T-cell-mediated epineurial vasculitis and humoral-mediated microangiopathy in cryoglobulinemic neuropathy

Peripheral Neuropathy in Patients with Hepatitis C Infection-Reversibility after HCV Eradication: A Single Center Study

Chronic hepatitis C virus (HCV) infection is characterized by a variety of extra-hepatic manifestations; peripheral neuropathy (PN) is one of the most common, especially when mixed cryoglobulinemia (MCG) is present. The prevalence and risk factors of HCV-related PN in the absence of MCG are largely unknown. We conducted a prospective, single-center study, examining the prevalence and reversibility of HCV-associated neuropathy in the absence of MCG. Nerve fiber density in the epidermis was evaluated through skin biopsy and electroneurography (ENG) before HCV-treatment initiation and 1 year post sustained virological remission (SVR). Forty HCV-infected individuals (nine HIV co-infected) with no other neuron-harming factors were included; four other HCV mono- and three HIV co-infected individuals were excluded due to presence of diabetes, B12 insufficiency, or neurotoxic drugs. Twelve consecutive controls with no neuron-harming conditions were also recruited; eight more were excluded due to meeting exclusion criteria. Four patients had ENG signs of polyneuropathy (two with HCV mono- and two with HIV co-infection), while seven more (five with HCV mono- and two with HIV co-infection) had signs of mono-neuropathy, leading to PN prevalences of 22.5% and 44% for mono- and co-infection, respectively (p value 0.179). The two patients with HCV mono-infection and polyneuropathy and the one with ulnar nerve damage showed ENG improvement 1 year post SVR. Regarding intraepidermal nerve density, HCV infection, irrespective of HIV co-infection, was correlated with a lower intraepidermal neuron density that improved 1 year post SVR (p value 0.0002 for HCV and 0.0326 for HCV/HIV co-infected patients). PN is common in HCV infection; successful eradication of HCV leads to PN improvement.

Quantitative motor unit potential analysis and nerve conduction studies for detection of subclinical peripheral nerve dysfunction in patients with compensated liver cirrhosis

Background

Peripheral neuropathy is an underestimated problem of compensated liver cirrhosis despite its negative effect on quality of life. The aim was to assess the role of meticulous electrophysiological screening (nerve conduction responses and quantitative motor unit potential analysis) of subclinical peripheral nerve dysfunction in patients with compensated cirrhosis and also to explore its relations with different characteristics of liver disease. Severity of cirrhosis was assessed by Child–Pugh and albumin-bilirubin (ALBI) scores.

Results

Prevalence of hepatic neuropathy (HN) was 82%. It involved sensory and motor fibers (66%), and its pathophysiology was axonal (53.7%) or mixed axonal and demyelinating (46.3). The most sensitive discriminating tests were ulnar sensory conduction velocity (area under curve (AUC) = 0.915) and peak latency (AUC = 0.887), peroneal motor conduction velocity (AUC = 0.885), ulnar distal motor latency (AUC = 0.842), and first dorsal interosseous number of phases (AUC = 0.736). HN showed significant correlation with the severity of liver disease assessed by both child (P = 0.029) and ALBI (P = 0.016) scores and also correlated with the low serum albumin level (P = 0.001).

Conclusions

Subclinical mild axonal polyneuropathy is very common in post-hepatitis C compensated cirrhosis picked up by meticulous electrophysiological testing, and it is related to severity of liver cirrhosis and low serum albumin level.

Peripheral neuropathy after viral eradication with direct-acting antivirals in chronic HCV hepatitis: A prospective study

BACKGROUND

HCV-related extra-hepatic complications include peripheral neuropathies, with important prevalence and impact. A recent metanalysis of previous intervention trials concluded for insufficient data to support evidence-based treatments for this complication. In this longitudinal study, we assessed for the first time prevalence and outcome of neuropathy in a cohort of patients with chronic HCV, before and after direct-acting antiviral agent (DAA) treatment.

METHOD

Ninety-four patients (mean age 58.5 ± 9.9, infection duration 22.2 ± 6.3 years) without systemic and metabolic diseases, underwent neurological examination and electroneurography studies before (T0) and 10.4 ± 1.7 months after the end of DAA therapy (T1), and cryoglobulins (CG) assessment. Muscle strength was evaluated by Medical Research Council (MRC) score; neuropathic pain, sensory function, disability, quality of life were assessed by validated questionnaires (DN4, NPSI, SSS, INCAT and Euro-QoL).

RESULTS

At T0, sensory-motor neuropathy was detected in 22 patients (23%), reflexes were depressed in 32 (34%) with no association with infection duration, viral load, age, CG. Neuropathic pain (DN4 ≥4) was present in 37 patients (39%). At T1, out of the 22 patients with altered electroneurography, 3 had died or developed HCC, 4 showed normal electroneurography, and nerve amplitude parameters tended to improve in the whole group. Only 11 patients (12%) had depressed reflexes and 10 (11%) DN4 ≥4 (P < .05 compared to T0). Scores for MRC, questionnaires and Euro-QoL improved significantly (P < .05).

CONCLUSION

Our study confirms the high prevalence of clinical and subclinical peripheral sensory-motor neuropathy in patients with HCV infection and indicates improvement after eradication by DAA. These results support the need for larger intervention studies.

Hcv and Autoimmunity in Rheumatic Diseases

HCV is a global health problem affecting mainly the liver and often characterized by extrahepatic manifestions mediated by autoimmune reactions. Among these, arthritis and arthralgia are most frequent, as well as the presence of cryoglobulinemia that may induce vasculitis, and sicca syndrome. Thus, HCV appears to be a trigger for autoimmune response as demonstrated by the finding of autoantibody in a high percentage of serum of these patients. Therefore, it is important that clinicians recognize these autoimmune manifestations as symptoms due to an autoimmune activity triggered by HCV, in order to give the correct diagnosis and start an effective therapy strategy. Therefore, clinical examination, searching of markers of infection as well as autoantibody patterns should be performed to make a correct differential diagnosis. The treatment should be based on antiviral drugs associated to immunosuppressive drugs according to autoimmune manifestations.

Neurologic manifestations associated with cryoglobulinemia: A single center experience

INTRODUCTION

Limited information is available describing the spectrum of neurological complications of cryoglobulinemia.

METHODS

Single center retrospective review of patients with neurologic symptoms and elevated serum cryoglobulins, with their potential association being classified as definite, possible, or unlikely using defined criteria.

RESULTS

Among 492 patients, 131 (87 classified as definite and 44 as possible) had neurologic symptoms associated with cryoglobulinemia. Common comorbidities included hepatitis C (N = 43), monoclonal gammopathy of undetermined significance (N = 20), Sjogren's syndrome (N = 17), membranoproliferative glomerulonephritis (N = 17), and systemic lupus erythematosus (N = 10). Features supporting an association between cryoglobulinemia and neurological symptoms were the presence of purpura (p < .001), positive rheumatoid factor (p = .001) and low C4 (p = .002). Common peripheral neurological diagnoses were symmetric polyneuropathy (N = 84), small fiber neuropathy (N = 25), and mononeuritis multiplex (N = 16). Central neurological manifestations were infrequent and included seizures (N = 3), posterior reversible encephalopathy syndrome (N = 2), intracerebral hemorrhage (N = 1), vasculitis (N = 1), rapidly progressive dementia (N = 1), lymphoma (N = 1), and myelitis/meningitis (N = 1). Treatments utilized included corticosteroids (N = 74), rituximab (N = 42), cyclophosphamide (N = 27), methotrexate, azathioprine, or mycophenolate mofetil (N = 28), anti-viral therapy (N = 20), plasmapheresis (N = 16), and intravenous immunoglobulin (N = 20). Neurologic symptoms associated with cryoglobulinemia remained stable or improved in 86% of patients.

CONCLUSION

This study describes a wide spectrum of patients with neurologic symptoms attributed to cryoglobulinemia and provides a framework to approach this challenging diagnosis.

Clinical electrophysiology of axonal polyneuropathies

Axonal neuropathies encompass a wide range of acquired and inherited disorders with electrophysiologic characteristics that arise from the unique neurophysiology of the axon. Accurate interpretation of nerve conduction studies and electromyography requires an in-depth understanding of the pathophysiology of the axon. Here we review the unique neurophysiologic properties of the axon and how they relate to clinical electrodiagnostic features. We review the length-dependent Wallerian or "dying-back" processes as well as the emerging body of literature from acquired axonal neuropathies that highlights the importance of axonal disease at the nodes of Ranvier. Neurophysiologic features of individual inherited and acquired axonal diseases, including primary nerve disease as well as systemic immune mediated, metabolic, and toxic diseases involving the peripheral nerve, are reviewed. This comprehensive review of electrodiagnostic findings coupled with the current understanding of pathophysiology will aid the clinician in the evaluation of axonal polyneuropathies.

Autoimmune Neuromuscular Diseases Induced by Immunomodulating Drugs

Immunomodulating drugs are widely used in autoimmune, transplant, and cancer patients. However, these drugs are associated with various autoimmune neuromuscular diseases such as demyelinating polyneuropathy, myasthenia gravis, and myositis. Early recognition of these complications and immediately terminating these drugs are very essential since some are life-threatening conditions. This review provides a general overview of drug-induced autoimmunity and autoimmune neuromuscular diseases associated with tumor necrosis factor alpha (TNF-α) antagonists, immune checkpoint inhibitors, and interferon (IFN) type 1 (IFN-β and IFN-α).

Screening for Electrophysiological Abnormalities in Chronic Hepatitis C Infection: Peripheral Neuropathy and Optic Neuropathy

INTRODUCTION

To investigate the existence of peripheral and optic neuropathies in asymptomatic individuals with hepatitis C infection.

METHODS

Thirty consecutive patients who were followed in a hepatitis C outpatient clinic were recruited for electrophysiological evaluation together with 30 age- and gender-compatible healthy controls. All patients had a detailed neurological examination. The information regarding the disease duration and management with interferons were collected. Nerve conduction studies and visual evoked potentials (VEP) were recorded in all subjects. The results of the patient and control groups were statistically compared.

RESULTS

Of the patients with hepatitis C infection, 16 were females and 14 males. The mean age was 57.5 years, and the average disease duration was 6.43 years. The P100 latencies in the patient group were within normal limits, while the amplitudes were meaningfully small by comparison with the controls. There were some abnormalities in the nerve conduction studies of 15 patients. Sensorial neuropathy was detected in two patients, sensorimotor polyneuropathy in four, carpal tunnel syndrome in seven, and carpal tunnel syndrome and sensorimotor polyneuropathy as comorbid states in another two patients. The nerve conduction studies and VEP parameters were entirely normal in the control group.

CONCLUSION

Hepatitis C-related neurological abnormalities may occur both in the central and peripheral nervous system. Mononeuritis multiplex, sensorial axonal neuropathy, and multiple mononeuropathies are some of the presentations of the peripheral nervous system involvement. The mode of infection is considered to be via vasculitic mechanisms. In addition, optic neuropathy is a known complication of interferon treatment. Autoantibodies, cytokines, chemokines, and cryoglobulins are accused to play roles in the pathogenesis. In this study, we investigated the involvement of the peripheral nervous system and optic nerves in a group of patients with hepatitis C. The results were in favor of peripheral nerve injury of various types and optic neuropathy of the axonal type.

Mechanisms of distal axonal degeneration in peripheral neuropathies

Peripheral neuropathy is a common complication of a variety of diseases and treatments, including diabetes, cancer chemotherapy, and infectious causes (HIV, hepatitis C, and Campylobacter jejuni). Despite the fundamental difference between these insults, peripheral neuropathy develops as a combination of just six primary mechanisms: altered metabolism, covalent modification, altered organelle function and reactive oxygen species formation, altered intracellular and inflammatory signaling, slowed axonal transport, and altered ion channel dynamics and expression. All of these pathways converge to lead to axon dysfunction and symptoms of neuropathy. The detailed mechanisms of axon degeneration itself have begun to be elucidated with studies of animal models with altered degeneration kinetics, including the slowed Wallerian degeneration (Wld(S)) and Sarm knockout animal models. These studies have shown axonal degeneration to occur through a programmed pathway of injury signaling and cytoskeletal degradation. Insights into the common disease insults that converge on the axonal degeneration pathway promise to facilitate the development of therapeutics that may be effective against other mechanisms of neurodegeneration.

Treatment for cryoglobulinemic and non-cryoglobulinemic peripheral neuropathy associated with hepatitis C virus infection

BACKGROUND

Peripheral neuropathy is the most common neurologic complication of hepatitis C virus (HCV) infection. The pathophysiology of the neuropathy associated with HCV is not definitively known; however, proposed mechanisms include cryoglobulin deposition in the vasa nervorum and HCV-mediated vasculitis. The optimal treatment for HCV-related peripheral neuropathy has not been established.

OBJECTIVES

To assess the effects of interventions (including interferon alfa, interferon alfa plus ribavirin, corticosteroids, cyclophosphamide, plasma exchange, and rituximab) for cryoglobulinemic or non-cryoglobulinemic peripheral neuropathy associated with HCV infection.

SEARCH METHODS

On 26 August 2014, we searched the Cochrane Neuromuscular Disease Group Specialized Register, CENTRAL, MEDLINE, and EMBASE. We also searched two trials registers, the Networked Digital Library of Theses and Dissertations (NDLTD) (October 2014), and three other databases. We checked references in identified trials and requested information from trial authors to identify any additional published or unpublished data.

SELECTION CRITERIA

We included all randomized controlled trials (RCTs) and quasi-RCTs involving participants with cryoglobulinemic or non-cryoglobulinemic peripheral neuropathy associated with HCV infection. We considered any intervention (including interferon alfa, interferon alfa plus ribavirin, corticosteroids, cyclophosphamide, plasma exchange, and rituximab) alone or in combination versus placebo or another intervention ('head-to-head' comparison study design) evaluated after a minimum interval to follow-up of at least six months.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by The Cochrane Collaboration. The planned primary outcome was change in sensory impairment (using any validated sensory neuropathy scale or quantitative sensory testing) at the end of the follow-up period.  Other planned outcomes were: change in impairment (any validated combined sensory and motor neuropathy scale), change in disability (any validated disability scale), electrodiagnostic measures, number of participants with improved symptoms of neuropathy (global impression of change), and severe adverse events.

MAIN RESULTS

Four trials of HCV-related cryoglobulinemia fulfiled selection criteria and the review authors included three in quantitative synthesis. All studies were at high risk of bias. No trial addressed the primary outcome of change in sensory impairment. No trial addressed secondary outcomes of change in combined sensory and motor impairment, disability, or electrodiagnostic measures. A single trial of HCV-related mixed cryoglobulinemia treated with pegylated interferon alfa (peginterferon alfa), ribavirin, and rituximab versus peginterferon alfa and ribavirin did not show a significant difference in the number of participants with improvement in neuropathy at 36 months post treatment (risk ratio (RR) 4.00, 95% confidence interval (CI) 0.27 to 59.31, n = 9). One study of interferon alfa (n = 22) and two studies of rituximab (n = 61) provided adverse event data. Severe adverse events were no more common with interferon alfa (RR 7.00, 95% CI 0.38 to 128.02) or rituximab (RR 3.00, 95% CI 0.13 to 67.06) compared to the control group.

AUTHORS' CONCLUSIONS

There is a lack of RCTs and quasi-RCTs addressing the effects of interventions for peripheral neuropathy associated with HCV infection. At present, there is insufficient evidence from RCTs and quasi-RCTs to make evidence-based decisions about treatment.

Renal involvement in HCV-related vasculitis

Renal involvement has been frequently reported in the setting of hepatitis C virus (HCV) infection. The most common renal pathology associated with chronic HCV infection is type I membranoproliferative glomerulonephritis associated with type II mixed cryoglobulinemia, while membranoproliferative glomerulonephritis without cryoglobulinemia and membranous nephropathy were less frequently reported. Rarely, focal segmental glomerulosclerosis, fibrillary and immunotactoid glomerulopathies, and thrombotic microangiopathies were described during the course of HCV infection. In the present review, we have focused on renal involvement in HCV-related vasculitis.

The vasculitic neuropathies: an update

PURPOSE OF REVIEW

Vasculitic neuropathy is a heterogeneous disorder that usually occurs in systemic diseases, but less commonly appears as nonsystemic vasculitic neuropathy (NSVN). This review is intended to highlight recent developments in the field of vasculitic neuropathies.

RECENT FINDINGS

A Peripheral Nerve Society guideline provides data-driven consensus recommendation on classification of vasculitic neuropathies and diagnosis/treatment of NSVN. NSVN is sometimes accompanied by subclinical inflammation of adjacent skin. Amyotrophic lateral sclerosis with sensory involvement can mimic NSVN. Systemic vasculitides with neuropathy include polyarteritis nodosa, microscopic polyangiitis (MPA), rheumatoid vasculitis, Churg-Strauss syndrome (CSS), and hepatitis C-related mixed cryoglobulinemic vasculitis (MCV). At autopsy, MPA affects limb nerves diffusely, with maximal damage in proximal/middle segments. CSS can be accompanied by antineutrophil cytoplasmic antibodies (ANCAs), but most patients with neuropathy lack ANCAs. Cryoglobulinemic neuropathies are usually caused by vasculitis, irrespective of phenotype. Two randomized trials revealed rituximab to be noninferior to cyclophosphamide for inducing remission in ANCA-associated vasculitis. Many reports also document efficacy of rituximab in MCV.

SUMMARY

Consensus guidelines on NSVN should be evaluated prospectively. MPA-associated vasculitic neuropathy results from vasculitic lesions distributed diffusely throughout peripheral extremity nerves. Rituximab is effective for ANCA-associated and cryoglobulinemic vasculitis with neuropathy.

Vasculitic neuropathy

Vasculitis is a primary phenomenon in autoimmune diseases such as polyarteritis nodosa, Wegener's granulomatosis, Churg-Strauss syndrome, microscopic polyangiitis, and essential mixed cryoglobulinemia. As a secondary feature vasculitis may complicate, for example, connective tissue diseases, infections, malignancies, and diabetes. Vasculitic neuropathy is a consequence of destruction of the vessel wall and occlusion of the vessel lumen of small epineurial arteries. Sometimes patients present with nonsystemic vasculitic neuropathy, i.e., vasculitis limited to peripheral nerves and muscles with no evidence of further systemic involvement. Treatment with corticosteroids, sometimes in combination with other immunosuppressants, is required to control the inflammatory process and prevent further ischemic nerve damage.

Neuromuscular diseases associated with chronic hepatitis C virus infection

Hepatitis C virus (HCV) infection is a growing international health problem, and more than 170 million people are chronic carriers. Up to 50% of HCV-positive patients develop at least one extrahepatic manifestation during the course of disease. To varying degrees of certainty, there is evidence of an association between chronic HCV infection and a variety of neuromuscular diseases. The pathogenesis of most extrahepatic diseases remains unclear but possibly includes HCV lymphotropism and/or HCV-induced autoantibodies. The therapeutic approach to HCV-associated autoimmune disorders entails eradication of HCV with one of the recombinant interferon-alpha preparations with or without additional immunosuppressive drugs.

HCV-related nervous system disorders

Chronic infection with hepatitis C virus (HCV) is associated with a wide spectrum of extrahepatic manifestations, affecting different organ systems. Neurological complications occur in a large number of patients and range from peripheral neuropathy to cognitive impairment. Pathogenetic mechanisms responsible for nervous system dysfunction are mainly related to the upregulation of the host immune response with production of autoantibodies, immune complexes, and cryoglobulins. Alternative mechanisms include possible extrahepatic replication of HCV in neural tissues and the effects of circulating inflammatory cytokines and chemokines.

Systemic vasculitis in patients with hepatitis C virus infection with and without detectable mixed cryoglobulinemia

OBJECTIVE

to describe hepatitis C virus (HCV)-related systemic vasculitis in patients without detectable mixed cryoglobulinemia (MC) and to compare them to typical cases of HCV-MC vasculitis.

METHODS

twelve HCV RNA+ patients with histologically proven vasculitis in the absence of detectable MC (cases) were retrospectively compared with 48 HCV RNA+ patients with MC vasculitis (controls). Each case was matched with 4 controls for age and sex.

RESULTS

the main epidemiological and virologic features were similar between cases and controls. No clinical difference was found, except for lower rates of arthralgias (33% vs 71%; p = 0.02) and purpura (50% vs 83%; p = 0.03) in cases. Cases showed higher mean serum C3 (1.17 ± 0.21 vs 0.93 ± 0.23 g/l; p = 0.01) and median C4 levels (0.25 vs 0.04 g/l; p < 0.001), lower median serum IgM levels (0.6 vs 1.9 g/l; p < 0.001), and lower rates of rheumatoid factor positivity (8% vs 82%; p < 0.001) than controls. The main histologic features were similar between cases and controls. Immunofluorescence analysis of skin biopsy from 1 case revealed perivascular deposits of C3 and IgA. After treatment, overall clinical response of vasculitis (75% vs 83%) and sustained virological response (40% vs 64%; p = 0.3) were similar between cases and controls, except for higher complete clinical response (42% vs 73%; p = 0.05) in controls.

CONCLUSION

HCV-related systemic vasculitis may occur in the absence of detectable MC. Our findings suggest that such vasculitis probably results from immune complex-mediated mechanisms, and that the therapeutic management of such vasculitis should be similar to that of HCV-MC vasculitis.

Restoration of peripheral immune homeostasis after rituximab in mixed cryoglobulinemia vasculitis

Rituximab, an anti-CD20 monoclonal antibody, has been used to treat autoimmune disorders such as mixed cryoglobulinemia (MC). However, its mechanisms of action as well as the effects on cellular immunity remain poorly defined. We investigated the changes of peripheral blood B- and T-cell subsets, the clonal VH1-69 cells, as well as the cytokine profile following rituximab therapy. The study involved 21 patients with hepatitis C-related MC who received rituximab, of whom 14 achieved a complete response. Compared with healthy and hepatitis C virus (HCV) controls, pretreatment abnormalities in MC patients included a decreased percentage of naive B cells (P < .05) and CD4(+)CD25(+)FoxP3(+) regulatory T cells (P = .02) with an increase in memory B cells (P = .03) and plasmablasts (P < .05). These abnormalities were reverted at 12 months after rituximab. Clonal VH1-69(+) B cells dramatically decreased following treatment (32% +/- 6% versus 8% +/- 2%, P = .01). Complete responders of rituximab exhibited an expansion of regulatory T cells (P < .01) accompanied with a decrease in CD8(+) T-cell activation (P < .01) and decreased production of interleukin 12 (IL-12; P = .02) and interferon-gamma (IFN-gamma; P = .01). Our findings indicate that in patients with MC, response to B-cell depletion induced by rituximab effectively normalizes many of the disturbances in peripheral B- and T-lymphocyte homeostasis.

Cryoglobulinemia

Cryoglobulinemia refers to the presence in serum of immunoglobulins that precipitate at a cold temperature. Type I cryoglobulins are single monoclonal immunoglobulins usually associated with haematological disorders. Types II and III are mixed cryoglobulins, composed of monoclonal or polyclonal IgM respectively, having rheumatoid factor activity that bind to polyclonal immunoglobulins. Mixed cryoglobulinemia (MC) syndrome is a consequence of immune-complex mediated vasculitis and is characterized by a typical clinical triad: purpura, weakness, arthralgias; many organs particularly kidney and peripheral nervous system may be involved. MC may be associated with infectious and systemic disorders and since 1990 studies have demonstrated that hepatitis C virus (HCV) may be considered the principal trigger of the disease. The relation between MC and HCV infection shows new insights in the interpretation of the link between viral infection, autoimmune phenomena and lymphoproliferative disorders evolution. In fact, the virus chronically stimulates B-cell polyclonal proliferation from which a monoclonal population may emerge. In symptomatic patients with HCV related MC therapeutic strategy should include an attempt at viral eradication. Antiviral therapy may also be effective in determining the regression of B-cell lymphoproliferative disorder. Rituximab could represent a safe and effective alternative to standard immunosuppression and exerts selective B-cell control.

Role of matrix metalloproteinases, proinflammatory cytokines, and oxidative stress-derived molecules in hepatitis C virus-associated mixed cryoglobulinemia vasculitis neuropathy

OBJECTIVE

Mixed cryoglobulinemia (MC) is a systemic vasculitis, usually associated with hepatitis C virus (HCV) infection. The molecular mechanisms responsible for HCV-associated MC (HCV-MC) vasculitis are largely unknown. This study was undertaken to assess the expression profile of selected genes involved in inflammatory vascular damage in patients with HCV-MC vasculitis, patients with polyarteritis nodosa (PAN), and patients with noninflammatory idiopathic neuropathy.

METHODS

The quantitative expression levels of 42 selected genes involved in inflammatory vascular damage were assessed in nerve lesions of patients with HCV-MC vasculitis, PAN (rheumatic disease controls), and noninflammatory idiopathic neuropathy (noninflammatory neuropathy controls), using real-time reverse transcriptase-polymerase chain reaction. Genes were considered to be differentially expressed when there was a >2-fold difference in mean expression levels between groups and the P value was less than 0.05.

RESULTS

Expression levels of 8 genes were significantly increased in HCV-MC patients versus control patients with noninflammatory idiopathic neuropathy, with the highest increase for metallothionein 1 H (MT1H), a hypoxic and oxidative stress protein. Compared with PAN patients, HCV-MC patients had higher expression levels of genes encoding oxidative stress-derived molecules (MT1H, endothelial cell nitric oxide synthase 3, Hsp70, and Hsp90) and tissue plasminogen activator and lower expression levels of matrix metalloproteinase 7 (MMP-7). HCV-MC neuropathies were classified according to their morphologic pattern and the presence or absence of necrotizing arteritis. MMP-1, MMP-7, MMP-9, and interleukin-1beta were up-regulated in patients with necrotizing arteritis.

CONCLUSION

This comprehensive molecular study of HCV-MC vasculitis provides strong evidence that MMPs, proinflammatory cytokines, and oxidative stress-derived molecules have a role in the pathogenesis of HCV-MC vasculitis neuropathy.

Prevalence and characteristics of peripheral neuropathy in hepatitis C virus population

OBJECTIVE

To assess the prevalence of peripheral neuropathy (PN) and its correlation with cryoglobulinemia (CG) in an unselected, untreated referral hepatitis C virus (HCV) population.

PATIENTS AND METHODS

Two hundred and thirty four patients (120 women and 114 men) with untreated HCV infection were consecutively enrolled by seven Italian centres. Clinical neuropathy was diagnosed when symptoms and signs of peripheral sensory or motor involvement were present. Median, ulnar, peroneal, and sural nerves were explored in all patients and distal symmetric polyneuropathy was diagnosed when all explored nerves or both lower limb nerves were affected. Mononeuropathy and mononeuropathy multiplex were diagnosed when one nerve or two non-contiguous nerves with asymmetrical distribution were affected. Screening for CG was done in 191 unselected patients.

RESULTS

Clinical signs of PN were observed in 25 of the 234 patients (10.6%). Electrophysiological PN was found in 36 (15.3%). CG was present in 56/191 patients (29.3%). The prevalence of CG increased significantly with age (p<0.001) and disease duration (p<0.05). PN was present in 12/56 (21%) patients with CG and 18/135 (13%) without CG (p=NS). PN increased significantly with age (p<0.001) and logistic regression analysis confirmed age as the only independent predictor of PN (OR 1.10 for each year; 95% CI 1.04 to 1.15; p<0.001).

CONCLUSIONS

Electrophysiological examination detected subclinical neuropathy in 11 patients (4.7%). Statistical analysis showed that CG was not a risk factor for PN whereas PN prevalence increased significantly with age.

Mechanisms of immune regulation in the peripheral nervous system

The peripheral nervous system (PNS) is a target for heterogenous immune attacks mediated by different components of the systemic immune compartment. T cells, B cells, and macrophages can interact with endogenous, partially immune-competent glial cells and contribute to local inflammation. Cellular and humoral immune functions of Schwann cells have been well characterized in vitro. In addition, the interaction of the humoral and cellular immune system with the cellular and extracellular components in the PNS may determine the extent of tissue inflammation and repair processes such as remyelination and neuronal outgrowth. The animal model experimental autoimmune neuritis (EAN) allows direct monitoring of these immune responses in vivo. In EAN contributions to regulate autoimmunity in the PNS are made by adhesion molecules and by cytokines that orchestrate cellular interactions. The PNS has a significant potential to eliminate T cell inflammation via apoptosis, which is almost lacking in other tissues such as muscle and skin. In vitro experiments suggest different scenarios how specific cellular and humoral elements in the PNS may sensitize autoreactive T cells for apoptosis in vivo. Interestingly several conventional and novel immunotherapeutic approaches like glucocorticosteroids and high-dose antigen therapy induce T cell apoptosis in situ in EAN. A better understanding of immune regulation and its failure in the PNS may help to develop improved, more specific immunotherapies.

Cryoglobulinaemia vasculitis in patients coinfected with HIV and hepatitis C virus

OBJECTIVE

To describe mixed cryoglobulinaemia (MC) vasculitis in patients coinfected with hepatitis C virus (HCV) and HIV.

DESIGN

Retrospective multicentre study through the GERMIVIC Database of 4005 HIV/HCV-coinfected patients.

METHODS

The characteristics and outcome of 11 HIV/HCV-coinfected patients with MC vasculitis were analysed and compared with those of 118 HCV-infected patients with MC vasculitis.

RESULTS

The mean age was 46 years (SD, 14), with 82% male. The median initial CD4 cell count was 367 cells/microl (range, 252-846). After a mean follow-up of 44.4 months, two deaths (18%) were noted. Clinical manifestations of MC included polyneuropathy in seven (64%), purpura in four (36%), arthralgia in four (36%), and kidney involvement in three (27%). Six patients received combination treatment with interferon-alfa and ribavirin, three of whom had sustained HCV virological response and were complete clinical responders. Four patients received corticosteroids and two showed a partial clinical response. Regardless of the HIV virological response, antiretroviral therapy did not improve MC vasculitis. Compared with patients with HCV monoinfection, coinfected patients were younger (P < 0.001), more frequently male (P = 0.03), more frequently intravenous drug users (P < 0.001), had higher HCV viraemia (P = 0.004), higher liver necroinflammation (P = 0.03), higher gammaglobulinaemia (P < 0.001) and lower cryoglobulin level (P = 0.03). The clinical manifestations of MC vasculitis did not differ significantly between the two groups.

CONCLUSION

There was a beneficial effect of anti-HCV therapy for HIV/HCV-coinfected patients with MC vasculitis.

Involvement of chemokines and type 1 cytokines in the pathogenesis of hepatitis C virus-associated mixed cryoglobulinemia vasculitis neuropathy

OBJECTIVE

To examine the expression profiles of a large number of genes within typical vasculitic nerve lesions in patients with mixed cryoglobulinemia (MC) vasculitis in order to better characterize the molecules involved in cellular tissue activation and trafficking.

METHODS

The quantitative expression of 19 genes coding for cytokines, chemokines, and their receptors in the nerve lesions of 9 patients with hepatitis C virus (HCV)-associated MC vasculitis, 7 with idiopathic polyarteritis nodosa (PAN) (rheumatic disease controls), and 8 patients with noninflammatory idiopathic neuropathy (noninflammatory neuropathy controls) was assessed using a real-time reverse transcriptase-polymerase chain reaction procedure.

RESULTS

Compared with the noninflammatory controls, HCV-MC vasculitis patients had a significantly higher expression of Th1 cytokines in vasculitic nerve lesions (mean +/- SEM fold increase 33.7 +/- 11.6 for interferon-gamma and 7.2 +/- 1.9 for tumor necrosis factor alpha), whereas Th2 cytokines were absent (interleukin-4 [IL-4], IL-5, and IL-13) or were not significantly different (IL-10). Chemokines involved in T cell and monocyte trafficking were also significantly up-regulated in the HCV-MC vasculitis patients (mean +/- SEM fold increase 27.4 +/- 8.3 for macrophage inflammatory protein 1alpha [MIP-1alpha], 19.9 +/- 5.7 for MIP-1beta, and 7.2 +/- 1.5 for CXCR3). Compared with patients with idiopathic PAN, there was a trend toward higher expression of MIP-1alpha and CXCR3 in HCV-MC vasculitis patients (mean +/- SEM fold increase 27.4 +/- 8.3 versus 5.3 +/- 3.4 for MIP-1alpha and 7.2 +/- 1.5 versus 2.5 +/- 0.9 for CXCR3).

CONCLUSION

This study is the first to demonstrate a role of cellular immunity and Th1 lymphocytes in the pathogenesis of HCV-MC vasculitic nerve lesions.

Clinical spectrum of cryoglobulinaemic neuropathy

BACKGROUND AND OBJECTIVE

Cryoglobulinaemic neuropathy (CN) is probably common, as it is usually related to HCV infection. The aim of this study was to delineate the clinical spectrum of CN in a large series and to investigate the factors influencing its expression.

METHODS

Seventy one consecutive patients (12 men, 59 women), diagnosed as having CN on the basis of clinical features of neuropathy, clinical and serological findings of mixed cryoglobulinaemia, and exclusion criteria, were identified during a six year period. All patients underwent clinical examination, and electrophysiological and laboratory investigations.

RESULTS

Results of the patients with "pure" CN (n = 54) and those with comorbidities (n = 17) were evaluated separately. Of the former 76% had sensory neuropathy (including selective small fibre sensory neuropathy (SFSN) in 14 patients), 15% had sensorimotor polyneuropathy, and 9% had mononeuritis multiplex. The pattern of distribution was similar in the patients with comorbidities. In 30/54 patients, CN was the first manifestation of cryoglobulinaemia. Patients with mild cryoglobulinaemic syndrome had sensory neuropathy more frequently than patients with active syndrome (p < 0.001), in particular SFSN (p < 0.001). The latter group had more severe features, with significantly more cases of reduced or absent motor (p = 0.028) and sensory action potentials (p < 0.001), and a tendency towards higher Rankin scores (p = 0.06).

CONCLUSIONS

Sensory neuropathy, often in the form of SFSN, is by far the commonest form of CN. Cryoglobulinaemia should be vigorously investigated in the diagnosis of sensory neuropathy, especially in older women. Activity of the cryoglobulinaemic syndrome is a major factor influencing the clinical expression and severity of CN.

Peripheral neuropathy in hepatitis C virus infection with and without cryoglobulinaemia

OBJECTIVES

Hepatitis C virus (HCV) infection is often associated with cryoglobulinaemia (CG). Peripheral neuropathy (PN) is a comparatively common complication of CG associated with HCV infection and it is thought to be attributable to nerve ischaemia. Only few HCV CG patients with PN have been reported. The recent finding of HCV RNA in nerve biopsy specimens has suggested a possible direct role of HCV in the pathogenesis of PN. The authors studied 51 HCV patients to determine the prevalence of CG and to clarify the possible mechanism by which HCV determines the PN.

METHODS

All the patients were studied clinically, by laboratory tests and electrophysiologically. Twenty eight patients underwent sural nerve biopsy where both morphological and morphometric evaluation of the biopsy specimen was performed, as well as statistical analysis.

RESULTS

CG was found in 40 of 51 cases (78%). Polyneuropathy was significantly prevalent in CG+ patients compared with CG- (18 of 40 compared with 1 of 11 patients; p=0.01). HCV CG- patients more frequently developed well defined mononeuropathy or multiple neuropathy when compared with HCV CG+ (10 of 11 compared with 22 of 40; p<0.03). HCV CG+ patients showed significantly higher proportion of rheumatoid factor positivity (p<0.001) and low C4 levels (p=0.001). Nerve biopsy was performed in 25 of 40 HCV CG+ patients and in 3 of 11 HCV CG- patients: epineurial vasculitis was present in 8 of 25 HCV CG+ (32%) and in 2 of 3 HCV CG-. Differential fascicular loss of axons was found in 10 of 25 CG+ (40%) and 1 of 3 CG-, signs of both demyelination and axonal degeneration were present in 7 of 25 CG+ (28%). No significant difference was found in neuropathological features, while histometrical analysis disclosed more severe involvement in CG+ patients.

CONCLUSIONS

These findings suggest that the presence of CG is a negative predictive factor for the associated PN. Morphological findings in the sural nerve from HCV CG- and CG+ are consistent with an ischaemic mechanism of nerve damage and are against a direct role of the virus in causing the associated PN.

Microvasculitic paraproteinaemic polyneuropathy and B-cell lymphoma

Microvasculitis may play a greater part in the pathogenesis of paraproteinaemic neuropathies than is generally recognised, producing tissue destruction by convergent immune and physical mechanisms. We present a patient with a clinical syndrome of mononeuritis multiplex and a circulating IgM lambda paraprotein, in whom bone marrow aspiration revealed a lymphoplasmacytoid lymphoma. Microvasculitic changes were present in the first nerve biopsy, and the second showed extensive destruction of neural architecture and deposition of IgM-related material. A 2-stage pathogenic cascade is postulated and explored with a review of the relevant literature.

Viral RNA in nerve tissues of patients with hepatitis C infection and peripheral neuropathy

To assess the presence of viral ribonucleic acid (RNA) in nerve tissues of 15 patients with hepatitis C virus (HCV) infection and peripheral neuropathy with (11) or without (4) mixed cryoglobulinemia, nested reverse transcription-polymerase chain reaction (RT-PCR) was performed. Amplification of HCV-RNA was successful in 7 patients with and 3 without mixed cryoglobulinemia. This study demonstrates that the nested RT-PCR technique is a sensitive method to detect viral RNA in nerve tissue, and offers further evidence that in patients with HCV infection peripheral neuropathy can occur in the absence of mixed cryoglobulinemia.

Beyond neurons: evidence that immune and glial cells contribute to pathological pain states

Chronic pain can occur after peripheral nerve injury, infection, or inflammation. Under such neuropathic pain conditions, sensory processing in the affected body region becomes grossly abnormal. Despite decades of research, currently available drugs largely fail to control such pain. This review explores the possibility that the reason for this failure lies in the fact that such drugs were designed to target neurons rather than immune or glial cells. It describes how immune cells are a natural and inextricable part of skin, peripheral nerves, dorsal root ganglia, and spinal cord. It then examines how immune and glial activation may participate in the etiology and symptomatology of diverse pathological pain states in both humans and laboratory animals. Of the variety of substances released by activated immune and glial cells, proinflammatory cytokines (tumor necrosis factor, interleukin-1, interleukin-6) appear to be of special importance in the creation of peripheral nerve and neuronal hyperexcitability. Although this review focuses on immune modulation of pain, the implications are pervasive. Indeed, all nerves and neurons regardless of modality or function are likely affected by immune and glial activation in the ways described for pain.

Cryoglobulinemia is a frequent cause of peripheral neuropathy in undiagnosed referral patients

Cryoglobulinemia represents an emerging cause of peripheral neuropathy, especially in Southern Europe, in view of its relationship with hepatitis C virus infection. In a series of 100 consecutive referral patients with uncharacterized peripheral neuropathies, we systematically investigated cryoglobulinemia to assess its diagnostic yield. The most frequent diagnosis was hereditary neuropathy (33%), 29% were acquired neuropathies of different types, and no cause could be identified in 27%. Cryoglobulinemic neuropathy was diagnosed in 11 patients (7 women and 4 men), aged 54-77 (mean = 63.5 years), most presenting with sensory polyneuropathy, often asymmetrical. Cryoglobulin was also detected in 2 additional patients in whom a final diagnosis of non-Hodgkin lymphoma was made. Purpura was absent in 4 patients (and in 2 with lymphoma), or restricted to discrete manifestations in the remaining patients, which did not provide a clue to the diagnosis. Thus, search for cryoglobulin proves useful in a substantial number of undiagnosed peripheral neuropathies (11% to 13% in our series), even in the absence of typical skin lesions, and it is recommended as a first-line investigation in patients with unexplained neuropathy presenting in middle to older age.

Cryoglobulinemia

Cryoglobulinemia may be found in a spectrum of disorders spanning clear-cut-B-cell neoplastic states, in which cryoprecipitation manifests as ischemic or occlusive vasculopathy, to a variety of immune complex diseases, in which vasculitis or glomerulonephritis may occur. Symptomatic cryoglobulinemia is many diseases, driven by and driving antibody-antigen responses, hepatic dysfunction, lymphoproliferation, and immune complexes. Distinguishing features that cause only some cryoglobulins to be symptomatic, elucidating the pathogenic mechanisms of HCV in cryoglobulin formation, and devising better therapies and more systematic evaluation of existing therapies are among the challenges for the future. Prognostication and classification will continue to rely on Brouet's classification (types I, II, and III), but additional features will probably include the presence or absence of HCV, HCV factors (genotype, titer), coexisting infections, B-cell clone burden, host factors, and immune system interactions (B- and T-cell idiotype networks, cytokines). Although antiviral therapy is a reasonable option for HCV-associated cryoglobulinemia, not all patients are HCV-positive, and only 60% to 80% of HCV-positive patients respond to IFN. In addition, not all patients tolerate IFN, and in those who do, the response is often short-lived once the treatment is discontinued. Only creative strategies, systematically studied, will provide long-awaited solutions.

Hepatitis C virus genotypes and clinical features in hepatitis C virus-related mixed cryoglobulinemia

Mixed cryoglobulinemia is a systemic disease, almost always associated with hepatitis C virus infection and characterized by purpura and cutaneous vasculitis, asthenia, arthralgias, and often renal and neurological involvement. No significant differences have been described to date in mixed cryoglobulinemia patients with type 1, 2, or 3 hepatitis C virus infection with respect to symptoms, while a higher prevalence of genotype 2a has been reported in patients without clinical and biochemical signs of liver disease or with serum autoantibodies. We examined 33 hepatitis C virus-positive patients with mixed cryoglobulinemia to assess if any clinical or serological feature is related to infection with different genotypes. All subjects underwent viral genotype determination by means of a single-step polymerase chain reaction. Thirteen patients (39%) were infected with hepatitis C virus type 1b, 17 (52%) with type 2a or 2a/c, and 3 (9%) with type 3. There was a significant difference in the frequency of peripheral nervous system involvement: paresthesias or other symptoms of peripheral neuropathy were less frequent in patients with 2a or 2a/c infection (29%) than in patients with type 1b or type 3 infection (88%, P = 0.003). Only patients with hepatitis C virus type 2 had urticaria or cutaneous ulcers. These patients also had a lower frequency of arthralgias, lower cryocrit values (P = 0.02), and lower serum levels of alanine-aminotransferase and gamma-glutamyl-transpeptidase (P < 0.04) than patients with type 1 and type 3 infection. The prevalence of antinuclear antibody positivity was similar in the three groups.

Central nervous system involvement in patients with HCV-related cryoglobulinemia

Central nervous system involvement was rarely described in patients with mixed cryoglobulinemia (MC). Most cases were reported before 1991, so these patients were not tested for hepatitis C virus (HCV) infection. However, two cases of cerebral ischemia in patients with HCV-related MC were recently reported. We describe three patients with chronic HCV and cryoglobulinemia, who complained of mild neurologic symptoms (dizziness, equilibrium impairment, monolateral hyposthenia, and defective sensitivity) which can be ascribed to central nervous system involvement. In all of these patients, brain magnetic resonance imaging showed multiple small hyperintensities compatible with ischemic lesions.

Central nervous system involvement in patients with HCV-related cryoglobulinemia

Central nervous system involvement was rarely described in patients with mixed cryoglobulinemia (MC). Most cases were reported before 1991, so these patients were not tested for hepatitis C virus (HCV) infection. However, two cases of cerebral ischemia in patients with HCV-related MC were recently reported. We describe three patients with chronic HCV and cryoglobulinemia, who complained of mild neurologic symptoms (dizziness, equilibrium impairment, monolateral hyposthenia, and defective sensitivity) which can be ascribed to central nervous system involvement. In all of these patients, brain magnetic resonance imaging showed multiple small hyperintensities compatible with ischemic lesions.