T helper type 2 like cytokine responses to peptides from P0 and P2 myelin proteins during the recovery phase of Guillain-Barré syndrome

Current Biomarker Strategies in Autoimmune Neuromuscular Diseases

Inflammatory neuromuscular disorders encompass a diverse group of immune-mediated diseases with varying clinical manifestations and treatment responses. The identification of specific biomarkers has the potential to provide valuable insights into disease pathogenesis, aid in accurate diagnosis, predict disease course, and monitor treatment efficacy. However, the rarity and heterogeneity of these disorders pose significant challenges in the identification and implementation of reliable biomarkers. Here, we aim to provide a comprehensive review of biomarkers currently established in Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating polyneuropathy (CIDP), myasthenia gravis (MG), and idiopathic inflammatory myopathy (IIM). It highlights the existing biomarkers in these disorders, including diagnostic, prognostic, predictive and monitoring biomarkers, while emphasizing the unmet need for additional specific biomarkers. The limitations and challenges associated with the current biomarkers are discussed, and the potential implications for disease management and personalized treatment strategies are explored. Collectively, biomarkers have the potential to improve the management of inflammatory neuromuscular disorders. However, novel strategies and further research are needed to establish clinically meaningful biomarkers.

Effect of fasudil on experimental autoimmune neuritis and its mechanisms of action

This study aimed to investigate the therapeutic effect of fasudil on treating experimental autoimmune neuritis (EAN). Twenty-four EAN mice were randomly assigned to fasudil treatment (Fasudil group) or saline treatment (EAN model group) for 28 days. Clinical symptom score was evaluated every other day; inflammatory cell infiltration, demyelination, anti-myelin basic protein (MBP), inflammatory cytokines, inducible nitric oxide synthase (iNOS), and arginase-1 were detected in sciatic nerves at day 28. Th1, Th2, Th17, and Tregs proportions in splenocytes were detected at day 28. Clinical symptom score was found to be attenuated in the Fasudil group compared to the EAN model group from day 12 to day 28. Sciatic nerve inflammatory cell counts by HE staining and demyelination by luxol fast blue staining were both reduced, while MBP was increased in the Fasudil group compared to the EAN model group at day 28. Interferon γ (IFN-γ) and interleukin (IL)-17 were reduced, while IL-4 and IL-10 were elevated in the Fasudil group at day 28. Sciatic nerve M1 macrophages marker iNOS was decreased while M2 macrophages marker arginase-1 was increased in the Fasudil group at day 28. CD4⁺IFN-γ⁺ (Th1) and CD4⁺IL-17⁺ (Th17) cell proportions were both decreased, CD4⁺IL-4⁺ (Th2) cell proportion was similar, while CD25+FOXP3+ (Treg) cell proportion in splenocytes was increased in the Fasudil group. In summary, fasudil presented a good therapeutic effect for treating EAN by attenuating Th1/Th17 cells and promoting Tregs activation as well as M2 macrophages polarization.

Biological Drugs in Guillain-Barré Syndrome: An Update

Background:

Guillain-Barré Syndrome (GBS) is currently considered the most common global cause of acute flaccid paralysis. Currently, standard therapy for Guillain-Barré Syndrome includes intravenous immunoglobulin or plasma exchange. Despite medical advances regarding these treatments, many treated patients do not reach full recovery. Therefore several biological agents have attracted the attentions from researchers during the last decades, and various studies have investigated their role in Guillain-Barré Syndrome.

Objective:

The present study aims to address emerging biological approaches to GBS while considering their efficiency and safety in treating the disease.

Materials and Methods:

An extensive electronic literature search was conducted by two researchers from April 2016 to July 2016. Original articles, clinical trials, systematic reviews (with or without meta-analysis) and case reports were selected. Titles and abstracts of papers were screened by reviewers to determine whether they met the eligibility criteria, and full texts of the selected articles were retrieved.

Results:

Herein authors focused on the literature data concerning emerging biological therapeutic agents, namely anti-C5 monoclonal antibody (Eculizumab), anti-C1q monoclonal antibody, anti-T cell monoclonal antibody, anti-CD2 monoclonal antibody, anti L-selectin monoclonal antibody, anti-CD20 monoclonal antibody (Rituximab), anti-CD52 monoclonal antibody (Alemtuzumab) and cytokine targets. By far, none of these agents have been approved for the treatment of GBS by FDA.

Conclusion:

Literature findings represented in current review herald promising results for using these biological targets. Current review represents a summary of what is already in regards and what progress is required to improve the immunotherapeutic approach of treating GBS via future studies.

Comprehensive cytokine profiling provides evidence for a multi-lineage Th responses in Guillain Barré Syndrome

Guillain Barré Syndrome (GBS) is one of the commonest acquired immune-mediated neuropathies, often preceded by infections. Although cellular immune responses are shown to substantially account for the pathophysiology of GBS, the precise mechanistic basis of risk and disease course remains enigmatic till date. Cytokines are best known for their abilities to drive cellular immunity and inflammation through their co-ordinated actions. Data obtained from clinical and animal model studies suggest important implications of some of the cytokines in the progression and recovery of GBS. However, these studies were performed on few cytokines and small set of GBS patients, thereby lacking a complete understanding of the patterns of association of cytokines representing Th1, Th2, and Th17 responses with GBS. We studied 65 well-characterized GBS patients and 73 age- and sex-matched healthy controls. A panel of 15 cytokines representing Th1, Th2 and Th17 pathways was assayed using Multiplex Suspension Array platform. Plasma levels of five cytokines were found to be altered in GBS patients compared to healthy control subjects: (i) IL-1β exhibited reduced levels, and (ii) IFN-γ, IL-4, IL-21 and IL-33 were elevated in GBS patients. The most important finding of this study was up-regulated expression of IL-21 and IL-33 in patients with GBS. Given the role of IL-33 as an alarmin, the elevated level of this cytokine provides important indication about a much broader role of cytokines in GBS. This study also provides evidence towards a multi-lineage Th cells (Th1, Th2 and Th17) associated cytokine responses in the pathophysiology of GBS.

Elispot assay detection of cytokine secretion in multiple sclerosis patients treated with interferon-b1a or glatiramer acetate compared with untreated patients

The mechanisms behind the beneficial effects of interferon-b1a (IFN-b1a) and glatiramer acetate (GA) in the treatment of multiple sclerosis (MS) are still uncertain. A ltered cytokine patterns have been suggested including inhibition of proinflammatory cytokines like interferon-g (IFN-g) and enhancement of anti-inflammato ry cytokines such as interleukin-4 (IL-4). Twenty-nine patients with MS (10 untreated, nine treated with IFN-b1a and 10 with GA) were investigated with elispot of peripheral blood mononuclear cells. Spontaneous and myelin induced (myelin basic protein (MBP), myelin oligodendro cyte glycoprotein (MO G)-14-39 and MO G 63-87) IFN-g, IL-4, IL-5 and IL-10 secretion was studied. We found a significant reduction of spontaneous IFN-g, IL-4 and IL-5, but no difference in IL-10 secreting cells in both groups of treated patients compared with the untreated patients. Myelin-specific responses showed a significant decrease of IFN-g and an increase of IL-5, but no change in IL-4 and IL-10 secreting cells in treated compared with untreated patients. Both treatment groups revealed similar cytokine secretion patterns except for a more pronounced decrease of both spontaneous and MO G 14-39 induced IL-4 secretion in the IFN-b1a treated group. Thus, immunological effects of IFN-b1a and G A were similar showing that disease promoting Th1 (IFN-g) cells were reduced while the potentially beneficial Th2 response (IL-4) was maintained.

Biomarkers of Guillain-Barré Syndrome: Some Recent Progress, More Still to Be Explored

Guillain-Barré syndrome (GBS), the axonal subtype of which is mainly triggered by C. jejuni with ganglioside-mimicking lipooligosaccharides (LOS), is an immune-mediated disorder in the peripheral nervous system (PNS) accompanied by the disruption of the blood-nerve barrier (BNB) and the blood-cerebrospinal fluid barrier (B-CSF-B). Biomarkers of GBS have been extensively explored and some of them are proved to assist in the clinical diagnosis and in monitoring disease progression as well as in assessing the efficacy of immunotherapy. Herein, we systemically review the literature on biomarkers of GBS, including infection-/immune-/BNB, B-CSF-B, and PNS damage-associated biomarkers, aiming at providing an overview of GBS biomarkers and guiding further investigations. Furthermore, we point out further directions for studies on GBS biomarkers.

Role of Campylobacter jejuni infection in the pathogenesis of Guillain-Barré syndrome: an update

Our current knowledge on Campylobacter jejuni infections in humans has progressively increased over the past few decades. Infection with C. jejuni is the most common cause of bacterial gastroenteritis, sometimes surpassing other infections due to Salmonella, Shigella, and Escherichia coli. Most infections are acquired due to consumption of raw or undercooked poultry, unpasteurized milk, and contaminated water. After developing the diagnostic methods to detect C. jejuni, the possibility to identify the association of its infection with new diseases has been increased. After the successful isolation of C. jejuni, reports have been published citing the occurrence of GBS following C. jejuni infection. Thus, C. jejuni is now considered as a major triggering agent of GBS. Molecular mimicry between sialylated lipooligosaccharide structures on the cell envelope of these bacteria and ganglioside epitopes on the human nerves that generates cross-reactive immune response results in autoimmune-driven nerve damage. Though C. jejuni is associated with several pathologic forms of GBS, axonal subtypes following C. jejuni infection may be more severe. Ample amount of existing data covers a large spectrum of GBS; however, the studies on C. jejuni-associated GBS are still inconclusive. Therefore, this review provides an update on the C. jejuni infections engaged in the pathogenesis of GBS.

Acute injury in the peripheral nervous system triggers an alternative macrophage response

BACKGROUND

The activation of the immune system in neurodegeneration has detrimental as well as beneficial effects. Which aspects of this immune response aggravate the neurodegenerative breakdown and which stimulate regeneration remains an open question. To unravel the neuroprotective aspects of the immune system we focused on a model of acute peripheral nerve injury, in which the immune system was shown to be protective.

METHODS

To determine the type of immune response triggered after axotomy of the sciatic nerve, a model for Wallerian degeneration in the peripheral nervous system, we evaluated markers representing the two extremes of a type I and type II immune response (classical vs. alternative) using real-time quantitative polymerase chain reaction (RT-qPCR), western blot, and immunohistochemistry.

RESULTS

Our results showed that acute peripheral nerve injury triggers an anti-inflammatory and immunosuppressive response, rather than a pro-inflammatory response. This was reflected by the complete absence of classical macrophage markers (iNOS, IFN γ, and IL12p40), and the strong up-regulation of tissue repair markers (arginase-1, Ym1, and Trem2). The signal favoring the alternative macrophage environment was induced immediately after nerve damage and appeared to be established within the nerve, well before the infiltration of macrophages. In addition, negative regulators of the innate immune response, as well as the anti-inflammatory cytokine IL-10 were induced. The strict regulation of the immune system dampens the potential tissue damaging effects of an over-activated response.

CONCLUSIONS

We here demonstrate that acute peripheral nerve injury triggers an inherent protective environment by inducing the M2 phenotype of macrophages and the expression of arginase-1. We believe that the M2 phenotype, associated with a sterile inflammatory response and tissue repair, might explain their neuroprotective capacity. As such, shifting the neurodegeneration-induced immune responses towards an M2/Th2 response could be an important therapeutic strategy.

The role of cytokines in Guillain-Barré syndrome

Cytokines play an important role in the pathogenesis of autoimmune diseases including Guillain-Barré syndrome (GBS) and its animal model experimental autoimmune neuritis (EAN). In this article, we reviewed the current knowledge of the role of cytokines such as TNF-α, IFN-γ, IL-1β, IL-6, IL-12, IL-18, IL-23, IL-17, IL-10, IL-4 and chemokines in GBS and EAN as unraveled by studies both in the clinic and the laboratory. However, these studies occasionally yield conflicting results, highlighting the complex role that cytokines play in the disease process. Efforts to modulate cytokine function in GBS and other autoimmune disease have shown efficiency indicating that cytokines are important therapeutic targets.

Tumor necrosis factor-alpha polymorphisms and expression in Guillain-Barré syndrome

Tumor necrosis factor-alpha (TNF-alpha) polymorphisms with increased expression is associated with many autoimmune and inflammatory diseases. Possible role of TNF-alpha polymorphism in the pathogenesis of Guillain-Barré syndrome (GBS) largely remains unknown. We investigated polymorphisms in the promoter region of TNF-alpha gene and its expression in GBS patients and healthy controls. TNF-alpha (-308 G>A, -857 C>T, and -863 C>A) polymorphisms in 140 GBS patients and 206 healthy controls were studied using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and allele specific-PCR. TNF-alpha level in serum by ELISA was determined in 60 patients and an equal number of controls. Prevalence of TNF-alpha -308 G > A polymorphic A allele was associated with increased risk of GBS (p < 0.001; OR = 2.58, 95% CI = 1.61-4.14). Heterozygous genotype (G/A) had an association with acute motor axonal neuropathy (p < 0.001; OR = 4.23, 95% CI = 2.00-8.95) and variant genotype A/A with both axonal subtypes, acute motor axonal neuropathy (p = 0.015, OR = 7.00, 95% CI = 1.46-33.57) and acute motor sensory axonal neuropathy (p = 0.017; OR = 7.73, 95% CI = 1.44-41.37). Variant genotype T/T of TNF-alpha -857 C>T polymorphism was also significantly associated with acute motor axonal neuropathy (p = 0.034; OR = 3.93, 95% CI = 1.11-13.91). Patients with A and T alleles had higher TNF-alpha level in serum. TNF-alpha -308 G > A and -857 C>T (only T/T) polymorphisms with increased TNF-alpha level may predict susceptibility to axonal subtypes of GBS.

Acute paretic syndrome in juvenile White Leghorn chickens resembles late stages of acute inflammatory demyelinating polyneuropathies in humans

Background

Sudden limb paresis is a common problem in White Leghorn flocks, affecting about 1% of the chicken population before achievement of sexual maturity. Previously, a similar clinical syndrome has been reported as being caused by inflammatory demyelination of peripheral nerve fibres. Here, we investigated in detail the immunopathology of this paretic syndrome and its possible resemblance to human neuropathies.

Methods

Neurologically affected chickens and control animals from one single flock underwent clinical and neuropathological examination. Peripheral nervous system (PNS) alterations were characterised using standard morphological techniques, including nerve fibre teasing and transmission electron microscopy. Infiltrating cells were phenotyped immunohistologically and quantified by flow cytometry. The cytokine expression pattern was assessed by quantitative real-time PCR (qRT-PCR). These investigations were accomplished by MHC genotyping and a PCR screen for Marek's disease virus (MDV).

Results

Spontaneous paresis of White Leghorns is caused by cell-mediated, inflammatory demyelination affecting multiple cranial and spinal nerves and nerve roots with a proximodistal tapering. Clinical manifestation coincides with the employment of humoral immune mechanisms, enrolling plasma cell recruitment, deposition of myelin-bound IgG and antibody-dependent macrophageal myelin-stripping. Disease development was significantly linked to a 539 bp microsatellite in MHC locus LEI0258. An aetiological role for MDV was excluded.

Conclusions

The paretic phase of avian inflammatory demyelinating polyradiculoneuritis immunobiologically resembles the late-acute disease stages of human acute inflammatory demyelinating polyneuropathy, and is characterised by a Th1-to-Th2 shift.

Distinct effector mechanisms in the development of autoimmune neuropathy versus diabetes in nonobese diabetic mice

NOD mice deficient for the costimulatory molecule B7-2 (NOD-B7-2KO mice) are protected from autoimmune diabetes but develop a spontaneous autoimmune peripheral neuropathy that resembles human diseases Guillain-Barre syndrome and chronic inflammatory demyelinating polyradiculoneuropathy. Similar observations have now been made in conventional NOD mice. We have shown previously that this disease was mediated by autoreactive T cells inducing demyelination in the peripheral nervous system. In this study, we analyzed the molecular pathways involved in the disease. Our data showed that neuropathy developed in the absence of perforin or fas, suggesting that classic cytotoxicity pathways were dispensable for nerve damage in NOD-B7-2KO mice. In contrast, IFN-gamma played an obligatory role in the development of neuropathy as demonstrated by the complete protection from disease and infiltration in the nerves in NOD-B7-2KO mice deficient for IFN-gamma. This result was consistent with the inflammatory phenotype of T cells infiltrating the peripheral nerves. Importantly, the relative role of perforin, fas, and IFN-gamma appears completely different in autoimmune diabetes vs neuropathy. Thus, there are sharp contrasts in the pathogenesis of autoimmune diseases targeting different tissues in the same NOD background.

Guillain-Barré syndrome

Guillain-Barré syndrome consists of at least four subtypes of acute peripheral neuropathy. Major advances have been made in understanding the mechanisms of some of the subtypes. The histological appearance of the acute inflammatory demyelinating polyradiculoneuropathy (AIDP) subtype resembles experimental autoimmune neuritis, which is predominantly caused by T cells directed against peptides from the myelin proteins P0, P2, and PMP22. The role of T-cell-mediated immunity in AIDP remains unclear and there is evidence for the involvement of antibodies and complement. Strong evidence now exists that axonal subtypes of Guillain-Barré syndrome, acute motor axonal neuropathy (AMAN), and acute motor and sensory axonal neuropathy (AMSAN), are caused by antibodies to gangliosides on the axolemma that target macrophages to invade the axon at the node of Ranvier. About a quarter of patients with Guillain-Barré syndrome have had a recent Campylobacter jejuni infection, and axonal forms of the disease are especially common in these people. The lipo-oligosaccharide from the C jejuni bacterial wall contains ganglioside-like structures and its injection into rabbits induces a neuropathy that resembles acute motor axonal neuropathy. Antibodies to GM1, GM1b, GD1a, and GalNac-GD1a are in particular implicated in acute motor axonal neuropathy and, with the exception of GalNacGD1a, in acute motor and sensory axonal neuropathy. The Fisher's syndrome subtype is especially associated with antibodies to GQ1b, and similar cross-reactivity with ganglioside structures in the wall of C jejuni has been discovered. Anti-GQ1b antibodies have been shown to damage the motor nerve terminal in vitro by a complement-mediated mechanism. Results of international randomised trials have shown equivalent efficacy of both plasma exchange and intravenous immunoglobulin, but not corticosteroids, in hastening recovery from Guillain-Barré syndrome. Further research is needed to discover treatments to prevent 20% of patients from being left with persistent and significant disability.

T cell reactivity to P0, P2, PMP-22, and myelin basic protein in patients with Guillain-Barre syndrome and chronic inflammatory demyelinating polyradiculoneuropathy

OBJECTIVES

It has been suggested that autoimmunity to peripheral myelin proteins is involved in the pathogenesis of Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). We aimed to compare reactivity of peripheral blood mononuclear cells (PBMC) to antigens of peripheral myelin proteins in patients with GBS and patients with CIDP with that of healthy controls and patients with other non-immune mediated neuropathies (ON).

METHODS

We prepared PBMC from blood from 83 healthy controls and from 64 patients with GBS, 54 with CIDP, and 62 with ON. PBMC were tested in antigen specific proliferation assays against peptides from myelin proteins P0, P2, PMP22, and myelin basic protein (MBP), which is identical to myelin P1, and against whole human MBP. Interferon-gamma (IFN-gamma) and interleukin (IL)-5 enzyme linked immunospot (ELISPOT) assays were also performed in some subjects to assess spontaneous and peripheral myelin antigen specific PBMC cytokine secretion.

RESULTS

Antigen specific PBMC proliferation assays showed no significant elevation of peptide specific T cell responsiveness in patients with GBS or CIDP compared with healthy controls or patients with ON. Levels of spontaneous ELISPOT IFN-gamma secretion were increased in patients with GBS and significantly increased in those with CIDP compared with healthy controls and patients with ON. No convincing differences in antigen specific ELISPOT IFN-gamma secretion levels to individual peptides were detectable in patients with GBS. The proportion of patients with CIDP with an increased number of PBMC producing IFN-gamma in response to peptide PMP-22(51-64) was significantly increased compared with healthy controls and patients with ON. No significant differences in antigen specific ELISPOT IL-5 secretion levels were detectable in patients with GBS or CIDP compared with controls, but levels of spontaneous IL-5 secretion were significantly higher in patients with CIDP than in healthy controls or patients with ON.

CONCLUSIONS

Although the lack of significantly increased antigen specific PBMC proliferation in GBS and CIDP does not support a role for T cells, the more sensitive ELISPOT technique detected increased numbers of PBMC secreting IFN-gamma spontaneously in 25% of patients with GBS, providing further evidence for a role of T cells in the immunopathology of GBS. Increased numbers of spontaneous IFN-gamma and IL-5 secreting cells, and increased IFN-gamma secretion in response to PMP-22(51-64), in patients with CIDP provide further evidence for a role of myelin specific T cells in CIDP.

Elevated number of cells secreting transforming growth factor beta in Guillain-Barre syndrome

We used ELISPOT and cell ELISA to study secretion of IL-4, IFN-gamma, TGF-beta, IL-6, and TNF-alpha by circulating mononuclear cells during the course of Guillain-Barré syndrome (GBS). Compared to healthy controls, patients with GBS had higher numbers of TGF-beta-secreting cells and the number of individuals with myelin-peptide-induced IL-4 and TGF-beta secretion was higher in the GBS group. No significant differences were seen concerning the predominantly pro-inflammatory cytokines IFN-gamma, IL-6 or TNF-alpha. Our findings indicate a down-regulatory role for TGF-beta and IL-4 in GBS.

Suppression of experimental autoimmune neuritis by ABR-215062 is associated with altered Th1/Th2 balance and inhibited migration of inflammatory cells into the peripheral nerve tissue

The therapeutic effects of ABR-215062, which is a new immunoregulator derived from Linomide, have been evaluated in experimental autoimmune neuritis (EAN), a CD4(+) T cell-mediated animal model of Guillain-Barré syndrome in man. In previous studies, we reported that Linomide suppressed the clinical EAN and myelin antigen-reactive T and B cell responses. Here EAN induced in Lewis rats by inoculation with peripheral nerve myelin P0 protein peptide 180-199 and Freund's complete adjuvant was strongly suppressed by ABR-215062 administered daily subcutaneously from the day of inoculation. ABR-215062 dose-dependently reduced the incidence of EAN, ameliorated clinical signs and inhibited P0 peptide 180-199-specific T cell responses as well as also the decreased inflammation and demyelination in the peripheral nerves. The suppression of clinical EAN was associated with inhibition of the inflammatory cytokines IFN-gamma and TNF-alpha, as well as the enhancement of anti-inflammatory cytokine IL-4 in lymph node cells and periphery nerve tissues, respectively, in a dose-dependent manner. These effects indicate that ABR-215062 may mediate its effects by regulation of Th1/Th2 cytokine balance and suggest that ABR-215062 is potentially a new chemical entity for effective treatment of autoimmune diseases.

Spontaneous secretion of interleukin-4, interleukin-10 and interferon-gamma by first trimester decidual mononuclear cells

PROBLEM

A T-helper cell type 2 (Th2) cytokine dominated microenvironment has been predicted to be crucial for successful pregnancy. However, little information is available about local cytokine secretion in the human decidua. We determined the spontaneous secretion of interleukin-4 (IL-4), interferon-gamma (IFN-gamma) and IL-10 by decidual mononuclear cells at the single cell level and compared it with their secretion by peripheral blood mononuclear cells (PBMC) in the first trimester of pregnancy.

METHODS OF STUDY

The cytokine secretion from decidual and blood cells was detected by a sensitive enzyme-linked immunosorbent spot-forming cell (ELISPOT)-assay.

RESULTS

Cells secreting IL-4 (median 153, range 8-530), IL-10 (median 188, range 32-1600) and IFN-gamma (median 123, range 15-1140) were detected in all decidual and blood samples. The cytokine secretion showed a co-linear pattern in both the blood and decidua, i.e. when one cytokine was secreted at high levels, the others followed the trend. No correlation was found between the number of cytokine secreting cells in blood and decidua for any of the cytokines.

CONCLUSIONS

Interleukin-4 and IL-10 are locally secreted in the decidua early during normal pregnancy, probably counteracting the fetal rejecting effects of co-expressed IFN-gamma. The cytokine secretion by blood cells does not generally reflect the local secretion pattern during first trimester pregnancy.

Detection of spontaneous and antigen-induced human interleukin-4 responses in vitro: comparison of ELISPOT, a novel ELISA and real-time RT-PCR

Interleukin-4 (IL-4) is an important T-helper cell type 2 (Th2) cytokine in man, driving Th2 polarisation and exerting the most antagonistic effects to the Th1 cytokine interferon-gamma (IFN-gamma). Nevertheless, few data on spontaneous and antigen-specific secretion of IL-4 in man are available, mainly due to difficulties in the detection of IL-4. In this study, we compared three assays that can detect antigen-induced IL-4 responses; ELISPOT, ELISA after blocking the IL-4 receptor during cell culture, and real-time reverse transcription polymerase chain reaction (RT-PCR). Spontaneous, antigen- and allergen-induced responses were analysed in peripheral blood mononuclear cells from three groups with different secretion patterns for IL-4: atopic individuals, nonatopic individuals and pregnant women. ELISPOT displayed the highest sensitivity and was the only assay that could detect spontaneous secretion of IL-4 in all analysed samples. The IL-4 receptor blocking ELISA was considered best for the detection of in vitro antigen- and allergen-induced responses, since the results obtained from the ELISPOT and real-time RT-PCR displayed lower specificity, possibly because of seemingly aberrant IL-4 responses in the group of pregnant women. The real-time RT-PCR for detection of IL-4 mRNA proved to be sensitive, but expression of IL-4 mRNA was not correlated with the secretion of IL-4.

Thyroid specific T helper cell analysis by ELISPOT assay with thyrotropin receptor (TSH-R) peptides

We previously reported that a synthetic peptide induced humoral autoimmunity to thyrotropin receptor (TSH-R) and the expansion of antigen-specific type 2 helper T (Th2) cell population in mice. The peptide corresponds to the human TSH-R C-terminal region. In the present study, we undertook a similar approach in patients with Graves' disease (GD). Peripheral lymphocytes from 5 healthy controls and 11 GD patients were prepared and analyzed for cytokines from helper T cells by an antigen specific enzyme-linked immuno spot (ELISPOT) assay. In GD patients, the total number of IL-4 producing cells increased significantly and the number of interferon-gamma(IFN-gamma) producing cells decreased. Further, co-incubation with several of the 20 kinds of TSH-R extracellular peptides increased the number of IL-4 producing cells in patients with GD. Such stimulatory peptides appear frequently in a TSH-R sequence. These peptides did not affect the numbers of IFN-gamma producing cells significantly. These results indicated that GD patients have an expanded Th2 population responding to TSH-R and the dominance of the humoral immune system in such patients.

Th2 shift in mononeuritis multiplex and increase of Th2 cells in chronic inflammatory demyelinating polyneuropathy: an intracellular cytokine analysis

To elucidate the T helper 1 (Th1)/T helper 2 (Th2) balance in various inflammatory neuropathies, we measured the ratio of intracellular interferon-gamma (IFN-gamma)-positive to IL-4-positive cells (intracellular IFN-gamma/IL-4 ratio) by flow cytometry in peripheral blood CD4(+) T cells of 14 patients with mononeuritis multiplex (MNM), 12 patients with chronic inflammatory demyelinating polyneuropathy (CIDP), 10 patients with Guillain-Barré syndrome (GBS), 23 patients with neurodegenerative disorders and 36 healthy controls by intracellular labeling. The patients with MNM showed a significantly lower intracellular IFN-gamma/IL-4 ratio (P<0.05) and higher IL-4(+)/IFN-gamma(-) cell percentages (P<0.05) than the controls. The increase of IL-4(+)/IFN-gamma(-) cell percentages was especially prominent in MNM of unknown etiology (P<0.005). The patients with CIDP also showed significantly higher IL-4(+)/IFN-gamma(-) cell percentages (P<0.05) than the controls. The IL-4(+)/IFN-gamma(-) cell percentages were increased in some patients with GBS, but the difference was not significant compared with the controls. Thus, our results suggest that a Th2 shift is a characteristic of MNM and may play an important role in the development of the disease.

Cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) blockade enhances incidence and severity of experimental autoimmune neuritis in resistant mice

Experimental autoimmune neuritis (EAN), an autoimmune inflammatory demyelinating disease of the peripheral nervous system, represents an animal model of the human Guillain-Barré syndrome. EAN can be induced by active immunization in several animals, including Lewis rats. In contrast, most strains of mice including the widely used C57BL/6 (B6) strain are reputedly resistant to the induction of EAN. In the present study, we demonstrate that in B6 mice, anti-CTLA-4 monoclonal antibody administration in conjunction with immunization with the P0 protein derived peptide 180-199 can induce clinical and pathological definite EAN. Upregulating effects of CTLA-4 blockade on initial and ongoing EAN are demonstrated. CTLA-4 blockade augmented cellular infiltration and enhanced demyelination in the target organ sciatic nerves as well as increased T cell proliferation in lymph node cells. Moreover, serum levels of IFN-gamma and IL-4 were increased. Thus, manipulation of CTLA-4/B7 costimulatory pathway by CTLA-4 blockade can promote autoreactivity and break the relative tolerance to peripheral autoantigen P0 in resistant B6 mice.

Transfer of myelin-specific cells deviated in vitro towards IL-4 production ameliorates ongoing experimental allergic neuritis

A causal role of IL-4 (Th2) production for recovery in experimental allergic neuritis (EAN) was indicated by experiments where Th1-like autoreactive cell populations, taken from the induction phase of the disease, were deviated to extensive secretion of IL-4 in a selective fashion, by ex vivo stimulation with autoantigen in the presence of IL-4. The deviated cells were adoptively transferred to EAN rats at a time just prior to the onset of clinical signs. This treatment ameliorated EAN compared with sham treatment. This therapeutic approach, with generation of autoreactive IL-4-secreting cells ex vivo followed by subsequent adoptive transfer, may become a new selective treatment of organ-specific autoimmune diseases since, in contrast to previous attempts, it is done in a physiological and technically easy way.

IL-10 and IFN-gamma in Guillain-Barré syndrome. Network Members of the Swedish Epidemiological Study Group

Guillain-Barré syndrome (GBS) is an acute inflammatory disease affecting myelin and axons of the peripheral nervous system (PNS). GBS is considered to be caused by breakdown of tolerance to autoantigens of the PNS. The involvement of cytokines in GBS and in relation to treatment with high dose intravenous immunoglobulin (IvIg) is incompletely known. We studied the temporal profiles of IL-10 and IFN-gamma-secreting blood mononuclear cells (MNC) over the course of GBS, using enzyme-linked immunospot (ELISPOT) assays. Pretreatment levels of blood MNC spontaneously secreting IL-10 were higher in the acute phase of GBS than in control patients with aseptic meningitis, other neurological diseases, diabetic neuropathy and healthy subjects. Levels of IFN-gamma-secreting blood MNC were not increased over the course of GBS. Patients treated with IvIg had lower numbers of IL-10-secreting MNC compared to untreated patients. High levels of IL-10-secreting MNC correlated with serum anti-ganglioside IgM antibody levels, and with neurophysiological signs of axonal damage. The present data suggests that IFN-gamma is not involved in GBS pathogenesis, and IL-10 being up-regulated in the early phase of GBS and associated with axonal damage, may have a pathogenetic role in GBS.

Novel therapeutic approaches to Guillain-Barré syndrome

Guillain-Barré syndrome is an autoimmune disease which occurs throughout the world. Whilst the majority of patients can expect a reasonable recovery, about 10% die and 10% are left disabled with current therapy. The standard treatment is a five day course of iv. immunoglobulin, given at a dose of 0.4 g/kg/day, with plasma exchange as an equally efficacious alternative. Steroids are ineffective in Guillain-Barré syndrome. All new potential therapeutic agents need to be tested in addition to the standard agents available. Future potential therapies are suggested by the study of the animal model experimental autoimmune neuritis in the Lewis rat. Whilst in theory it is possible to target the different stages of the immune response, in practice not all of the steps at which experimental autoimmune neuritis can be prevented will be translatable to human Guillain-Barré syndrome. This is because Guillain-Barré syndrome probably presents after the immune reaction has been ongoing for some time and therefore early aspects of the immune response cannot be prevented. Many of the possible measures would have widespread immunosuppressive effects which would be unacceptable to patients. Interfering with the immune response by attempting to block antigen binding or inducing tolerance may not be practical, owing to the possibility of exacerbating disease. Once we have a more thorough understanding of the pathogenesis of Guillain-Barré syndrome, then immune-specific therapy for Guillain-Barré syndrome may become a possibility, rather than general immunosuppressive measures. Trials of beta-interferon and of a combination of steroid and i.v. immunoglobulin are underway. A trial of a second course of i.v. immunoglobulin is planned.

Protective effect of Rolipram in experimental autoimmune neuritis: protection is associated with down-regulation of IFN-gamma and inflammatory chemokines as well as up-regulation of IL-4 in peripheral nervous system

Rolipram, a phosphodiesterase type 4 inhibitor, is reported to have anti-inflammatory effects. It can markedly downregulate antigen-driven T cell proliferation and suppress TNF-(alpha and TNF-beta production in vitro and in vivo, which have led to its use in the treatment of a number of autoimmune disorders including experimental autoimmune encephalomyelitis (EAE) and experimental autoimmune neuritis (EAN). EAN is a CD4+ T cell-mediated demyelinating autoimmune disease of peripheral nervous system (PNS) that represents an animal model for the study of the immunopathogenesis and immunotherapy of Guillain-Barré syndrome (GBS) in human. In the previous study, we reported that suppression of EAN by Rolipram was associated with down-regulated myelin antigen-induced T cell responses as well as downregulated IFN-gamma and TNF-alpha production. Here we report that EAN induced in Lewis rats by inoculation with the PNS P2 protein peptide 57-81 and Freund's complete adjuvant (FCA), was strongly suppressed by Rolipram administered twice daily intraperitoneally from day 9 post immunization (p.i.), i.e. after onset of clinical EAN to day 18 p.i. This clinical effect was associated with dose-dependent down-regulated production of IFN-gamma and the chemokines macrophage inflammatory protein-1 alpha (MIP-1 alpha, MIP-2 and monocyte chemotactic protein-1(MCP-1) as well as up-regulated IL-4 production in sciatic nerve sections from Rolipram-treated EAN rats at maximum of clinical EAN, i.e. on day 14 p.i.. These findings suggest that Rolipram may be useful in certain T cell-dependent autoimmune diseases and inflammatory neuropathies. These observations call for further studies on the potential role of Rolipram in the treatment of autoimmune diseases.

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.

Asymptomatic Borrelia-seropositive individuals display the same incidence of Borrelia-specific interferon-gamma (IFN-gamma)-secreting cells in blood as patients with clinical Borrelia infection

Borrelia Lyme disease is a complex disorder that sometimes becomes chronic. There are contradictory reports of experimental Borrelia infections regarding which type of T cell cytokine responses, i.e. Th1 or Th2, are needed to eradicate the Borrelia spirochaetes. In human borreliosis a predominance of Borrelia-specific Th1-like responses has been shown. In this study, spontaneous, as well as Borrelia-specific, secretion of IFN-gamma (Th1) and IL-4 (Th2) in Borrelia-seropositive healthy asymptomatic individuals (n = 17) was investigated in peripheral blood by a sensitive ELISPOT assay, and compared with previously reported responses in patients with clinical Borrelia infection (n = 25). The seropositive asymptomatic individuals displayed the same predominance of Borrelia-specific IFN-gamma-secreting cells as the patients with clinical Borrelia infection. Interestingly, the proportion of spontaneously IL-4-secreting cells, reflecting the unstimulated in vivo secretion, was lower in the seropositive asymptomatic individuals compared with patients with chronic Borrelia infections (n = 13, P = 0.02), whereas no such difference was found compared with subacute Borrelia infections (n = 12). These findings indicate that IFN-gamma secretion alone is not sufficient to eliminate Borrelia spirochaetes in humans, although IFN-gamma may still have a beneficial role in borreliosis acting in concert with other mechanisms.

Expansion of helper T-cell recognition in mice immunized with a synthetic peptide corresponding to the C-terminal thyrotropin receptor-specific insert

We previously reported that immunization with a synthetic peptide of human thyrotropin receptor (TSH-R) expanded humoral autoimmunity to TSH-R (Sugawa H, Ueda Y, Ueda M, Kosugi S, Ichiyama S, Mori T. Immunization with the 'immunogenic Peptide' of TSH receptor induces oligoclonal antibodies with various biological activities. Peptide 1998;19:1303-7.). In the present study, we examined this phenomenon at the T-cell level. Balb/c mice were immunized with a synthetic peptide corresponding to the C-terminal-specific insert of human TSH-R. Spleen cells were collected and subjected to antigen-specific ELISPOT assay. The number of interleukin 4-secreting cells specific to P354-367 increased within 3 weeks. Cells responding to the other peptides increased 7 weeks after immunization. This phenomenon was not observed in mice immunized with bovine serum albumin alone. During immunization, numbers of interferon-gamma-secreting lymphocytes were not changed significantly. These results indicated that immunization with C-terminal TSH-R-specific insert peptide causes fluctuation in the type 2 helper T-cell population but not type 1 Th cells against the TSH-R, and the recognition repertoire of type 2 helper T cell was expanded by the peptide.

Increased numbers of circulating interferon-gamma- and interleukin-4-secreting cells during normal pregnancy

PROBLEM

Systemic immune responses during normal pregnancy are suggested to deviate toward secretion of T helper (Th)2-like cytokines.

METHOD OF STUDY

Blood samples from 11 healthy primigravidae in their first, second, and third trimesters, and 8 weeks postpartum were examined. Peripheral blood mononuclear cells were separated and the numbers of interferon (IFN)-gamma- and interleukin (IL)-4-secreting cells were identified by using the enzyme-linked immunospot test.

RESULTS

In all three trimesters of pregnancy, and also postpartum, the numbers of IFN-gamma- and IL-4-secreting cells were significantly higher compared with nonpregnant controls (Mann-Whitney; P < 0.001). The numbers of IFN-gamma- and IL-4-secreting cells gradually increased as the pregnancy progressed compared with postpartum (Kruskas-Wallis; P < 0.01 and P < 0.05, for IFN-gamma and IL-4, respectively). The ratios of IFN-gamma/IL-4 during pregnancy and postpartum were unchanged, and also when compared with nonpregnant controls.

CONCLUSION

The results indicate a systemic up-regulation of both Th1- and Th2-like immune responses during normal pregnancy.

Compartmentalization of antigen specific cytokine responses to the central nervous system in CNS borreliosis: secretion of IFN-gamma predominates over IL-4 secretion in response to outer surface proteins of Lyme disease Borrelia spirochetes

The neurological manifestations of Lyme disease have been proposed to be partly due to cytokine-mediated immunopathological mechanisms. In this study, the number of Borrelia-specific cells secreting interferon-gamma and interleukin-4 was determined in blood and cerebrospinal fluid from patients with CNS borreliosis (n = 23), other neurological diseases (n = 20), and in blood from healthy controls (n = 10), utilizing an ELISPOT-assay. Elevated specific secretion of IFN-gamma was found in CNS borreliosis, most pronounced in cerebrospinal fluid, whereas secretion of IL-4 was strikingly low. This may indicate that symptoms are due to side effects of the immune response, since IFN-gamma secretion in the absence of corresponding levels of IL-4 may be associated with tissue destruction.