological aspects with the evolution is not statistically significant (p = 0.76), observing different therapeutic responses to all the analyzed histological types.

Conclusion

Almost half of NS in children are cortico resistant. Remission was obtained in 44% of cases of SRNS. Predicting the response to long-term treatment in SRNS is difficult using only renal biopsy; it is necessary to introduce genetic molecular analyses to establish a judicious therapeutic attitude.

Development of Immunoglobulin M Nephropathy in a Pregnant Woman

Immunoglobulin M nephropathy (IgMN) is a glomerular disease that may be identified in all age groups, but children and young adults appear to have been affected more frequently in some series. The clinical picture could differ from hematuria to rapidly progressive glomerulonephritis. The main characteristics in pathologic examination are mesangial hypercellularity with a diffuse and granular immunoglobulin M deposition in the glomerular structure. To date, a standardized protocol has not been proposed for IgMN treatment. Systemic corticosteroids, calcineurin inhibitors, cyclophosphamide, and rituximab were agents reported in the literature. We present a 30-year-old woman admitted to the hospital for edema in the lower extremities at the 31st week of pregnancy. She had one abortus previously, and this was her second pregnancy. Renal biopsy performed after delivery was reported as IgMN with mesangial proliferation. She received 1 mg/kg/day prednisone therapy achieving complete remission. This report is the first case of IgMN developed in pregnancy.

Renal Outcome of IgM Nephropathy: A Comparative Prospective Cohort Study

Immunoglobulin M nephropathy (IgMN) is an idiopathic glomerulonephritis characterized by diffuse deposits of IgM in the glomerular mesangium. However, its renal prognosis remains unknown. We compared renal outcomes of IgMN patients with those of patients with minimal change disease (MCD), focal segmental glomerulosclerosis (FSGS), or mesangial proliferative glomerulonephritis (MsPGN) from a prospective observational cohort, with 1791 patients undergoing native kidney biopsy in eight hospitals affiliated with The Catholic University of Korea between December 2014 and October 2020. IgMN had more mesangial proliferation and matrix expansion than MsPGN and more tubular atrophy and interstitial fibrosis than MCD. IgMN patients had decreased eGFR than MCD patients in the earlier follow-up. However, there was no significant difference in urine protein or eGFR among all patients at the last follow-up. When IgMN was divided into three subtypes, patients with FSGS-like IgMN tended to have lower eGFR than those with MCD-like or MsPGN-like IgMN but higher proteinuria than MsPGN-like IgMN without showing a significant difference. The presence of hypertension at the time of kidney biopsy predicted ≥20% decline of eGFR over two years in IgMN patients. Our data indicate that IgMN would have a clinical course and renal prognosis similar to MCD, FSGS, and MsPGN.

Late relapse of IgM nephropathy-associated nephrotic syndrome after repeated administration of immune checkpoint inhibitor against pulmonary adenocarcinoma

ICPIs were effective for primary and metastatic foci of lung adenocarcinoma, but their repeated use provoked a late relapse of IgM nephropathy and lethal lesions in pancreas and lung. ICPIs should be used carefully in cases of immune-related disease.

IgM nephropathy complicated by cerebral venous sinus thrombosis: a case study

Background

IgM nephropathy is a rare disease with variable clinical presentations and is an unusual cause of nephrotic syndrome. Histopathological findings typically include mesangial hypercellularity with IgM and complement deposition, though the spectrum may range from normal glomeruli through to focal and segmental glomerulosclerosis. Thromboembolism is a well recognised complication of nephrotic syndrome, but cerebral venous sinus thrombosis is rarely described.

Case presentation

This is the case of a 23-year-old male presenting with the nephrotic syndrome, whose initial renal biopsy was consistent with minimal change disease. Complete remission was achieved with prednisone, however multiple relapses and steroid dependence prompted re-biopsy, the results of which were more consistent with IgM nephropathy. His last relapse was complicated by cerebral venous sinus thrombosis. He then received rituximab and a weaning course of prednisone to again enter remission.

Conclusions

This case highlights the need to consider IgM nephropathy in the differential diagnosis of nephrotic syndrome. Additionally, it emphasises the risk of thrombosis in patients with severe nephrosis.

Successful treatment of a rare variant of mesangioproliferative glomerulonephritis with IgM deposits with Cyclosporin A

We present a case with a rare variant of glomerulonephritis, IgM nephropathy, which occurs mainly with nephrotic syndrome. The clinical features of this variant of kidney damage are characterized; the pathogenetic and the transformation of this form of nephritis into focal segmental glomerulosclerosis are discussed. The development of severe nephrotic syndrome at the beginning of the disease, the formation of secondary steroid resistance have confirmed this hypothesis and have justified the treatment with cyclosporin A aimed at the recovery of the function of the podocyte with remission of nephritis.

A case report of immunoglobulin M nephropathy manifesting as crescentic glomerulonephritis and nephrotic syndrome in an adult

Background

The nature of immunoglobulin M (IgM) nephropathy has been controversial for a long time, but it is now considered an independent disease like immunoglobulin A nephropathy. IgM nephropathy has been known to have various clinical manifestations ranging from asymptomatic hematuria and/or proteinuria to nephrotic syndrome. Recently, one case of IgM nephropathy manifesting as crescentic glomerulonephritis (GN) was reported in a child.

Case presentation

We experienced a case of IgM nephropathy that manifested clinically as nephritic and nephrotic syndrome with pathologically confirmed crescentic GN in a 30-year-old woman. We administered a calcineurin inhibitor and corticosteroids to treat the ongoing nephrotic syndrome after remission of crescentic GN. As a result, her proteinuria was significantly reduced and edema improved.

Conclusions

We described a case of IgM nephropathy in an adult patient who initially developed crescentic GN with nephritic and nephrotic syndrome. This case report could contribute to a deeper understanding of IgM nephropathy.

Epidemiology and Pathophysiology of Glomerular C4d Staining in Native Kidney Biopsies

Introduction

Routine C4d staining in renal transplantation has stimulated its use in kidney biopsies with glomerulonephritis (GN). Methodical description on staining patterns in the native kidney is not available.

Methods

We retrospectively evaluated C4d staining in formalin-fixed paraffin-embedded sections from 519 native kidney biopsies (bx) with and without glomerular disease.

Results

Strong C4d staining was consistently present in immune-complex GN, including lupus nephritis (LN) (n = 68), membranous GN (n = 24), membranoproliferative glomerulonephritis (MPGN) pattern (n = 22), fibrillary GN (n = 3), and proliferative GN with monoclonal IgG (n = 3). C4d stained all cases of postinfectious GN (n = 7) amyloidosis (n = 20) and C1q GN (n = 3). In contrast, IgA nephropathy (IgAN) (n = 34), was negative in 62% of bx, with the rest staining variably. The E1 Oxford classification score correlated with capillary wall C4d staining (P = 0.05). C4d marked the glomerular and arteriolar lesions in thrombotic microangiopathy (TMA; n = 16), the glomerular sclerotic segments in focal segmental glomerulosclerosis (FSGS; n = 77), and marked areas of necrosis in crescentic GN (n = 21). In diabetic glomerulopathy (n = 70), C4d marked advanced insudative lesions but was negative otherwise. C4d weakly stained the mesangium, or was negative in normal biopsies (n = 13), minimal change disease (MCD; n = 21), thin basement membrane disease (n = 20), Alport (n = 3), IgM nephropathy (n = 2), C3 glomerulopathy (n = 5), acute interstitial nephritis (n = 12), acute tubular necrosis (n = 22), ischemic glomerulopathy/nephrosclerosis (n = 23), and other miscellaneous processes (n = 14). Staining in tubular basement membranes and peritubular capillaries was most common in lupus.

Conclusion

Based on reliable staining in lupus and membranous GN, C4d staining is potentially useful as a screening and diagnostic tool, if only paraffin-embedded tissue is available. Knowledge of C4d staining patterns in normal and pathological tissues enhances its diagnostic value.

Immunoglobulin M Nephropathy in a Patient with Wilson's Disease

Immunoglobulin M nephropathy (IgMN) is characterized by the deposition of immunoglobulin M in a dominant distribution in the renal glomeruli. Primary immunoglobulin M nephropathy is diagnosed after consistent light microscopy (LM), immunofluorescence (IF), electron microscopy (EM) results, and exclusion of known systemic disorders causing immunoglobulin M deposition in the glomeruli. The secondary disease has been reported with a few conditions though it has never been reported with any primary disease of the liver. We report the case of an adolescent male patient who presented with nausea, vomiting, diarrhea, and worsening anasarca. He was found to have nephrotic-range proteinuria that did not respond to conventional corticosteroid treatment. He was subjected to a renal biopsy which revealed a diagnosis of immunoglobulin M nephropathy. His liver function tests were deranged and an ultrasound scan of the abdomen revealed a coarse irregular liver. Workup revealed elevated urine copper excretion and a low ceruloplasmin level. He was diagnosed as a case of Wilson's disease and started on penicillamine and pyridoxine. He was also started on intravenous cyclophosphamide for the corticosteroid-resistant nephrotic syndrome to which he responded remarkably well. His edema settled, proteinuria resolved, and liver functions normalized. Currently, he is in remission and enjoying good health. To the best of our knowledge, we report the first known association between IgM nephropathy and Wilson's disease. It is presently not clear if causation can necessarily be established. This may be the result of defective IgM clearance by the liver or an altered metabolism of the antibody or immune complexes, as with hepatic-associated immunoglobulin M (IgM) nephropathy. Further studies are needed to elucidate the exact mechanism of this disease.