Cytokine Levels in Neural Pain in Leprosy

Pain is a frequent symptom in leprosy patients. It may be predominantly nociceptive, as in neuritis, or neuropathic, due to injury or nerve dysfunction. The differential diagnosis of these two forms of pain is a challenge in clinical practice, especially because it is quite common for a patient to suffer from both types of pain. A better understanding of cytokine profile may serve as a tool in assessing patients and also help to comprehend pathophysiology of leprosy pain. Patients with leprosy and neural pain (n = 22), neuropathic pain (n = 18), neuritis (nociceptive pain) (n = 4), or no pain (n = 17), further to those with diabetic neuropathy and neuropathic pain (n = 17) were recruited at Souza Araujo Out-Patient Unit (Fiocruz, Rio de Janeiro, RJ, Brazil). Serum levels of IL1β, IL-6, IL-10, IL-17, TNF, CCL-2/MCP-1, IFN-γ, CXCL-10/IP-10, and TGF-β were evaluated in the different Groups. Impairment in thermal or pain sensitivity was the most frequent clinical finding (95.5%) in leprosy neuropathy patients with and without pain, but less frequent in Diabetic Group (88.2%). Previous reactional episodes have occurred in patients in the leprosy and Pain Group (p = 0.027) more often. Analysis of cytokine levels have demonstrated that the concentrations of IL-1β, TNF, TGF-β, and IL-17 in serum samples of patients having leprosy neuropathy in combination with neuropathic or nociceptive pain were higher when compared to the samples of leprosy neuropathy patients without pain. In addition, these cytokine levels were significantly augmented in leprosy patients with neuropathic pain in relation to those with neuropathic pain due to diabetes. IL-1β levels are an independent variable associated with both types of pain in patients with leprosy neuropathy. IL-6 concentration was increased in both groups with pain. Moreover, CCL-2/MCP-1 and CXCL-10/IP-10 levels were higher in patients with diabetic neuropathy over those with leprosy neuropathy. In brief, IL-1β is an independent variable related to neuropathic and nociceptive pain in patients with leprosy, and could be an important biomarker for patient follow-up. IL-6 was higher in both groups with pain (leprosy and diabetic patients), and could be a therapeutic target in pain control.

Anti-natural octyl disaccharide-leprosy IDRI diagnostic (NDO-LID) antibodies as indicators of leprosy reactions and neuritis

Background

Leprosy is a complex infectious and neurological disease caused by Mycobacterium leprae. Nerve damage is related to immunological hypersensitivity responses known as leprosy reactions (LRs). Diagnostic tools to predict LRs are not available. We hypothesized that natural octyl disaccharide-leprosy IDRI diagnostic (NDO-LID) would be helpful as an indicator of LRs and neuritis.

Methods

To assess the utility of NDO-LID in indicating reactions, ELISA were used to detect specific antibodies in serum samples from 80 Colombian leprosy patients (40 with and 40 without history of LRs). Responses were detected using a range of detection reagents detecting IgG, IgM or both isotypes.

Results

Patients with a history of LRs had an increased seropositivity rate for anti-NDO-LID antibodies compared to patients without (anti-NDO-LID protein A [p=0.02], IgG anti-NDO-LID [p=0.01] and IgM anti-NDO-LID [p=0.01]). Further analyses of patients with a history of LRs indicated that both seropositivity rate and magnitude of responses were elevated among patients with neuritis versus those without neuritis (anti-NDO-LID protein A [p=0.03], IgG anti-NDO-LID [p=0.001] and IgM anti-NDO-LID [p=0.06]).

Conclusions

Our data indicate that testing for serum anti-NDO-LID antibodies can be a useful screen to identify patients at risk of developing LRs and neuritis.

The somatostatin receptor 4 agonist J-2156 reduces mechanosensitivity of peripheral nerve afferents and spinal neurons in an inflammatory pain model

Somatostatin (SST) is a peptide hormone that regulates the endocrine system and affects neurotransmission via interaction with G protein-coupled SST receptors and inhibition of the release of different hormones. The aim of this study was to investigate whether the analgesic properties of the selective SSTR4 agonist J-2156 are mediated via peripheral and/or spinal receptors. Effect on mechanical hyperalgesia in the Complete Freund׳s Adjuvant (CFA) model was measured after intraperitoneal application of J-2156. Electrophysiological neuronal recordings were conducted 24 h after injection of CFA or vehicle into the paw of Wistar rats. Mechanosensitivity of peripheral afferents of the saphenous nerve as well as of spinal wide dynamic range (WDR) and nociceptive-specific (NS) neurons were measured after systemic or spinal application of J-2156. In CFA animals J-2156 dose dependently reduced hyperalgesia in behavioral studies. The minimal effective dose was 0.1 mg/kg. Mechanosensitivity of peripheral afferents and spinal neurons was significantly reduced by J-2156. NS neurons were dose dependently inhibited by J-2156 while in WDR neurons only the highest concentration of 100 µM had an effect. In sham controls, J-2156 had no effect on neuronal activity. We demonstrated that J-2156 dose-dependently reduces peripheral and spinal neuronal excitability in the CFA rat model without affecting physiological pain transmission. Given the high concentration of the compound required to inhibit spinal neurons, it is unlikely that the behavioral effect seen in CFA model is mediated centrally. Overall these data demonstrated that the analgesic effect of J-2156 is mediated mainly via peripheral SST4 receptors.

A case of acute thallotoxicosis successfully treated with double-filtration plasmapheresis

The authors report a 48-year-old Chinese woman who presented with acute peripheral neuritis with progressive alopecia. Laboratory examinations disclosed a high blood concentration of thallium (97 microg/L) versus a normal value (0.9 microg/L), and she was diagnosed as having acute thallotoxicosis. After her hospitalization, the cutantest of dimercaptopropansulfonate sodium was positive and the patient refused to take Prussian blue because it caused constipation. She rapidly entered remission after assistance via double-filtration plasmapheresis (DFPP), suggesting the potential efficacy of DFPP for thallotoxicosis.

Antibodies against the myelin oligodendrocyte glycoprotein and the myelin basic protein in multiple sclerosis and other neurological diseases: a comparative study

In experimental animal models of multiple sclerosis demyelinating antibody responses are directed against the myelin oligodendrocyte glycoprotein (MOG). We have investigated whether a similar antibody response is also present in multiple sclerosis patients. Using the recombinant human extracellular immunoglobulin domain of MOG (MOG-Ig) we have screened the sera and CSFs of 130 multiple sclerosis patients, 32 patients with other inflammatory neurological diseases (OIND), 30 patients with other non-inflammatory neurological diseases (ONND) and 10 patients with rheumatoid arthritis. We report that 38% of multiple sclerosis patients are seropositive for IgG antibodies to MOG-Ig compared with 28% seropositive for anti-myelin basic protein (MBP). In contrast, OIND are characterized by similar frequencies of serum IgG antibody responses to MOG-Ig (53%) and MBP (47%), whereas serum IgG responses to MOG-Ig are rare in ONND (3%) and rheumatoid arthritis (10%). Anti-MBP IgG antibodies, however, are a frequent finding in ONND (23%) and rheumatoid arthritis (60%). Our results provide clear evidence that anti-MOG-Ig antibodies are common in CNS inflammation. However, in OIND these antibody responses are transient, whereas they persist in multiple sclerosis. We demonstrate that the serum anti-MOG-Ig response is already established in early multiple sclerosis (multiple sclerosis-R0; 36%). In later multiple sclerosis stages frequencies and titres are comparable with early multiple sclerosis. In contrast, the frequency of anti-MBP antibodies is low in multiple sclerosis-R0 (12%) and increases during disease progression in relapsing-remitting (32%) and chronic progressive multiple sclerosis (40%), thus suggesting that anti-MBP responses accumulate over time. Finally we provide evidence for intrathecal synthesis of IgG antibodies to MOG-Ig in multiple sclerosis.

Heightened IgE response to mite antigens in inflammatory neuropathies

In order to clarify the IgE response to common environmental antigens, we measured the serum total IgE and allergen-specific IgE in 50 patients with Guillain-Barré syndrome (GBS), nine patients with Fisher syndrome (FS), 14 patients with chronic inflammatory demyelinating polyneuropathy (CIDP), 18 patients with mononeuritis multiplex (MNM), 43 patients with neurodegenerative disorders and 82 healthy controls by ELISA. The total IgE level was significantly higher in patients with GBS (median = 135 U/ml, P<0.05), CIDP (median = 175 U/ml, P<0.05) and MNM (median= 199 U/ml, P<0.05), than in the healthy controls (median = 79 U/ml), but not in those patients with neurodegenerative disorders. The specific IgE to Dermatophagoides pteronyssinus was significantly higher in the patients with GBS (56%, P<0.01) and MNM (72%, P<0.005) than in the healthy controls (32%). The level of specific IgE to Dermatophagoides farinae tended to be higher in the patients with GBS than in the healthy controls (0.05<P<0.1). The patients with CIDP and MNM also showed a similar increase in the frequency of mite antigen-specific IgE. As a result, the heightened IgE responses to mite antigens may therefore in part be related to the mechanism of inflammatory neuropathies. On the other hand, such heightened IgE responses in these inflammatory neuropathies may be a reflection of Th2 cell overactivity, which may induce an intense synthesis of autoantibodies against the peripheral nerves.

Peripheral GABAA receptor-mediated effects of sodium valproate on dural plasma protein extravasation to substance P and trigeminal stimulation

1. The GABA transaminase inhibitor and activator of glutamic acid decarboxylase, valproic acid is being used for the treatment of migraine. Its mechanism of action is unknown. We tested the effects of sodium valproate and GABAA-agonist muscimol on dural plasma protein ([125I]-bovine serum albumin) extravasation evoked by either unilateral trigeminal ganglion stimulation (0.6 mA, 5 ms, 5 Hz, 5 min) or substance P (SP) administration (1 nmol kg-1,i.v.) in anaesthetized Sprague-Dawley rats. 2. Intraperitoneal (i.p.) injection of sodium valproate or muscimol, but not baclofen (< or = 10 mg kg-1, i.p.) dose-dependently reduced dural plasma protein extravasation caused either by electrical trigeminal stimulation (ED50: 6.6 +/- 1.4 mg kg-1, i.p., and 58 +/- 18 micrograms kg-1, i.p. for valproate or muscimol, respectively) or by intravenous substance P administration (ED50: 3.2 +/- 1.4 mg kg-1, i.p. and 385 +/- 190 micrograms kg-1, i.p. for valproate or muscimol, respectively). 3. Valproate (6.6 mg kg-1, i.p.) or muscimol (58 micrograms kg-1, i.p.) had no effect on mean arterial blood pressure or heart rate when measured for 30 min after i.p. administration. 4. The GABAA-antagonist bicuculline (0.01 mg kg-1, i.p.) completely reversed the effect of valproate and muscimol on plasma extravasation following electrical stimulation or substance P administration, whereas the GABAB-receptor antagonist, phaclofen (0.01-1 mg kg-1, i.p.) did not. Bicuculline or phaclofen, given alone, did not alter the plasma extravasation response after either electrical stimulation or SP administration. 5. Valproate decreased plasma extravasation following substance P administration in adult animals, neonatally treated with capsaicin by a bicuculline-reversible mechanism. This suggests that GABAA receptors are not found primarily on those afferent neurones or fibres which are sensitive to capsaicin treatment in neonatal rats.6. We conclude that sodium valproate blocks plasma extravasation in the meninges through GABAA mediated postjunctional receptors probably within the meninges. The dosages required are comparable to those used clinically. Agonists and modulators at the GABAA receptor may become useful for the development of selective therapeutic agents for migraine and cluster headache.

Increased serum levels of ICAM-1, ELAM-1 and TNF-alpha in inflammatory disorders of the peripheral nervous system

Endothelial intercellular adhesion molecule-1 (ICAM-1) and glycoprotein E-selectin (ELAM-1) allow the homing of leukocytes to inflammation sites. A circulating form of ICAM-1 markedly increases in inflammatory CNS disorders. In the present study, the serum levels of ICAM-1, ELAM-1 and tumor necrosis factor-alpha (TNF-alpha) were measured in patients with acute (AIDP) and chronic (CIDP) inflammatory demyelinating polyneuropathies and cryoglobulinemic neuropathy (CGN). Immunoenzymometric assays revealed increased sICAM-1 levels in some of these patients; furthermore, high titres of ELAM-1 and TNF-alpha were detected in two patients with AIDP and one patient with CGN. Our data extend previous observations on inflammatory PNS disorders by showing that, in addition to ICAM-1, ELAM-1 also represents a useful marker of endothelial activation and that, taken together, the two molecules may serve as an indicator of specific pathogenetic mechanisms.

Serum and CSF levels of soluble intercellular adhesion molecule-1 (ICAM-1) in inflammatory neurologic diseases

Intercellular adhesion molecule-1 (ICAM-1), a cell surface receptor important for cellular interactions in immune responses, especially leukocyte trafficking into inflamed tissue, is released in a soluble form (sICAM-1) into the extracellular space. In this study, we measured sICAM-1 in paired serum and CSF samples from patients with inflammatory diseases of the nervous system (IND) and calculated a sICAM-1 index as a measure of the intrathecal release of ICAM-1. In comparison with noninflammatory neurologic disease (NIND) controls, we found increased sICAM-1 index levels in viral meningoencephalitis, bacterial meningitis and, to a lesser degree, multiple sclerosis but not in Guillain-Barré syndrome. Serial examination of viral meningoencephalitis patients in most cases showed a decrease of sICAM-1 index in parallel with falling cell counts and clinical improvement. Except for those in bacterial meningitis, sICAM-1 serum levels of IND patients were not significantly different from those of NIND controls. The increased intrathecal release of sICAM-1 in viral meningoencephalitis and bacterial meningitis most likely reflects activation of macrophages and lymphocytes and provides evidence for a strong local immune response that itself, in addition to the infectious agent, may damage nervous tissue.

Inhibitory actions of prostaglandin E1 on neurogenic plasma extravasation in rat airways

To determine whether neurogenic inflammation can be inhibited by prostaglandin E1 (PGE1), that is suggested to have an inhibitory effect on neuropeptide release from airway sensory nerves, we examined plasma extravasation in the airways of anesthetized rats in vivo with Evans blue due as a marker. Neurogenic inflammation was produced by an i.v. injection of capsaicin (100 micrograms/kg) or by antidromic electrical stimulation of the right vagus nerve (4 Hz, 1 ms, 4 V for 1 min). Capsaicin injection significantly increased leakage of dye in the trachea and main bronchi. Similar increases in leakage were seen in the trachea and right bronchus on electrical stimulation of the right vagus nerve. PGE1 (1-1000 micrograms/kg) inhibited the leakage induced by capsaicin in the trachea and bronchi concentration dependently with complete inhibition at a concentration of 1000 micrograms/kg. Likewise, PGE1 (1000 micrograms/kg) significantly inhibited electrical stimulation-induced leakage in the trachea and right bronchus (P less than 0.01). I.v. substance P (SP; 1 microgram/kg) increased Evans blue dye extravasation in the same way as the leakage induced by capsaicin and electrical stimulation but PGE1 (1000 micrograms/kg) failed to inhibit SP-induced leakage in the trachea and main bronchi (P greater than 0.20). These results suggest that PGE1 inhibits neurogenic plasma leakage by presynaptic inhibition of the release of neuropeptides from sensory nerves.

A cationic glycoprotein pattern in human serum and cerebrospinal fluid with pathological implications

Patterns of highly glycosylated proteins with mainly cationic isoelectric points, pH 6.5-9.5, were observed in serum and cerebrospinal fluid of patients with various disorders. Detection was performed after isoelectric focusing, using an immunoassay specific for digoxigenylated carbohydrate moieties of glycoconjugates. To our knowledge, these glycoproteins have not hitherto been described as regular serum proteins. The patterns were found among 7% of the patients studied (n = 400). Similar bands were not detectable in a reference group of 100 persons without clinical symptoms. The glycoprotein pattern was specific for each individual. The pathophysiological meaning of these glycoproteins as well as the basic biochemistry has not yet been evaluated. The glycoproteins, however, were shown to differ from immunoglobulin G, oligoclonal immunoglobulin G, paraprotein or from regular cationic serum protein. By comparison with standard glycoproteins a carbohydrate content of 30 +/- 10% was roughly suggested. The oligosaccharides contain probably sialic acid as evidenced by lectin binding. Although the diagnoses varied, 90% of the patients with this glycoprotein pattern had inflammatory processes.

On the possibility of differential diagnosis at elevated erythrocyte sedimentation rate by analysis of the concentrations of blood plasma proteins--a model study

An elevated erythrocyte sedimentation rate is generally regarded as an unspecific and mostly pathological indicator of inflammation or tumour. However, we have determined the concentrations of plasma/serum proteins that influence the erythrocyte sedimentation rate in numerous samples from several groups of patients with different diseases, including 2 forms of cancer. Equations have been developed by which the 1 h value of erythrocyte sedimentation rate can be expressed as the sum of disease-specific coefficients for each protein multiplied by the measured concentrations of the respective proteins. These equations are shown to be disease-specific with 64-93% probability. Such equations may thus form the basis for differential diagnosis.

Susceptibility and resistance to experimental autoimmune encephalomyelitis and neuritis in the guinea pig correlate with the induction of procoagulant and anticoagulant activities

Activation of macrophage procoagulant activity (MPCA) is involved in the manifestation of EAE and EAN in susceptible guinea pigs and provides a mechanism for the deposition of fibrin, which is a feature of histologic lesions of EAE. Peritoneal exudate cells (PEC) from susceptible (strain 13) guinea pigs immunized with either central or peripheral nervous tissue antigens produce procoagulant activity when incubated with the immunogen in vitro. The production of the procoagulant is quantitative and antigen-specific and is maximal at the time of clinical signs of the disease. After recovery, the production of procoagulant activity decreased. The MPCA test was able to discriminate the biochemical differences existing between chicken and mammalian peripheral nerve proteins, thus providing a quantitative and sensitive indicator of cell-mediated immunity in EAE and EAN. The autoimmune response to brain and nerve antigens in nonsusceptible (strain 2) guinea pigs was coincident with the antigen-specific production of a cell-bound anticoagulant activity by stimulated mononuclear cells. The production of anticoagulant activity followed the same sequence of time changes after immunization as that of the MPCA in susceptible guinea pigs, and high immunizing doses of nerve antigens induced high levels of anticoagulant activity. The same cells produced high levels of procoagulant when incubated with tuberculin or lipopolysaccharide. The recalcification time of normal plasma was prolonged by the anticoagulant, and the decreased clotting time of plasma induced by the procoagulant activity obtained by incubating sensitized strain 13 PEC with myelin basic protein was suppressed by the anticoagulant produced by culturing sensitized strain 2 PEC with myelin basic protein. Preliminary evidence indicates that the anticoagulant has properties similar to antithrombin III. The anticoagulant could play a role in the control of effector cell function, and therefore in recovery from clinical features of EAE and EAN in susceptible guinea pigs.

[Kinetics of peripheral leukocyte count and leukocyte adhesion to pulmonary capillary endothelium in experimental vagal neuritis]

It was disclosed in chronic experiments on rats with dextral vagus neuritis that reactive leucocytosis is wave-like in character. Variations in leucocytosis were inversely proportional to adhesiveness of the lung capillary endothelium with respect to leucocytes. The relationship between the number of circulatory leucocytes and adhesiveness of the capillary endothelium is not so pronounced in intact animals as compared to controls.

Experimental allergic neuritis. Ultrastructure of serum-induced myelin aberrations in peripheral nervous system cultures

Mature myelinated cultures of mouse dorsal root ganglia (sometimes grown in combination with spinal cord tissue) have been exposed to unheated and heated (complement-inactivated) serum from rabbits with experimental allergic neuritis (EAN). Experimental cultures were examined for periods ranging from several hours to approximately 2 weeks of exposure. Some cultures were exposed to EAN serum for approximately 1 week then returned to normal medium for examination of the reversibility of the lesions. Unheated EAN serum induced demyelination of peripheral nervous system fibers within 96 hours of exposure. Following removal of the EAN serum, affected fibers remyelinated. Heated EAN serum produced a type of myelin swelling identical with that described previously in spinal cord explants exposed to serum from rabbits with experimental allergic encephalomyelitis. The lamellar spacing of the peripheral nervous system meylin was increased to approximately 23 nm. and the normal bifilar intraperiod line was increased to four leaflets. Some hypermyelination was seen. The swelling was incompletely reversible following removal of the heated serum. These findings are discussed in terms of their relevance to immunemediated demyelination and peripheral neuropathy associated with the hypergammaglobulinemic states.

Lipid abnormalities in hereditary neuropathy. Part 3. Plasma and erythrocyte lipids of HMSN-III (Dejerine-Sottas disease)

Plasma glucosylceramide levels of 5 patients with Hereditary Motor and Sensory Neuropathy Type III (Dejerine-Sottas disease) were approximately 50% higher than in controls. Erythrocyte glucosylceramides, however, were within the range of normal values. Elevated plasma glucosylceramide levels provide further evidence that an abnormality of lipid metabolism may underlie this recessively inherited hypertrophic neuropathy. No abnormality was observed among other glycosphingolipid fractions. An altered sphingomyelin fatty acid composition and reduced phosphatidylcholine level was also found, but this may not be disease-specific.

Gamma-globulins patterns in CSF of inflammatory neurological diseases in tropical Africa

400 CSF electrophoreses were performed on Black West Africans (Ivory Coast) with inflammatory infections of the nervous system. In the normal state, the CSF of the Black African contains a higher concentration of gamma-globulins than the European (15.8% compared to 8--10%). This study permits us to confirm indirectly the classical idea of the extreme rarity of MS in tropical areas: an increase in the gamma-globulins of the CSF has been shown in 22% of the cases and the two principal responsible infections are trypanosomiasis (57.3%) and SSPE (16.8%). The oligoclonal distribution by various authors in trypanosomiases was not found. On the contrary, a nonclonal aspect of gamma-zone was constantly found (49/50). It is possible that the differences are in accordance with the different evolutionary phases of the disease, and that the oligoclonal distribution is a marker of the autoimmune state of the disease.

[Serum lipids in various polyneuropathies]

Serum lipids were determined in 40 cases of polyneuropathy including 17 cases of Charcot-Marie-Tooth peroneal muscular atrophy, 7 cases of Dejerine-Sot-tas polyneuropathy, 7 cases of Guillain-Barré syndrome, 2 cases of diabetic polyneuropathy, 2 cases of toxic polyneuropathy and 5 cases of polyneuropathy of unclear aetiology. In the studied material shifts were observed in the composition of serum lipids, in particular, sphingomyelin and cholesterol esters. No correlation was found beteen the type of lipid pattern changes and the clinical syndrome, type of histological changes in the sural nerve, the age at onset, as well as the duration of the disease. The probable mechanism of development of changes is discussed.