Virus discovery in chronic inflammatory demyelinating polyneuropathy

The events triggering and/or sustaining the auto-immune response underlying chronic inflammatory demyelinating polyneuropathy (CIDP) are unknown. Similar to Guillain-Barré syndrome (GBS), a viral infection might play a role in CIDP. In this study, an virus detection method (VIDISCA-next generation sequencing) capable of detecting known and unknown viruses, was used to analyze the virome in serum of 47 CIDP patients at different time points of the disease and, when available, in cerebrospinal fluid (CSF) samples (N: 17). Serum samples of GBS patients (N:24) and healthy controls (N:114) were used for comparisons. In 5/47 (10.6%; 95% CI: 4-23) CIDP samples, 10/24 (42%; 95% CI: 22-63) GBS samples and 32/114 (28.1%; 95% CI: 20-37) healthy controls samples, anelloviruses were detected, generally regarded as a non-pathogenic species. Parvovirus B19 and GB virus C were found in two CIDP samples (4%). Parvovirus B19, HIV-1 and GB virus C were found in three GBS samples (13%). In 2/17 CIDP CSF samples, an anellovirus and polyomavirus were detected, probably due to contamination during lumbar puncture. No sequences of other viruses were detected in serum or CSF. A (persistent) viral infection sustaining the auto-immune response in CIDP seems therefore unlikely.

Relapsing/remitting type 1 diabetes

AIMS/HYPOTHESIS

Type 1 diabetes is believed to be an autoimmune disease associated with irreversible loss of insulin secretory function that follows a chronic progressive course. However, it has been speculated that relapsing/remitting disease progression may occur in type 1 diabetes.

METHODS

We report the case of an 18-year-old girl with Graves' disease, chronic inflammatory demyelinating polyneuropathy (CIDP) and multiple islet autoantibodies, presenting with relapsing/remitting hyperglycaemia. Peripheral blood mononuclear cells were analysed for islet autoimmunity.

RESULTS

There were two instances of hyperglycaemia relapse during CIDP flare-ups that required insulin therapy and remitted after i.v. immunoglobulin (IVIG) therapy improving neurological symptoms. A diagnosis of type 1 diabetes was assigned on the basis of insulin need, HbA_1c and islet autoantibodies. Insulin requirements disappeared following IVIG treatment and peaked during CIDP flare-ups. Pro- and anti-inflammatory cytokine responses were noted against islet autoantigens.

CONCLUSIONS/INTERPRETATION

We provide clinical evidence of relapsing/remitting type 1 diabetes associated with IVIG treatment and the regulation of islet autoimmunity. Despite sufficient residual beta cell mass, individuals can experience episodes of impaired glycaemia control. This disconnect between beta cell mass and function highlighted by our case may have implications for the use of beta cell function as the primary endpoint for immune intervention trials aiming to protect beta cell mass rather than function. Immune modulation may restore beta cell function and glycaemic control.

Monoclonal gammopathy of undeterminated significance and endoneurial IgG deposition: A case report

BACKGROUND

Monoclonal gammopathy of undeterminated significance is the most common form of plasma cell dyscrasia, usually considered as benign. In rare cases it may have a malignant course, sometimes limited to an organ such as peripheral nerves.

METHODS

We describe clinical, electrophysiological and pathological findings in a patient presenting a immunoglobulin G (IgG) paraproteinemic polyneuropathy clinically mimicking a chronic inflammatory demyelinating polyneuropathy.

RESULTS

Immuno-electron microscopy (immune-EM) demonstrated that the widenings of the myelin lamellae resulted from the infiltration of IgG between a significant number of myelin lamellae (with absence of inflammatory cells in the epineurium, endoneurium, and perineurium, and the lack signs of vasculitis). This patient was finally treated successfully with lenalidomide then mycophenolate mofetil.

CONCLUSIONS

In polyneuropathies associated to a monoclonal gammopathy, a nerve biopsy may clinch the diagnosis. Immuno-EM may be required to determine the role of the pathological immunoglobulin in the destruction of the peripheral nerve parenchyma. Diagnosis of such a direct involvement of peripheral nerve can endorse more aggressive treatment of real efficiency.

The frequencies of Killer immunoglobulin-like receptors and their HLA ligands in chronic inflammatory demyelinating polyradiculoneuropathy are similar to those in Guillian Barre syndrome but differ from those of controls, suggesting a role for NK cells in pathogenesis

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an acquired inflammatory neuropathy, which has similar clinical and pathological features to Guillain-Barré Syndrome (GBS), but differs in time course. We investigated the frequency of genes encoding Killer immunoglobulin-like receptors and their HLA ligands in subjects with CIDP, in subjects with GBS and in healthy controls. There were no differences in KIR gene frequency among the 3 groups. The gene frequencies for HLA-B Bw4-I were significantly greater in CIDP than HC, but did not differ from GBS. The frequency of the combination of 3DL1/HLA-B Bw4I was greater in CIDP than HC, but did not differ from that of GBS. These data raise the possibility of NK cell function being an important factor in the pathogenesis of CIDP.

An autopsy case involving a 12-year history of amyotrophic lateral sclerosis with CIDP-like polyneuropathy

Demyelinating polyneuropathy associated with amyotrophic lateral sclerosis (ALS) is quite rare. We herein present the case of a woman patient with a 12-year history of chronic inflammatory demyelinating polyneuropathy (CIDP)-like polyneuropathy who later developed bulbar palsy and respiratory failure. The autopsy findings revealed neuronal loss in the anterior horn and primary motor cortex with degeneration of the corticospinal tracts. Diffuse phosphorylated TAR DNA-binding protein of 43 kDa inclusions were observed in the anterior horn and cerebral cortices, including the temporal lobe. The final diagnosis was ALS with CIDP-like polyneuropathy. Compared with other reports of ALS with CIDP-like polyneuropathy, the present patient was younger and followed a relatively long clinical course, with no upper motor neuron signs.

[Pathogenesis of chronic inflammatory demyelinating polyneuropathy]

Chronic inflammatory demyelinating polyneuropathy (CIDP) is considered to be a demyelinating autoimmune disorder in the peripheral nervous system. Concerning cellular immune response, activity of IFN-gamma producing Th1 and IL-17 producing Th17 cells might be accelerated in patients with CIDP, while regulatory function of CD4+ CD25(high) Foxp3+ regulatory T cells might be diminished. Humoral immune responses against several myelin components such as myelin protein zero and gangliosides such as GM1 might be also induced in a part of patients with CIDP. Besides, growing body of evidences suggest that immune response against several molecules expressed in the noncompact myelin might be involved in the pathogenesis of CIDP.

Fas-mediated T-cell apoptosis is impaired in patients with chronic inflammatory demyelinating polyneuropathy

The Fas death receptor is expressed by activated lymphocytes and is involved in switching-off the immune response. Its inherited defects cause auto-immune lymphoproliferative syndrome. Impaired Fas function may also play a role in other auto-immune diseases, such as multiple sclerosis and type 1 diabetes mellitus. The aim of this work was to evaluate Fas function in T cells from patients with chronic inflammatory demyelinating polyneuropathy (CIDP). We evaluated Fas-induced apoptosis in T-cell lines from 27 patients with CIDP, 12 patients with acute inflammatory demyelinating polyneuropathy (AIDP), and 110 controls. CIDP patients displayed lower Fas function than both AIDP patients and controls, whereas no statistically significant difference was found between AIDP patients and controls. Moreover, Fas function was lower in CIDP patients with progressive course than in those with relapsing-remitting course and lower in CIDP patients with axonal damage than in those with pure demyelination. These data suggest that defective Fas function favours CIDP development and aggressive evolution.

[Biochemical features of chronic inflammatory demyelinating polyradiculoneuropathy]

Although there are no specific biological markers of chronic inflammatory demyelinating polyneuropathies (CIDP), biological investigations have played an important role in determining the limits of the concept of CIDP. This is best exemplified by the individualisation of demyelinating neuropathies associated with IgM monoclonal proteins reacting with glycolipids. The signification of CIDP associated with diabetes mellitus, monoclonal IgG or IgA, or mutations of myelin proteins has recently been discussed as they may have implications in our understanding of the pathophysiology of CIDP and raise the question of knowing whether they confer to CIDP a particular clinical presentation or evolution.

Increased circulating T cell reactivity to GM1 ganglioside in patients with Guillain–Barré syndrome

This study was performed to determine whether increased ganglioside-specific T cell reactivity can be detected in the peripheral blood of patients with Guillain-Barre syndrome (GBS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). T cell responsiveness to the gangliosides GM1, GM3, GD1a, GD1b, GD3, GT1b, GQ1b and sulphatide was assessed in peripheral blood mononuclear cells from untreated GBS patients (57), CIDP patients (43), patients with other peripheral neuropathies (55) and healthy control subjects (74) in a standard 6-day proliferation assay. Increased T cell reactivity to GM1 occurred in GBS patients compared to healthy controls and patients with other neuropathies. There was increased reactivity to GM3 in GBS patients compared to patients with other neuropathies but not compared to healthy controls. The frequencies of increased T cell reactivity to GM1 and GM3 in CIDP patients were intermediate between those of GBS patients and controls. We suggest that T cell reactivity to gangliosides might play a contributory role in the pathogenesis of GBS and perhaps CIDP.

Chronic inflammatory demyelinating polyneuropathy: decreased claudin-5 and relocated ZO-1

OBJECTIVES

To clarify the dynamics of molecules composing the blood-nerve barrier (BNB) in inflammatory neuropathies.

METHODS

The expression of four tight junction (TJ) proteins-claudin-1, claudin-5, occludin, and ZO-1-was analysed immunohistochemically in sural nerve biopsy specimens obtained from patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP).

RESULTS

Claudin-1 was detected only in perineurial cells, whereas claudin-5 was present in endothelial cells, irrespective of vessel location or size. Occludin and ZO-1 were found in perineurial cells, in addition to some epineurial and endoneurial endothelial cells. In CIDP, percentages of endoneurial small vessels immunoreactive for claudin-5 were significantly decreased, as were ZO-1 immunoreactive endoneurial small vessels, with staining localised to interfaces between cells. Claudin-1 and occludin immunoreactivity did not differ appreciably between the neuropathies examined.

CONCLUSIONS

The downregulation of claudin-5 and altered localisation of ZO-1 seen in CIDP specimens may indicate that BNB derangement occurs in inflammatory neuropathies. Further investigation of TJ molecules may suggest new treatments based on properties of the BNB.

Cyclo-oxygenases and prostaglandins in acute inflammatory demyelination of the peripheral nerve

OBJECTIVE

To investigate the expression of cyclo-oxygenases (COX), key enzymes in propagating inflammatory responses by converting arachidonic acid to prostaglandins, in inflammatory demyelinating disorders of the peripheral nervous system (PNS).

METHODS

Expression and distribution of COX messenger RNA (mRNA) and protein were studied in sural nerve biopsies, serum, and CSF samples from patients with Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), or, for comparison, with vasculitic neuropathy (VN), which is a inflammatory nondemyelinating disorder, and noninflammatory neuropathies (NIN) using RT-PCR, immunohistochemistry, and immunoblotting. To confirm functional COX-2 activity, the expression of prostaglandin E(2) (PGE(2)) and prostaglandin F(2alpha) (PGF(2alpha)) was evaluated by ELISA ex vivo and in vitro.

RESULTS

Whereas COX-1 expression was unaltered in all investigated groups, a significant upregulation of COX-2 mRNA was detected in sural nerves from patients with GBS, CIDP, or VN but not in control subjects with noninflammatory disorders. Macrophages were identified as its primary cellular source. Increased COX-2 protein levels were detectable in serum and CSF from all patients with GBS and, in smaller numbers only, in samples from patients with CIDP or VN but not from the NIN group studied. Moreover, increased levels of PGE(2) and PGF(2alpha) were measurable in sera from patients with GBS, CIDP, or VN and in cell culture supernatants from in vitro stimulated macrophages, indicative of COX-2 activity.

CONCLUSIONS

Cyclo-oxygenase-2, expressed by macrophages, may generate prostaglandins during acute inflammatory demyelination of the peripheral nerve.

T-cell cytotoxicity of human Schwann cells: TNFalpha promotes fasL-mediated apoptosis and IFN gamma perforin-mediated lysis

The ability of resident cells to induce apoptosis of invading immune cells is a major regulatory factor operating in immune-privileged tissues, including the nervous system. We investigated the cellular and molecular factors participating in modulation of immune response in peripheral nerves, focusing on two cytotoxic pathways: fas ligand (fasL) and perforin. fasL and perforin expression was found by immunochemistry on Schwann cells (Sc) in nerve biopsies from patients with chronic inflammatory demyelinating polyneuritis and on human Sc cultures. Treatment of Sc with tumor necrosis factor (TNF) alpha and interferon (IFN) gamma upregulated the expression of both molecules. In a coculture model, Sc exposed to TNFalpha or IFN gamma were able to induce both apoptotic and lytic injury of T-lymphocytes. Inactivation of fasL with the neutralizing antibody NOK-2 abolished T-cell apoptosis induced by Sc treated with TNFalpha, but not by Sc treated with IFN gamma. Conversely, T-cell lysis was significantly decreased when IFN gamma-activated Sc were treated with concanamycin A, which inhibited perforin release. At variance with T-lymphocytes, B-cells were less sensitive to cytokine-treated Sc toxicity. Thus, Sc exposed to inflammatory cytokines have the capacity of inducing selective damage of T-lymphocytes and have the potential of regulating the immune response in the peripheral nervous system.

Cytokines in sural nerve biopsies from inflammatory and non-inflammatory neuropathies

Proinflammatory cytokines are supposed to play a major role in the pathophysiology of vasculitis and in the development of neuropathic pain. Here we studied the cytokine expression in sural nerve biopsy specimens from patients with vasculitic and other inflammatory and non-inflammatory neuropathies, and investigated whether an increased cytokine expression was correlated with the presence of neuropathic pain. We used immunohistochemistry including double labeling and morphometry to localize and quantify the expression of interleukin-1 beta (IL-1beta), IL-6, and tumor necrosis factor-alpha (TNF) in sural nerve biopsy samples of 41 patients with vasculitic neuropathy (VANP), chronic inflammatory demyelinating neuropathy (CIDP), non-inflammatory chronic axonal neuropathy (CANP), and 3 controls. Overall cytokine immunoreactivity was highest in VANP, less strong in CIDP and lowest in CANP. Cytokine immunoreactivity was directly correlated with the degree of axonal degeneration, endoneurial macrophages and epineurial T cells. In VANP and CANP, a higher cytokine content was associated with neuropathic pain.

Peripheral nerve extracellular matrix remodeling in Charcot-Marie-Tooth type I disease

Charcot-Marie-Tooth type 1 disease (CMT1) is a group of inherited demyelinating neuropathies caused by mutations in genes expressed by myelinating Schwann cells. Rather than demyelination per se, alterations of Schwann cell-axon interactions have been suggested as the main cause of motor-sensory impairment in CMT1 patients. In an attempt to identify molecules that may be involved in such altered interactions, the extracellular matrix (ECM) remodeling occurring in CMT1 sural nerves was studied. For comparison, both normal sural nerves and sural nerves affected by neuropathies of different origin were used. The study was performed by immunohistochemical analysis using antibodies against collagen types I, III, IV, V, and VI and the glycoproteins fibronectin, laminin, vitronectin and tenascin. Up-regulation of collagens, fibronectin and laminin was commonly found in nerve biopsy specimens from patients affected by CMT1 and control diseases, but higher levels of overexpression were usually observed in CMT1 cases. On the other hand, vitronectin and tenascin appeared preferentially induced in CMT1 compared to other pathologies investigated here. Vitronectin, whose expression in normal nerves was limited to perineurial layers and to the walls of epineurial and endoneurial vessels, became strongly and diffusely expressed in the endoneurium in most CMT1 biopsy specimens. The expression of tenascin, confined to the perineurium, to vessel walls and to the nodes of Ranvier in normal nerves, was displaced and extended along the internodes of several nerve fibers in the majority of CMT1 nerves. Thus, compared with our pathological controls CMT1 seemed to determine the most extensive remodeling of peripheral nerve ECM.

N(epsilon)-Carboxymethyllysine in diabetic and non-diabetic polyneuropathies

Increased oxidative stress and advanced glycosylation are important factors in the development of diabetic neuropathy. In non-diabetic neuropathies their influence has not been investigated in detail so far. We studied the localisation of N(epsilon)-carboxymethyllysine (CML) - a biomarker for oxidative stress - by immunohistochemistry in sural nerve biopsies of 31 patients with different polyneuropathies [diabetic polyneuropathy (n=5), alcohol-associated polyneuropathy (n=4), vitamin B12-deficient polyneuropathy (n=6), chronic inflammatory demyelinating polyneuropathy (CIDP) (n=6), vasculitic neuropathy (n=6), Charcot-Marie-Tooth disease type I (CMT I) (n=4)] and 4 normal controls. CML was detected in the perineurium of patients with diabetic, alcohol-associated, vitamin B12-deficient and vasculitic polyneuropathies. Epineurial, perineurial and endoneurial vessels were CML positive in diabetic, vitamin B12-deficient and vasculitic polyneuropathies. CML was also found in mononuclear inflammatory cells in vasculitic neuropathy. In CIDP and normal controls there was only marginal perineurial CML deposition in 2/6 and 1/4 cases. In CMT I no CML was detected. Immunohistochemical results were confirmed by immunoblot. Our data suggest a role of oxidative stress in the pathogenesis not only of diabetic but also of alcohol-associated, vitamin B12-deficient and vasculitic polyneuropathies. It may be a minor pathogenetic factor in CIDP and may not be involved in CMT I. Underlying causes for increased oxidative stress may be an elevated production of reactive oxygen species and an impairment of antioxidative defences. Therefore, an antioxidative treatment should be considered in alcohol-associated, vitamin B12-deficient and vasculitic polyneuropathy.

Parallel expression of neurotrophic factors and their receptors in chronic inflammatory demyelinating polyneuropathy

The mRNA levels of nerve growth factor (NGF), glial cell line-derived neurotrophic factor (GDNF), ciliary neurotrophic factor (CNTF), leukemia inhibitory factor (LIF), and interleukin-6 (IL-6) were examined in sural nerves of 22 patients with chronic inflammatory demyelinating polyneuropathy (CIDP). The mRNAs for NGF, GDNF, LIF, and IL-6 were upregulated, whereas CNTF mRNA was downregulated significantly in the nerves. The NGF, GDNF, and CNTF, but not LIF mRNA expressions were parallel to those of the cognate receptors, suggesting that these cognate soluble receptors effectively present these factors to maintain and regenerate the axons. Furthermore, IL-6 mRNA expression was significantly parallel to both binding and signal-transducing receptor expression, implying a role of the IL-6 signal for non-neuronal cells in CIDP. These findings indicate that multiple neurotrophic growth factors and cytokines are expressed cooperatively with their concomitant receptors in the nerve lesions of CIDP and play an important role particularly in nerve repair.

Expression and distribution of transcription factor NF-kappaB and inhibitor IkappaB in the inflamed peripheral nervous system

The NF-kappaB family of transcription factors is critically involved in the immune response. The activity of these proteins is under strict control of an inhibitory molecule called IkappaB. The present study investigated the expression and distribution pattern of NF-kappaB and IkappaB in sural nerve biopsies obtained from patients with Guillain-Barré syndrome, chronic inflammatory demyelinating polyradiculoneuropathy, and various non-inflammatory neuropathies. In inflammatory demyelinating as well as non-inflammatory neuropathies, NF-kappaB was primarily expressed by macrophages, as determined by immunohistochemistry. IkappaB, however, could be localized to macrophages as well as T cells in inflammatory demyelinating neuropathies, whereas in non-inflammatory controls Schwann cells were found to be the primary cell type expressing this inhibitor. Quantitation of immunoreactivity revealed a statistically significant increase of NF-kappaB expression in inflammatory demyelinating cases compared to controls. Our results suggest an important function of the NF-kappaB pool in the genesis of inflammatory demyelination in the peripheral nervous system.

Expression of the co-stimulatory molecule BB-1, the ligands CTLA-4 and CD28 and their mRNAs in chronic inflammatory demyelinating polyneuropathy

To examine whether the Schwann cells in patients with autoimmune neuropathies have the potential to behave as professional antigen-presenting cells, we investigated the expression of the co-stimulatory molecules BB-1, B7-1 (CD80) B7-2 (CD86) and their counter-receptors CD28 or CTLA-4 (CD152) at the protein and mRNA levels in sural nerve biopsies of patients with chronic inflammatory demyelinating polyneuropathy (CIDP), CIDP associated with human immunodeficiency virus infection (HIV-CIDP), IgM paraproteinaemic neuropathy and normal or non-immune axonal neuropathy. In single- and double-labelling experiments, we used the S-100 antigen as a pan-Schwann cell marker, myelin-associated glycoprotein as a marker for myelinating Schwann cells and the fibrillary acidic protein as a marker for unmyelinating Schwann cells. The expression of the B7 family of molecules was limited to BB-1 and was observed only on the Schwann cells. There was constitutive expression of BB-1 on unmyelinating Schwann cells in all nerves studied. However, in CIDP and HIV-CIDP, but not the other diseases, there was prominent upregulation of BB-1 on the myelinating Schwann cells. The endoneurial T cells in the proximity of BB-1-positive Schwann cells expressed the CD28 or CTLA-4 counter-receptors. Reverse transcription-polymerase chain reaction confirmed that these ligands were upregulated only in CIDP. Because the myelinating BB-1-positive Schwann cells expressed HLA-DR antigen, the findings indicate that, in CIDP, Schwann cells possess the necessary markers to function as antigen-presenting cells.

The spectrum of chronic inflammatory demyelinating polyneuropathy

Research criteria for the diagnosis of chronic inflammatory demyelinating polyneuropathy (CIDP) were proposed by an Ad Hoc Subcommittee of the American Academy of Neurology (AAN) in 1991, and since then these criteria have been widely used in clinical studies. We have been impressed by the frequent finding of electrophysiological changes of a demyelinating neuropathy in patients whose clinical presentation does not conform to the usually accepted clinical phenotype of CIDP. To determine the clinical spectrum of CIDP, we conducted a retrospective review of patients of the peripheral electrophysiology laboratory of the University of Miami-Jackson Memorial Medical Center. Diagnostic criteria for acquired demyelination of an individual nerve were adapted from the AAN research criteria for the diagnosis of CIDP (1991). Patients were accepted for inclusion when such evidence was demonstrated in at least one motor nerve or at least two sensory nerves. We then reviewed the clinical phenotype and the underlying etiology of the neuropathy in these cases. Eighty-seven patients, 63 male and 24 female, age of onset 4-84 (mean 49.3) years, met these inclusion criteria. Forty-seven patients (54%) had distinct features outside the usual clinical presentation of CIDP. Of these, 15 (17%) had predominantly distal features, 13 (15%) had exclusively sensory polyneuropathy; seven (8%) had markedly asymmetric disease, seven (8%) had associated CNS demyelination, four (5%) had predominant cranial nerve involvement, and one (1%) had only the restless legs syndrome. An associated medical condition that may have been responsible for the acquired demyelinating neuropathy was present in 60% of the patients. We conclude that spectrum of CIDP is broader than would be indicated by the strict application of the AAN research criteria, and that many of the cases meeting more liberal criteria frequently respond to immunosuppressive therapy.