Coincident membranous glomerulonephritis and chronic inflammatory demyelinating polyradiculoneuropathy: Questioning the autoimmunity hypothesis

CIDP/autoimmune nodopathies with nephropathy: a case series study

OBJECTIVE

The co-morbidity of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP)/autoimmune nodopathies with nephropathy has been gradually known in recent years. This study was intended to explore the clinical, serological and neuropathological features of seven patients with CIDP/autoimmune nodopathies and nephropathy.

METHODS

Among 83 CIDP patients, seven were identified with nephropathy. Their clinical, electrophysiological and laboratory examination data were collected. The nodal/paranodal antibodies were tested. The sural biopsies were performed in all the patients, and renal biopsies were operated in 6 patients.

RESULTS

Six patients had chronic onsets and one had an acute onset. Four patients exhibited peripheral neuropathy preceding nephropathy while two showed concurrent onset of neuropathy and nephropathy, and one started with nephropathy. All the patients showed demyelination in electrophysiological examination. Nerve biopsies showed mild to moderate mixed neuropathies including demyelinating and axonal changes in all patients. Renal biopsies showed membranous nephropathy in all 6 patients. Immunotherapy was effective in all patients, with two patients showing good response to corticosteroid treatment alone. Four of the patients were positive to anti-CNTN1 antibody. Compared with anti-CNTN1 antibody-negative patients, antibody-positive patients had a higher proportion of ataxia (3/4 vs. 1/3), autonomic dysfunction (3/4 vs. 1/3), less frequent antecedent infections (1/4 vs. 2/3), higher cerebrospinal fluid proteins (3.2 g/L vs. 1.69 g/L), more frequent conduction block on electrophysiological examination (3/4 vs. 1/3), higher myelinated nerve fiber density, and positive CNTN1 expression in the glomeruli of kidney tissues.

CONCLUSION

Anti-CNTN1 antibody was the most frequent antibody in this group of patients with CIDP/autoimmune nodopathies and nephropathy. Our study suggested that there might be some clinical and pathological differences between the antibody positive and negative patients.

Characteristics of Anti-Contactin1 Antibody-Associated Autoimmune Nodopathies With Concomitant Membranous Nephropathy

Background

The concurrence of anti-contactin 1 (CNTN1) antibody-associated chronic inflammatory demyelinating polyneuropathy (CIDP) and membranous nephropathy (MN) has previously been reported in the literature. CIDP with autoantibodies against paranodal proteins are defined as autoimmune nodopathies (AN) in the latest research. In view of the unclear relationship between CIDP and MN, we performed a case study and literature review to investigate the clinical characteristics of anti-CNTN antibody-associated AN with MN.

Methods

We detected antibodies against NF155, NF186, CNTN1, CNTN2, CASPR1 and PLA2R in blood samples of a patient with clinically manifested MN and concomitant peripheral neuropathy via double immunofluorescence staining and conducted a quantitative measurement of anti-PLA2R IgG antibodies via enzyme-linked immunosorbent assay (ELISA). Case reports of anti-CNTN1 antibody-associated AN, anti-CNTN1 antibody-associated AN with MN, and CIDP with MN were retrieved through a literature search for a comparative analysis of clinical characteristics. The cases were grouped according to the chronological order of CIDP and MN onset for the comparison of clinical characteristics.

Results

A 57-year-old man with anti-PLA2R positive MN was admitted to the hospital due to limb numbness, weakness, and proprioceptive sensory disorder. He was diagnosed with anti-CNTN1 antibody-associated AN and recovered well after immunotherapy. Our literature search returned 22 cases of CIDP with MN that occurred before, after, or concurrently with CIDP. Good responses were achieved with early single-agent or combination immunotherapy, but eight out of the 22 patients with CIDP and concomitant MN ultimately developed different motor sequelae. Five patients had anti-CNTN1 antibody-associated AN with MN. Among these patients, males accounted for the majority of cases (male:female=4:1), the mean age at onset was late (60.2 ± 15.7 years, range 43–78 years), and 40% had acute to subacute onset. Clinical manifestations included sensory-motor neuropathy, sensory ataxia caused by proprioceptive impairment, and elevated cerebrospinal fluid protein levels.

Conclusion

The age at onset of CIDP with MN was earlier than that of anti-CNTN1 antibody-associated AN. MN may occur before, after or concurrently with CIDP. The early detection and isotyping of anti-CNTN1 and anti-PLA2R antibodies and the monitoring of isotype switching may be essential for suspected CIDP patients.

Mechanisms of Primary Membranous Nephropathy

Membranous nephropathy (MN) is an autoimmune disease of the kidney glomerulus and one of the leading causes of nephrotic syndrome. The disease exhibits heterogenous outcomes with approximately 30% of cases progressing to end-stage renal disease. The clinical management of MN has steadily advanced owing to the identification of autoantibodies to the phospholipase A2 receptor (PLA2R) in 2009 and thrombospondin domain-containing 7A (THSD7A) in 2014 on the podocyte surface. Approximately 50–80% and 3–5% of primary MN (PMN) cases are associated with either anti-PLA2R or anti-THSD7A antibodies, respectively. The presence of these autoantibodies is used for MN diagnosis; antibody levels correlate with disease severity and possess significant biomarker values in monitoring disease progression and treatment response. Importantly, both autoantibodies are causative to MN. Additionally, evidence is emerging that NELL-1 is associated with 5–10% of PMN cases that are PLA2R- and THSD7A-negative, which moves us one step closer to mapping out the full spectrum of PMN antigens. Recent developments suggest exostosin 1 (EXT1), EXT2, NELL-1, and contactin 1 (CNTN1) are associated with MN. Genetic factors and other mechanisms are in place to regulate these factors and may contribute to MN pathogenesis. This review will discuss recent developments over the past 5 years.

Anti-Neurofascin-Associated Nephrotic-Range Proteinuria in Chronic Inflammatory Demyelinating Polyneuropathy

There are few case reports of concomitant chronic inflammatory demyelinating polyneuropathy (CIDP) and focal segmental glomerulosclerosis. A rare autoantibody to a neuronal and podocyte structural component, neurofascin, may be contributory. A Black man in his 40s presented with worsening polyneuropathy requiring mechanical ventilation and initially acute inflammatory demyelinating polyneuropathy was diagnosed. After a poor response to intravenous immunoglobulin, plasmapheresis was initiated. The patient also had concomitant new-onset nephrotic-range proteinuria. A limited kidney biopsy was interpreted as minimal change disease and was treated with prednisone. After some improvement, the patient was extubated; however, he later re-presented with worsening symptoms requiring mechanical ventilation and was re-treated with plasmapheresis. Due to the protracted course and poor response to intravenous immunoglobulin, acute-onset CIDP was diagnosed and a neuromuscular antibody workup returned positive for neurofascin, supporting the diagnosis of seropositive acute-onset CIDP. A repeat kidney biopsy demonstrated focal segmental glomerulosclerosis and acute tubular damage. The patient was treated with steroids and tacrolimus and later transitioned to rituximab. Neurofascin enzyme-linked immunosorbent assay then tested negative with concomitant resolution of both neuropathy and proteinuria. Further studies will help validate these findings and the treatment strategy.

Chronic Inflammatory Demyelinating Polyneuropathy With Concurrent Membranous Nephropathy: An Anti-paranode and Podocyte Protein Antibody Study and Literature Survey

Background: Several case reports have described the concurrence of chronic inflammatory demyelinating polyneuropathy (CIDP) and membranous nephropathy (MN). The presence of autoantibodies against podocyte antigens phospholipase A2 receptor (PLA2R) and thrombospondin type 1 domain containing 7A (THSD7A) in MN suggests an autoimmune mechanism. Some CIDP patients also harbor autoantibodies against paranodal proteins such as neurofascin 155 (NF155) and contactin-1 (CNTN1). We investigated the relationship between CIDP and MN by assaying autoantibodies against paranodal and podocyte antigens in a CIDP patient with MN, and by a literature survey on the clinical features of CIDP with MN.

Methods: Anti-CNTN1 and NF155 antibodies were measured by flow cytometry using HEK293 cell lines stably expressing human CNTN1 or NF155. Binding capacity of antibodies was validated by immunostaining mouse teased sciatic nerve fibers. Anti-PLA2R antibodies were measured by enzyme-linked sorbent assay and anti-THSD7A antibodies by indirect immunofluorescence assay. Clinical features between 14 CIDP with MN cases including two with anti-CNTN1 antibodies and 20 anti-CNTN1 antibody-positive CIDP cases were compared.

Results: A patient whose ages was in the late 70 s complained of progressive weakness and superficial and deep sensory impairment in four extremities over 6 months. Nerve conduction studies showed prominent demyelination patterns. The patient presented with nephrotic syndrome. Renal biopsy disclosed basement membrane thickening with local subepithelial projections and glomerular deposits of IgG4, compatible with MN. Autoantibody assays revealed the presence of IgG4 and IgG1 anti-CNTN1 antibodies, but an absence of anti-NF155, anti-PLA2R, and anti-THSD7A antibodies. The patient's serum stained paranodes of teased sciatic nerves. CIDP with MN and anti-CNTN1 antibody-positive CIDP commonly showed male preponderance, relatively higher age of onset, acute to subacute onset in 35–50% of cases, distal dominant sensorimotor neuropathy, proprioceptive impairment leading to sensory ataxia, and very high cerebrospinal fluid protein levels. However, 11 of 13 CIDP patients with MN had a favorable response to mono- or combined immunotherapies whereas anti-CNTN1 antibody-positive CIDP was frequently refractory to corticosteroids and intravenous immunoglobulin administration.

Conclusion: CIDP with MN and anti-CNTN1 antibody-positive CIDP show considerable overlap but are not identical. CIDP with MN is probably heterogeneous and some cases harbor anti-CNTN1 antibodies.

Autoantibodies to nodal isoforms of neurofascin in chronic inflammatory demyelinating polyneuropathy

Chronic inflammatory demyelination polyneuropathy is a heterogeneous and treatable immune-mediated disorder that lacks biomarkers to support diagnosis. Recent evidence indicates that paranodal proteins (contactin 1, contactin-associated protein 1, and neurofascin-155) are the targets of autoantibodies in subsets of patients showing distinct clinical presentations. Here, we identified neurofascin-186 and neurofascin-140 as the main targets of autoantibodies in five patients presenting IgG reactivity against the nodes of Ranvier. Four patients displayed predominantly IgG4 antibodies, and one patient presented IgG3 antibodies that activated the complement pathway in vitro. These patients present distinct clinical features compared to those with anti-neurofascin-155 IgG4. Most patients had a severe phenotype associated with conduction block or decreased distal motor amplitude. Four patients had a subacute-onset and sensory ataxia. Two patients presented with nephrotic syndromes and one patient with an IgG4-related retroperitoneal fibrosis. Intravenous immunoglobulin and corticosteroids were effective in three patients, and one patient remitted following rituximab treatment. Clinical remission was associated with autoantibody depletion and with recovery of conduction block and distal motor amplitude suggesting a nodo-paranodopathy. Our data demonstrate that the pathogenic mechanisms responsible for chronic inflammatory demyelination polyneuropathy are broad and may include dysfunctions at the nodes of Ranvier in a subgroup of patients.

Steroid-responsive polyradiculopathy in association with focal segmental glomerulosclerosis

An 80-year-old woman presented with simultaneous increasing muscle weakness and nephrotic syndrome. A renal biopsy confirmed focal segmental glomerulosclerosis (FSGS). Her neurological diagnosis best fitted with a Guillain-Barre-like syndrome. There have been several cases of FSGS in combination with both conventional and atypical Guillain-Barre syndrome (GBS). Our patient was treated with high-dose steroids and resolution of both nephrotic syndrome and neurological symptoms occurred over 6 months. This article reviews all previously published presentations of this nature and discusses putative mechanisms for the development of concurrent FSGS and GBS.

European Federation of Neurological Societies/Peripheral Nerve Society guideline on management of chronic inflammatory demyelinating polyradiculoneuropathy: report of a joint task force of the European Federation of Neurological Societies and the Peripheral Nerve Society - first revision

BACKGROUND

Consensus guidelines on the definition, investigation, and treatment of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) have been previously published in European Journal of Neurology and Journal of the Peripheral Nervous System.

OBJECTIVES

To revise these guidelines.

METHODS

Disease experts, including a representative of patients, considered references retrieved from MEDLINE and Cochrane Systematic Reviews published between August 2004 and July 2009 and prepared statements that were agreed in an iterative fashion.

RECOMMENDATIONS

The Task Force agreed on Good Practice Points to define clinical and electrophysiological diagnostic criteria for CIDP with or without concomitant diseases and investigations to be considered. The principal treatment recommendations were: (i) intravenous immunoglobulin (IVIg) (Recommendation Level A) or corticosteroids (Recommendation Level C) should be considered in sensory and motor CIDP; (ii) IVIg should be considered as the initial treatment in pure motor CIDP (Good Practice Point); (iii) if IVIg and corticosteroids are ineffective, plasma exchange (PE) should be considered (Recommendation Level A); (iv) if the response is inadequate or the maintenance doses of the initial treatment are high, combination treatments or adding an immunosuppressant or immunomodulatory drug should be considered (Good Practice Point); (v) symptomatic treatment and multidisciplinary management should be considered (Good Practice Point).