Increased mRNA expression of IL-10 in mononuclear cells in multiple sclerosis and optic neuritis

Endogenous interferon-β-inducible gene expression and interferon-β-treatment are associated with reduced T cell responses to myelin basic protein in multiple sclerosis

Autoreactive CD4⁺ T-cells are considered to play a major role in the pathogenesis of multiple sclerosis. In experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis, exogenous and endogenous type I interferons restrict disease severity. Recombinant interferon-β is used for treatment of multiple sclerosis, and some untreated multiple sclerosis patients have increased expression levels of type I interferon-inducible genes in immune cells. The role of endogenous type I interferons in multiple sclerosis is controversial: some studies found an association of high expression levels of interferon-β-inducible genes with an increased expression of interleukin-10 and a milder disease course in untreated multiple sclerosis patients, whereas other studies reported an association with a poor response to treatment with interferon-β. In the present study, we found that untreated multiple sclerosis patients with an increased expression of interferon-β-inducible genes in peripheral blood mononuclear cells and interferon-β-treated multiple sclerosis patients had decreased CD4⁺ T-cell reactivity to the autoantigen myelin basic protein ex vivo. Interferon-β-treated multiple sclerosis patients had increased IL10 and IL27 gene expression levels in monocytes in vivo. In vitro, neutralization of interleukin-10 and monocyte depletion increased CD4⁺ T-cell reactivity to myelin basic protein while interleukin-10, in the presence or absence of monocytes, inhibited CD4⁺ T-cell reactivity to myelin basic protein. Our findings suggest that spontaneous expression of interferon-β-inducible genes in peripheral blood mononuclear cells from untreated multiple sclerosis patients and treatment with interferon-β are associated with reduced myelin basic protein-induced T-cell responses. Reduced myelin basic protein-induced CD4⁺ T-cell autoreactivity in interferon-β-treated multiple sclerosis patients may be mediated by monocyte-derived interleukin-10.

Cytokine profile in relapsing‑remitting multiple sclerosis patients and the association between progression and activity of the disease

Multiple sclerosis (MS) is a progressive immune‑ mediated disease caused by demyelination of the central nervous system. Cytokines and their receptors have an important role in the evolution of MS lesions, and pro‑ and anti‑inflammatory cytokine levels have been found to correlate with changes in MS disease activity. The aims of the present study were to evaluate the pro‑inflammatory [tumor necrosis factor (TNF)‑α and interleukin (IL) ‑1β, ‑6 and ‑12], T helper (Th) 1 [interferon (IFN)‑γ], Th17 (IL‑17) and Th2 (IL‑4 and ‑10) cytokine serum levels in relapsing‑remitting (RR)‑MS patients and to evaluate the association between the cytokine profile and the progression and activity of the disease. Serum cytokine levels were assessed using enzyme linked‑immunosorbent assays in 169 RR‑MS patients in the remission clinical phase and 132 healthy individuals who were age‑, gender‑, ethnicity‑ and body mass index‑matched. Disability and activity of the disease were evaluated using the Expanded Disability Status Scale and magnetic resonance imaging with gadolinium, respectively. IFN‑γ and IL‑6, ‑12 and ‑4 levels were higher in RR‑MS patients compared to controls (P=0.0009, 0.0114, 0.0297 and 0.0004, respectively). IL‑1 levels were higher in controls compared with RR‑MS patients. IL‑4 levels were higher in RR‑MS patients with mild disability compared to those with moderate and severe disability (P=0.0375). TNF‑α and IL‑10 levels were higher in RR‑MS patients with inactive disease compared with those with active disease. IL‑17 levels showed a trend towards being higher in RR‑MS patients with inactive disease compared to those with active disease (P=0.0631). Low TNF‑α and high IFN‑γ levels were independently associated with RR‑MS (P=0.0078 and 0.0056, respectively) and also with the activity of the disease (P=0.0348 and 0.0133, respectively). Results indicated that RR‑MS patients, even in the remission clinical phase, exhibit a complex system of inflammatory and anti‑inflammatory cytokines that may interact to modulate the progression and activity of the disease.

Cellular sources of dysregulated cytokines in relapsing-remitting multiple sclerosis

Background

Numerous cytokines are implicated in the immunopathogenesis of multiple sclerosis (MS), but studies are often limited to whole blood (WB) or peripheral blood mononuclear cells (PBMCs), thereby omitting important information about the cellular origin of the cytokines. Knowledge about the relation between blood and cerebrospinal fluid (CSF) cell expression of cytokines and the cellular source of CSF cytokines is even more scarce.

Methods

We studied gene expression of a broad panel of cytokines in WB from relapsing-remitting multiple sclerosis (RRMS) patients in remission and healthy controls (HCs). Subsequently we determined the gene expression of the dysregulated cytokines in isolated PBMC subsets (CD4⁺, CD8⁺T-cells, NK-cells, B-cells, monocytes and dendritic cells) from RRMS patients and HCs and in CSF-cells from RRMS patients in clinical relapse and non-inflammatory neurological controls (NIND).

Results

RRMS patients had increased expression of IFN-gamma (IFNG), interleukin (IL) 1-beta (IL1B), IL7, IL10, IL12A, IL15, IL23, IL27, lymphotoxin-alpha (LTA) and lymphotoxin-beta (LTB) in WB. In PBMC subsets the main sources of pro-inflammatory cytokines were T- and B-cells, whereas monocytes were the most prominent source of immunoregulatory cytokines. In CSF-cells, RRMS patients had increased expression of IFNG and CD19 and decreased expression of IL10 and CD14 compared to NINDs. CD19 expression correlated with expression of IFNG, IL7, IL12A, IL15 and LTA whereas CD14 expression correlated with IL10 expression.

Conclusions

Using a systematic approach, we show that expression of pro-inflammatory cytokines in peripheral blood primarily originates from T- and B-cells, with an important exception of IFNG which is most strongly expressed by NK-cells. In CSF-cell studies, B-cells appear to be enriched in RRMS and associated with expression of pro-inflammatory cytokines; contrarily, monocytes are relatively scarce in CSF from RRMS patients and are associated with IL10 expression. Thus, our findings suggest a pathogenetic role of B-cells and an immunoregulatory role of monocytes in RRMS.

The CD4+ T-cell subset lacking expression of the CD28 costimulatory molecule is expanded and shows a higher activation state in multiple sclerosis

Multiple sclerosis (MS) is a chronic debilitating disease, in which T-cells are considered to play a pivotal role. CD28 is the quintessential costimulatory molecule on T-cells and its expression declines progressively with repeated stimulations, leading to the generation of CD28(-) T-cells. Our aim was to examine whether CD4(+)CD28(-) T-cells were enriched in MS patients, and characterize the phenotype of this subset in MS patients and healthy controls (HC). All these changes could provide these CD4(+)CD28(-) T-cell characteristics that might be involved in the pathogenesis of MS, turning this T-cell subset into a potential target for future therapeutic strategies.

Influence of histocompatibility genes on disease susceptibility and treatment response in patients with relapsing-remitting multiple sclerosis treated with interferon β-1a

Multiple sclerosis (MS) is the most common, non-traumatic cause of neurological disability in young adults. The aim of this study was to investigate the influence of HLA class II alleles DRB1* and DQB1* on susceptibility to relapsing-remitting (RR) MS and response to interferon (IFN) β-1a treatment. A prospective observational study was conducted. Seventeen patients with clinically definite RRMS, attending a tertiary referral center for multiple sclerosis in Israel and receiving treatment with subcutaneous IFN β-1a, 22 mcg three times weekly were recruited between December 1998 and February 2000 and observed for 12 months. HLA genotyping was performed and clinical characteristics (relapse rate and disability progression) assessed at baseline and after 12 months. HLA data for a healthy control group were also used for comparison. HLA and the success of treatment with IFN β-1a in this group of RRMS patients were assessed. The frequency of DRB1*03 was six times higher in patients treated with IFN β-1a than in the healthy control group (n=100): 29% (5/17) versus 5% (5/100), respectively. Additionally, DQB1*03 and DQB1*02 were present in 82% (14/17) and 41% (7/17) of RRMS patients, but in only 33% (33/100) and 18% (18/100) of control patients, respectively. A better response to IFN β-1a treatment was seen in patients carrying these alleles than in patients without these alleles. Our results indicated that DRB1*03, DQB1*03 and DQB1*02 alleles may contribute to MS susceptibility and IFN β-1a responsiveness, and warrant further verification in a larger population.

Abnormal Tr1 differentiation in multiple sclerosis

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS). In the recent years, accumulating evidence has supported an immunosuppressive role for regulatory T cells (Tregs). Most studies in the context of autoimmunity have focused on the defects of the CD4+CD25 high Tregs. However, we recently demonstrated an altered function of Tr1 Treg cells in MS, characterized by a lack of IL-10 secretion. Therefore, several major regulatory T cell defects are involved in human autoimmune disease. Hence, the induction of Tregs or the stimulation of Treg activity may be beneficial for the treatment of such diseases.

Immunology of multiple sclerosis

Multiple sclerosis (MS) develops in young adults with a complex predisposing genetic trait and probably requires an inciting environmental insult such as a viral infection to trigger the disease. The activation of CD4+ autoreactive T cells and their differentiation into a Th1 phenotype are a crucial events in the initial steps, and these cells are probably also important players in the long-term evolution of the disease. Damage of the target tissue, the central nervous system, is, however, most likely mediated by other components of the immune system, such as antibodies, complement, CD8+ T cells, and factors produced by innate immune cells. Perturbations in immunomodulatory networks that include Th2 cells, regulatory CD4+ T cells, NK cells, and others may in part be responsible for the relapsing-remitting or chronic progressive nature of the disease. However, an important paradigmatic shift in the study of MS has occurred in the past decade. It is now clear that MS is not just a disease of the immune system, but that factors contributed by the central nervous system are equally important and must be considered in the future.

Generation and Regulation of Human Th1-Biased Immune Responses In Vivo: A Critical Role for IL-4 and IL-10

Tissue damage in many human autoimmune diseases is mediated by activated autoantigen-specific Th1 cells. Delineation of the regulatory mechanisms controlling a Th1-biased human immune reaction and its pathologic potential is, therefore, a critical step in the understanding of autoimmune diseases. In this study, we introduce a novel means to investigate human Th1-biased immune responses in vivo. Intraperitoneal injection of human mononuclear cells into immunodeficient mice generates a xenogeneic Th1-biased human immune response characterized by systemic inflammation and leukocytic infiltrates with a granuloma-like architecture in the liver, and the perigastrointestinal and perirenal fatty tissue. Th1 cell activation was dependent on the presence of APCs and could be blocked by cyclosporine. Importantly, neutralization of endogenously produced IL-4 and IL-10 markedly exaggerated the immune response, whereas exogenous IL-4 and IL-10 inhibited systemic Th1 immunity. Thus, the model described in this paper presents a useful means to analyze the regulation of human immune reactions in an in vivo situation. The results suggest that both IL-4 and IL-10 contribute to controlling the development of a human Th1-biased immune reaction.

The immunomodulatory properties of in vitro immunoglobulins are dose-dependent

OBJECTIVES

The mechanism by which intravenous immunoglobulins (immunoglobulin G, IgG) exert their beneficial effect on multiple sclerosis (MS) is unknown. Furthermore, there is uncertainty about the optimal dosage of IgG. Therefore, we investigated the influence of different IgG dosages on cytokine production in MS.

MATERIALS AND METHODS

Twenty-five MS patients and 15 healthy controls were enrolled. We measured the production of interferon gamma (IFN-gamma), tumour necrosis factor alpha (TNF) and interleukin 10 (IL-10) in peripheral blood lymphocytes by flowcytometry after stimulation without and with IgG in different doses (1, 5 and 10 mg/ml).

RESULTS

IFN-gamma and TNF were decreased significantly (P = 0.001) in the untreated and interferon beta (IFN-beta) treated patients after stimulation with IgG. In contrast, IL-10 production was significantly enhanced (P = 0.001) at least in the untreated patient group. The reduction of the pro-inflammatory cytokines IFN-gamma and TNF after stimulation with different IgG doses was clearly dose-dependent in all groups.

CONCLUSION

Besides a suppression of the pro-inflammatory cytokines IFN-gamma and TNF, IgG enhances the anti-inflammatory cytokine IL-10. This effect is dose-dependent, speaking in favour of higher IgG doses in the treatment of MS.

In-situ detection of both inflammatory and anti-inflammatory cytokines in resting peripheral blood mononuclear cells during pregnancy

INTRODUCTION

Local and possibly systemic curtailment of the maternal immune response is important for a successful pregnancy. Although the local milieu at the utero-placental interface is likely to harbor the most prominent alterations, it is suggested, at least in mice, that systemic immunity is also tolerized during pregnancy. In the present study, we investigated mRNA expression of the key immunomodulatory cytokines; interleukin (IL)-4, IL-10, tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma during normal pregnancy.

MATERIAL AND METHODS

In-situ hybridization (ISH) of cytokine mRNA in resting peripheral blood mononuclear cells (PBMCs) was used to detect the number of cells spontaneously expressing cytokines. Eleven women with normal gestations were followed during pregnancy as well as 8 weeks postpartum, and compared with 10 non-pregnant healthy controls.

RESULTS

The numbers of IFN-gamma and IL-4 mRNA expressing cells were found to be significantly increased during pregnancy and postpartum compared with non-pregnant controls. Pregnant women and non-pregnant controls did not differ in their expression of TNF-alpha and IL-10.

CONCLUSION

Our studies demonstrated increased numbers of both IFN-gamma and IL-4 mRNA expressing cells in blood suggesting that systemic immunomodulation, albeit partial, takes place during normal pregnancy. It is proposed that enhanced IL-4 expression, possibly in concert with other elevated anti-inflammatory immunomodulatory cytokines, curtail the potentially hazardous effects of IFN-gamma on systemic immunity during pregnancy.

Cytokines in multiple sclerosis: methodological aspects and pathogenic implications

Multiple sclerosis (MS) is one of the leading causes of disability among young adults of Caucasian origin. One hundred and fifty years after the first description of the disease, the cause of MS remains unknown. Ironically, the few hypotheses concerning MS pathogenesis that are valid today were first proposed over a hundred years ago. However, equipped with the advanced technology of molecular biology and imaging systems, we are at present progressively uncovering dues to understanding the pathogenesis of the disease. It is dearly evident that aberrant immune responses occur in MS, and it is likely that the spectrum of cytokines produced decisively influences disease outcome. The detrimental consequences of IFN-gamma and the beneficial effects of IFN-beta treatment in MS support this hypothesis. However, there are still major gaps in our knowledge of the involvement of cytokines in MS. Numerous studies have addressed the question of cytokine levels in MS, often with conflicting results; elevated, normal and decreased levels of almost all cytokines have been reported. This scenario most probably reflects methodological dilemmas as well as the complex biology of cytokines. Here we focus on possible reasons for the discrepancies of results reported on cytokines in MS and summarize findings obtained in particular by the application of enzyme-linked immunospot (ELISPOT) assays to cytokine studies in MS.

Cellular localization and expression patterns of interleukin-10, interleukin-4, and their receptors in multiple sclerosis lesions

Cytokines have been shown to play a crucial role in the pathogenesis of multiple sclerosis (MS). However, still limited data are available on the expression of anti-inflammatory cytokines within the central nervous system (CNS) during MS lesion development. Therefore, we have examined the expression of the anti-inflammatory cytokines, interleukin-10 (IL-10) and IL-4, and their specific receptors, IL-10R and IL-4R, in postmortem human brain tissue obtained from MS patients. Specific patterns of protein localization and expression for both proteins could be observed within active and chronic MS lesions. Strongest IL-10 immunoreactivity was observed in reactive astrocytes within active demyelinating lesions and the hypercellular rim of chronic active MS lesions. Moreover, perivascular macrophages were immunoreactive for IL-10 in (chronic) active MS lesions. Most intense IL-4 immunoreactivity was detected in reactive fibrillary astrocytes within the hypocellular regions of chronic active and chronic inactive MS lesions. Strong immunoreactivity for IL-10R and IL-4R was detected on macrophages in both parenchymal and perivascular areas and on reactive astrocytes in active and chronic MS lesions. Our results indicate that IL-10 and IL-4 have an active role in CNS immune responses. The specific patterns of protein localization and protein expression for both IL-10 and IL-4 in MS lesions at different stages of development suggest that these anti-inflammatory cytokines and their receptors participate in processes leading to the formation of chronic MS lesions.

Randomized study of antibodies to IFN-gamma and TNF-alpha in secondary progressive multiple sclerosis

Studies of cytokines in multiple sclerosis (MS) have shown that immune mechanisms connected with disturbance of the synthesis of cytokines probably play critical roles in the initiation and prolongation of MS. In a double-blind, placebo-controlled trial, 45 patients with active secondary progressive MS were randomized to three groups of 15 patients, each receiving a short course of antibodies to IFN-gamma, to tumor necrosis factor (TNF)-alpha, or a placebo. After 12 months with analysis of disability (Expanded Disability Status Scale scores), accompanied by interval determinations of lymphocyte subpopulations, cytokine production levels, MRI, and evoked potentials, it was found that only patients who received antibodies to IFN-gamma showed statistically significant improvement compared to the placebo group--a significant increase in the number of patients without confirmed disability progression. This was supported by MRI data (a decrease in the number of active lesions) and systemic changes in cytokine status (a decrease in IL-1beta, TNF-alpha, and IFN-gamma concentrations in supernatants of actvated blood cells of these MS patients and an increase in TGF-beta production). Neutralization of IFN-gamma could be a new approach to treating secondary progressive MS. Long-term administration of humanized monoclonal antibodies to IFN-gamma and simultaneous use of antibodies to IFN-gamma together with IFN-beta products are planned.

Interleukin-10 and the interleukin-10 receptor

Interleukin-10 (IL-10), first recognized for its ability to inhibit activation and effector function of T cells, monocytes, and macrophages, is a multifunctional cytokine with diverse effects on most hemopoietic cell types. The principal routine function of IL-10 appears to be to limit and ultimately terminate inflammatory responses. In addition to these activities, IL-10 regulates growth and/or differentiation of B cells, NK cells, cytotoxic and helper T cells, mast cells, granulocytes, dendritic cells, keratinocytes, and endothelial cells. IL-10 plays a key role in differentiation and function of a newly appreciated type of T cell, the T regulatory cell, which may figure prominently in control of immune responses and tolerance in vivo. Uniquely among hemopoietic cytokines, IL-10 has closely related homologs in several virus genomes, which testify to its crucial role in regulating immune and inflammatory responses. This review highlights findings that have advanced our understanding of IL-10 and its receptor, as well as its in vivo function in health and disease.

Interleukin-10 and the Interleukin-10 Receptor

Interleukin-10 (IL-10), first recognized for its ability to inhibit activation and effector function of T cells, monocytes, and macrophages, is a multifunctional cytokine with diverse effects on most hemopoietic cell types. The principal routine function of IL-10 appears to be to limit and ultimately terminate inflammatory responses. In addition to these activities, IL-10 regulates growth and/or differentiation of B cells, NK cells, cytotoxic and helper T cells, mast cells, granulocytes, dendritic cells, keratinocytes, and endothelial cells. IL-10 plays a key role in differentiation and function of a newly appreciated type of T cell, the T regulatory cell, which may figure prominently in control of immune responses and tolerance in vivo. Uniquely among hemopoietic cytokines, IL-10 has closely related homologs in several virus genomes, which testify to its crucial role in regulating immune and inflammatory responses. This review highlights findings that have advanced our understanding of IL-10 and its receptor, as well as its in vivo function in health and disease.

Defective regulation of IFNgamma and IL-12 by endogenous IL-10 in progressive MS

BACKGROUND

MS is a chronic inflammatory disease of the CNS postulated to be a Th1 type cell-mediated autoimmune disease. There is increased interferon-gamma (IFNgamma) secretion in MS, and IFNgamma administration induces exacerbations of disease. IFNgamma expression is closely regulated by a number of cytokines produced by different cells of the immune system. Interleukin-12 (IL-12) is a major factor leading to Th1-type responses, including IFNgamma secretion, and there is increased secretion of IL-12 in MS. IL-10 is a potent inhibitor of both IL-12 and IFNgamma expression.

METHODS

The authors investigated cytokine production and proliferative responses of peripheral blood mononuclear cells stimulated with soluble anti-CD3 in healthy controls and patients with stable relapsing-remitting MS or progressive MS.

RESULTS

The authors found that T cell receptor-mediated IFNgamma and IL-10 secretion were increased in progressive MS, whereas IL-4 and IL-2 secretion and lymphocyte proliferative responses were normal. Anti-IL-12 antibody suppressed raised IFNgamma in progressive MS but did not affect raised IL-10. In addition, neutralization of endogenous IL-10 upregulated IFNgamma in controls but not progressive MS. IL-10 was produced by CD4+ cells whereas IFNgamma was produced by both CD4+ and CD8+ cells. There were no differences in IL-10 receptor expression in MS patients.

CONCLUSIONS

These abnormalities in IL-10 regulation were not seen in the relapsing-remitting form of MS. Thus, the defect in regulation of both IL-12 and IFNgamma production by endogenous IL-10 in progressive MS could be an important factor involved in the transition of MS from the relapsing to the progressive stage and has implications for treating MS patients with exogenous IL-10.

Multiple sclerosis is associated with an imbalance between tumour necrosis factor-alpha (TNF-alpha)- and IL-10-secreting blood cells that is corrected by interferon-beta (IFN-beta) treatment

The up-regulated B cell responses detectable in cerebrospinal fluid (CSF) and the augmented myelin antigen-specific T cell responses observed in the CSF as well as systematically in patients with multiple sclerosis (MS) suggest the involvement of cytokines in disease development and perpetuation. Here we report on the parallel involvement of TNF-alpha, IL-6, IFN-gamma and IL-10 in MS and controls, using enzyme-linked immunospot (ELISPOT) assays to detect and enumerate cytokine-secreting mononuclear cells (MNC) prepared from blood and, for IL-6 and IL-10, from CSF without in vitro stimulation. MS is associated with elevated levels of TNF-alpha-secreting blood MNC when compared with levels in groups of control patients with myasthenia gravis (MG) and other neurological diseases (OND) or healthy subjects. This elevation was confined to patients with untreated MS and not present in those examined during ongoing treatment with IFN-beta. Untreated patients with MS had lower numbers of IL-10-secreting blood MNC compared with the three control groups. In patients undergoing treatment with IFN-beta, numbers of IL-10-secreting cells were in the same range as in controls. Normalization of TNF-alpha from elevated, and of IL-10 from decreased levels could be one reason for the beneficial effects of IFN-beta in MS, although it remains to be shown whether these changes reflect phenomena primarily involved in MS pathogenesis or secondary changes. In CSF, levels of IL-10-secreting cells were higher than in blood in both MS and OND, with no difference between these groups. Systemic aberrations of IL-6 and IFN-gamma and of IL-6 in CSF in MS versus controls were only minor, irrespective of treatment with IFN-beta.

Changes in plasma cytokines induced by interferon-beta1a treatment in patients with multiple sclerosis

It has been postulated that the efficacy of interferon-beta1a in multiple sclerosis may be due to the induction of type 2 cytokines. In this report we demonstrate that after 3 months of therapy, there is no sustained alteration in the plasma levels of type 1 (IL-12, IL-1beta and TNF-alpha) or type 2 (IL-6, IL-10) cytokines, but rather repeated induction of both with each injection. Little alteration is seen in the profile of cytokines induced with time, despite a decline in side effects. This suggests that IFN-beta1a causes repeated transient modulation of cytokine expression, but no sustained deviation in the type 1/type 2 balance.

Cytokine analysis in multiple sclerosis by competitive RT - PCR: A decreased expression of IL-10 and an increased expression of TNF-alpha in chronic progression

Multiple sclerosis (MS) is an inflammatory, demyelinating disease that is specific to the central nervous system. Cytokines are thought to be key mediators of the autoimmune attack against central nervous system myelin in MS. To investigate the involvement of cytokines in MS, the mRNA levels of interferon gamma (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), interleukin-4 (IL-4) and interleukin-10 (IL-10) in peripheral blood mononuclear cells without stimulation in vitro were quantified by a competitive reverse transcription polymerase chain reaction technique. The level of IL-10 specific mRNA was significantly decreased in 47 MS patients compared with 42 healthy controls (P<0.0001). TNF-alpha was significantly increased in MS patients compared with healthy controls (P=0.014), especially in the patients with chronic progressive MS (P=0.0003). Thus we conclude that there are significant in vivo alterations in cytokine gene expression in the periphery in MS.

Partial IL-10 Inhibition of the Cell-Mediated Immune Response in Chronic Beryllium Disease

Chronic beryllium disease (CBD) provides a human disorder in which to study the delayed type IV hypersensitivity response to persistent Ag that leads to noncaseating pulmonary granuloma formation. We hypothesized that, in CBD, failure of IL-10 to modulate the beryllium-specific, cell-mediated immune response would result in persistent, maximal cytokine production and T lymphocyte proliferation, thus contributing to the development of granulomatous lung disease. To test this hypothesis, we used bronchoalveolar lavage cells from control and CBD subjects to evaluate the beryllium salt-specific production of endogenous IL-10 and the effects of exogenous human rIL-10 (rhIL-10) on HLA expression, on the production of IL-2, IFN-γ, and TNF-α, and on T lymphocyte proliferation. Our data demonstrate that beryllium-stimulated bronchoalveolar lavage cells produce IL-10, and the neutralization of endogenous IL-10 does not increase significantly cytokine production, HLA expression, or T lymphocyte proliferation. Second, the addition of excess exogenous rhIL-10 partially inhibited the beryllium-stimulated production of IL-2, IFN-γ, and TNF-α; however, we measured no change in T lymphocyte proliferation or in the percentage of alveolar macrophages expressing HLA-DP. Interestingly, beryllium salts interfered with an IL-10-stimulated decrease in the percentage of alveolar macrophages expressing HLA-DR. We conclude that, in the CBD-derived, beryllium-stimulated cell-mediated immune response, low levels of endogenous IL-10 have no appreciable effect; exogenous rhIL-10 has a limited effect on cytokine production and no effect on T lymphocyte proliferation or HLA expression.

Multiple sclerosis is associated with high levels of circulating dendritic cells secreting pro-inflammatory cytokines

Recent evidence emphasises a pivotal role for dendritic cells (DC) in the control of immunity by priming and tolerising T cells. DC capture and process antigens, express co-stimulatory molecules, migrate to lymphoid organs and secrete cytokines to initiate immune responses. In multiple sclerosis (MS), autoreactive T cells are proposed to play a pathogenic role by secreting pro-inflammatory cytokines, but studies on DC are lacking. To evaluate the involvement of DC in patients with MS, a modified procedure was used to prepare DC from blood of patients with MS and healthy subjects. DC were found to be potent stimulators of T cells in allogeneic and, to a lesser extent, in autologous mixed leukocyte reaction (MLR). Enzyme-linked immunospot (ELISPOT) assays were adopted to determine levels of IFN-gamma, TNF-alpha, IL-6 and IL-10 secreting DC vs. mononuclear cells (MNC). Proportionally more DC than MNC secreted IFN-gamma and IL-10 in both MS and healthy subjects. Patients with MS had higher levels of IFN-gamma, TNF-alpha and IL-6 secreting DC than healthy subjects. The differences for IFN-gamma and TNF-alpha secreting cells were confined to the subgroup of untreated MS patients and not observed in the subgroup examined during ongoing treatment with IFN-beta. Circulating DC secreting pro-inflammatory cytokines may represent another focus for the study of both immuno-pathogenesis and therapeutic interventions in MS.

Interferon beta-1b treatment modulates TNFalpha and IFNgamma spontaneous gene expression in MS

BACKGROUND

Interferon beta (IFNbeta) lessens the overall frequency of acute attacks in patients with the relapsing-remitting form of multiple sclerosis (RRMS). IFNbeta may act by decreasing the synthesis of inflammatory cytokines.

OBJECTIVES

To determine whether IFNbeta-1b treatment had an initial and sustained effect on the in vivo synthesis and secretion of tumor necrosis factor alpha (TNFalpha) and IFNgamma.

METHODS

A highly sensitive reverse-transcriptase PCR technique was used to measure baseline levels of mRNA in freshly isolated cells from patients before therapy and at 3, 6, and 12 months of treatment. Also, protein concentration was measured in serum and in culture supernatants from mitogen-stimulated cells. The authors studied 16 patients, of whom 11 did not have clinical exacerbations, whereas 5 had one clinical relapse each during the study.

RESULTS

Mean values of TNFalpha mRNA levels in the 11 stable patients decreased significantly at 3 and 6 months of treatment in comparison with initial data. After 6 months of therapy, IFNbeta-1b downmodulated TNFalpha transcripts in the 5 patients who experienced relapse. In this group of patients, TNFalpha levels rose sharply to reach pretreated values at 1 year of IFNbeta-1b treatment. At the beginning of therapy, 6 patients had high concentrations of serum TNFalpha, which decreased to normal values following IFNbeta-1b therapy. IFNgamma mRNA expression also diminished after 6 and 12 months of IFNbeta-1b therapy in the group of stable patients, whereas nonrelevant variations were observed in patients who had one relapse. Initially, patients' peripheral mononuclear cells secreted diminished amounts of TNFalpha and IFNgamma on PHA + PMA mitogen stimulation in comparison with normal control subjects. After 1 year of therapy, IFNbeta-1b restored the normal production of TNFalpha, whereas therapy did not restore IFNgamma secretion to control values.

CONCLUSION

IFNbeta-1b decreases the spontaneous expression of two proinflammatory cytokines.

Decreased interleukin-10 and increased interleukin-12p40 mRNA are associated with disease activity and characterize different disease stages in multiple sclerosis

It has been shown that proinflammatory and antiinflammatory cytokines correlate with disease activity in multiple sclerosis (MS). To establish whether such correlations depend on the disease stage, we assessed in a longitudinal fashion the expression of interleukin (IL)-12 (p40 and p35), tumor necrosis factor-alpha, interferon-gamma, and IL-10 mRNA by competitive polymerase chain reaction in unstimulated peripheral blood mononuclear cells of relapsing-remitting (RR) and secondary progressive (SP) MS patients, in relation to monthly clinical and magnetic resonance imaging monitoring. MS patients had increased levels of IL-12p40 and decreased levels of IL-10 mRNA compared with controls; this difference was most pronounced in SP patients. Both RR and SP patients had increased levels of IL-12p40 mRNA compared with controls during the development of active lesions. Moreover, in RR MS an increase was found before relapse. IL-12p35 mRNA was decreased in both groups, and in relation to disease activity it showed a pattern different from IL-12p40 mRNA. In RR MS, IL-10 mRNA was low 4 weeks before magnetic resonance imaging activity and 6 weeks before relapse; a significant increase to normal levels was noted when active lesions became apparent. In contrast, SP patients showed low IL-10 mRNA levels constitutively, suggesting that IL-10 plays an important role in the control of disease progression.

Interleukin-17 mRNA expression in blood and CSF mononuclear cells is augmented in multiple sclerosis

Myelin-directed autoimmunity is considered to play a key role in the pathogenesis of multiple sclerosis (MS). Increased production of both pro- and anti-inflammatory cytokines is a common finding in MS. Interleukin-17 (IL-17) is a recently described cytokine produced in humans almost exclusively by activated memory T cells, which can induce the production of proinflammatory cytokines and chemokines from parenchymal cells and macrophages. In situ hybridisation with synthetic oligonucleotide probes was adopted to detect and enumerate IL-17 mRNA expressing mononuclear cells (MNC) in blood and cerebrospinal fluid (CSF) from patients with MS and control individuals. Numbers of IL-17 mRNA expressing blood MNC were higher in patients with MS and acute aseptic meningoencephalitis (AM) compared to healthy individuals. Higher numbers of IL-17 mRNA expressing blood MNC were detected in MS patients examined during clinical exacerbation compared to remission. Patients with MS had higher numbers of IL-17 mRNA expressing MNC in CSF compared to blood. This increase in numbers of IL-17 mRNA expressing MNC in CSF was not observed in patients with AM. Our results thus demonstrate increased numbers of IL-17 mRNA expressing MNC in MS with higher numbers in CSF than blood, and with the highest numbers in blood during clinical exacerbations.

Markers in the promoter region of interleukin-10 (IL-10) gene in myasthenia gravis: implications of diverse effects of IL-10 in the pathogenesis of the disease

Interleukin-10 (IL-10) is an important pleiotropic cytokine with both anti-inflammatory and B lymphocyte stimulating functions. The expression of IL-10 is tightly controlled. A bi-allelic polymorphism and 2 CA repeat microsatellites located in the promoter region of IL-10 gene were analysed in Swedish myasthenia gravis (MG) patients and ethnically matched healthy individuals. The prevalence of a 'high secretor' phenotype of IL-10 (IL-10 1 G/G) was higher in IL-1beta TaqI polymorphism allele 2 positive healthy individuals ('high secretor' phenotype for IL-1beta) than in healthy individuals negative for this allele. No such balance was found in MG patients. In one of the microsatellites, IL10.R, allele 112 was associated with patients having normal thymic histology. No relation of IL10.R allele 112 to proinflammatory cytokine gene polymorphisms and serum IgG, IgM and autoantibodies against nicotinic acetylcholine receptor (nAchR-Ab) was found. In another microsatellite, IL10.G, allele 134 was associated with patients having higher level of nAchR-Ab in their circulation. Our results demonstrated novel genetic markers within IL-10 gene indicating different mechanisms for IL-10 involved in the disease.

Increased reactivity to myelin oligodendrocyte glycoprotein peptides and epitope mapping in HLA DR2(15)+ multiple sclerosis

Multiple sclerosis (MS) is a central nervous system-specific inflammatory and demyelinating disease where a myelin-directed autoimmune response is thought to be pathogenetically relevant. Myelin oligodendrocyte glycoprotein (MOG) is a surface-exposed minor myelin component that is a prime candidate autoantigen. We have investigated peripheral blood lymphocyte responses to synthetic 15-26 amino acids long overlapping MOG peptides in 20 MS patients and 14 healthy controls with the MS-associated HLA haplotype DR2(15). There were significantly increased responses, in terms of numbers of cells secreting IFN-gamma detected by Elispot in response to several MOG-derived peptides in the MS patients, but not the healthy controls. MOG peptide 63-87 evoked the strongest response, and the stimulatory property of this peptide was confirmed in additional DR2(15)+ MS patients where a peptide concentration-dependent proliferative response, which was inhibited by the addition of anti-HLA class II antibodies, was observed. This is the first work detailing putative immunodominant T cell epitopes of MOG in DR2(15)+ MS patients.

Linomide (roquinimex) affects the balance between pro- and anti-inflammatory cytokines in vitro in multiple sclerosis

OBJECTIVES

Multiple sclerosis (MS) is characterized by high levels of circulating mononuclear cells (MNC) that respond to myelin proteins like myelin basic protein (MBP) in vitro by expressing mRNA of both pro-inflammatory cytokines, e.g. interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha) and lymphotoxin (LT) that may make MS worse, and anti-inflammatory cytokines like IL-4, IL-10 and transforming growth factor-beta (TGF-beta) that may act beneficially. Substances that down-regulate cytokines such as TNF-alpha or promote IL-10 or TGF-beta can be anticipated to affect MS beneficially.

MATERIAL AND METHODS

In situ hybridization to detect and enumerate IFN-gamma, TNF-alpha, LT, IL-4, IL-10 and TGF-beta mRNA expressing blood MNC after stimulation with myelin basic protein (MBP), control antigens and without antigen in presence and absence of Linomide (roquinimex, LS-2616) was employed. In parallel, ELISPOT assay to detect MBP- and PHA-reactive IFN-gamma secreting blood MNC+/-Linomide was used.

RESULTS

Here we report that Linomide, a synthetic immunomodulator, at concentrations effective in vivo reduces the number of MBP-reactive TNF-alpha and increases MBP-reactive IL-10 and TGF-beta mRNA expressing MNC from MS patients' blood when analysed in vitro. Compared to dexamethasone, Linomide up-regulated levels of blood MNC expressing mRNA of TGF-beta after culture in presence of MBP.

CONCLUSIONS

Changes of cytokine balance towards a production of anti-inflammatory cytokines could be a desirable effect to be evaluated in future drug studies of Linomide-like substances. At present, Linomide is not evaluable in MS clinical trials due to side-effects.

Elevated serum levels of IFN-gamma, IL-4 and TNF-alpha/unelevated serum levels of IL-10 in patients with demyelinating diseases during the acute stage

We investigated IFN-gamma, IL-4, IL-10 and TNF-alpha in the sera of 42 patients with demyelinating diseases: multiple sclerosis (MS) (21), Guillain-Barré syndrome (GBS) (14), Miller-Fisher syndrome (MFS) (7) during the acute or active stage and 12 normal controls using an originally devised sensitive sandwich enzyme-linked immunosorbent assay (ELISA). We found elevated serum levels of IFN-gamma derived from T helper 1 (Th1) cells and of IL-4 derived from Th2 cells in MS, GBS and MFS. It has been reported in several studies that IL-4 production is increased in MS; however, there have been no reports of elevated serum IL-4 levels in MS. We here describe elevated serum levels of IL-4 in MS, GBS and MFS for the first time. Serum TNF-alpha levels were significantly elevated in patients with MS (p < 0.01). Serum TNF-alpha levels also tended to be elevated in patients with GBS and MFS, but not significantly elevated compared with those of controls. Serum IL-10 levels were not elevated significantly in these diseases, although several patients had higher levels of serum IL-10 than controls. These findings suggest that simultaneous activation of both Th1 and Th2 cells may occur during the acute stage, indicating systemic involvement of the immune system in patients with MS, GBS and MFS. Levels of serum IFN-gamma were two- to three-fold higher than those of serum IL-4 in all three demyelinating diseases. We may then conclude that Th1 response may be dominant in GBS and MFS during the acute stage.

Data on cytokine mRNA expression in CSF and peripheral blood mononuclear cells from MS patients as detected by PCR

Reverse transcription polymerase chain reaction (RT-PCR) was used to amplify the mRNA coding for different cytokines in peripheral blood mononuclear cells (PBMC) and cerebrospinal fluid (CSF) cells from 18 multiple sclerosis (MS) patients as compared with 21 other neurological patients. mRNA levels were quantitated by radioactive hybridization of the PCR products. Expression of tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma, and interleukin (IL)-10 mRNA was elevated in CSF cells of MS patients. In many MS patients, both proinflammatory and immunoregulatory cytokine messages were detected in the CSF compartment. Such immune reactivity of CSF cells, as opposed to PBMC, was not associated with higher clinical activity of the disease. Expression of the B7.1 accessory molecule mRNA was similarly investigated. In the CSF, it was detected only in some clinically active MS cases and in other inflammatory diseases.

Linkage and association analysis of genes encoding cytokines and myelin proteins in multiple sclerosis

Several genetic factors are likely to play a role in the etiology of multiple sclerosis (MS). We used a candidate gene strategy in a study of polymorphic markers within or close to genes encoding cytokines (interferon-gamma (IFN-gamma), interleukin-2 (IL-2), IL-4, IL-4 receptor (IL-4R), IL-10, transforming growth factor-beta1 and -beta2) and myelin proteins (2',3'-cyclic-nucleotide 3'-phosphohydrolase (CNP:ase), myelin associated glycoprotein, oligodendrocyte myelin glycoprotein, proteolipid protein) in 34 Swedish multiplex MS families and in 147 sporadic MS patients and 95 healthy controls. No evidence for linkage was observed in two-point linkage analysis. However, a slightly positive LOD score of 0.88 (theta = 0.01) for IFN-gamma was found. Affected pedigree member (APM) analysis indicated a possible linkage with TGF-beta2 (p = 0.008) and IL-4R (p = 0.043). None of the cytokine markers were associated with MS in case-control analysis. Our results suggest a possible importance of the TGF-beta2, IL-4R and IFN-gamma genes in MS.

Interleukin-12 and perforin mRNA expression is augmented in blood mononuclear cells in multiple sclerosis

Cytokines are suggested to orchestrate an abnormal immune response in multiple sclerosis (MS). The regulatory cytokine interleukin (IL)-12 induces T-helper (Th) cell switch to the Th1 type and the production by cytotoxic T cells of perforin, a cell lysis-inducing factor. It has been suggested that Th1-like cytokines may promote the development of MS, and the production of perforin to induce oligodendrocyte damage. In-situ hybridization with radiolabelled synthetic oligonucleotide probes was used to detect and enumerate mononuclear cells (MNC) expressing IL-12 and perforin mRNA in blood and cerebrospinal fluid (CSF) from patients with MS and controls. Plasma and CSF levels of IL-12 (p70) were evaluated by ELISA. Higher numbers of IL-12 and perforin mRNA-expressing MNC were registered in blood in MS and also in controls with aseptic meningoencephalitis (AM) compared to healthy subjects. There were a few patients with other non-inflammatory neurological diseases who also had high levels of IL-12 or perforin mRNA expressing blood MNC. A parallel elevation was observed for IL-12 (p70) concentrations in plasma. In the MS patients' CSF, there was a further augmentation of IL-12 mRNA expressing MNC. To evaluate autoantigen-induced IL-12 and perforin mRNA expression, blood MNC were cultivated +/- myelin basic protein (MBP), a candidate autoantigen in MS. Higher numbers of MBP-reactive IL-12 and perforin mRNA expressing blood MNC were detected in MS than controls. The augmentation of both IL-12 and perforin in MS might reflect ongoing inflammatory processes in MS and could represent targets for future treatments.

Glucocorticoids increase IL-10 expression in multiple sclerosis patients with acute relapse

High doses of glucocorticoids (GCs) are widely employed to treat acute attacks in relapsing-remitting multiple sclerosis (MS) patients. Their beneficial effects are partially due to their capacity to regulate the cytokine network. In the present work, we have examined the effect of GCs on the production of the immunosuppressor cytokine IL-10. Blood samples from MS patients suffering an acute relapse were obtained immediately before initiating therapy and after receiving a daily dose of 1 g intravenous methylprednisolone (MP) for four days. Levels of IL-10 mRNA in PBMC were semiquantified by RT-PCR, whereas protein concentration in serum and in cell culture supernatant was measured by ELISA. Our results show that 7 out of the 9 patients studied displayed increased IL-10 mRNA expression as well as higher serum IL-10 concentration following steroid treatment. In contrast, mRNA expression of two inflammatory cytokines, TNFalpha and IFNgamma, decreased following steroid therapy. In vitro experiments employing normal PBMC showed that methylprednisolone (MP) upregulated IL-10 expression as determined by measuring mRNA levels, flow cytometry of intracytoplasmic protein concentration, and the amount of secreted protein. Peak responses of secreted IL-10 by PBMC cultured cells treated with MP were obtained at 48 h. The effect was steroid-specific as IL-10 expression reversed to baseline levels in the presence of the glucocorticoid receptor antagonist RU486. Contrary to the effect of MP on the spontaneous expression of IL-10, this drug downregulated LPS-induced IL-10 synthesis. In fact, the concentration of IL-10 in LPS-induced IL-10 secretion from normal PBMC decreased upon addition of MP to cell cultures. Thus, it seems that MP exerts an opposite effect on the spontaneous and LPS-induced IL-10 production. Our studies indicate that GCs may control inflammatory responses by upregulating production of the immunosuppressor cytokine IL-10.

Corticosteroids induce expression of transforming-growth-factor-beta1 mRNA in peripheral blood mononuclear cells of patients with multiple sclerosis

The mechanisms by which corticosteroids act in the treatment of an acute relapse in multiple sclerosis (MS) are not completely known. We investigated the mRNA and protein expression of transforming-growth-factor-beta1 (TGFbeta1), a cytokine with anti-inflammatory and immunosuppressive potentials, in peripheral blood mononuclear cells (PBMC) and serum of 10 patients with an acute relapse of MS before, during and after the treatment with 500 mg prednisolone daily over 5 days. The expression of TGFbeta1-mRNA increased at day 3-5 and declined at day 8-10. Serum levels of TGFbeta1 demonstrated a comparable course. The present data suggest that corticosteroids induce the expression of TGFbeta1 in vivo. This is might be an other mechanism by which corticosteroids mediate immunosuppression.

The cytokine storm in multiple sclerosis

MS is associated with a cytokine storm characterized by the parallel upregulation of proinflammatory (IFN-gamma, TNF-alpha, and beta, and IL-12) and immune response-down-regulating (TGF-beta, IL-10) cytokines. Also IL-6 and the cytolytic molecule perforin are upregulated. Even when evaluated in individual MS patients over the disease course, no Th1/Th2 dichotomy is obvious but, instead, upregulation of Th1 + Th2 + Th3 cytokines simultaneously, probably reflecting the complex pathology of MS in lesion size, time and distribution in the individual patient. Few correlations have been observed between cytokines and clinical MS variables, though upregulation of TGF-beta seems to correlate with benign course and minor disability. Both pro- and antiinflammatory cytokines are also produced by microglia and astrocytes, constituting a CNS-cytokine network that interacts with the cytokine network of the immune system. This complexity is to be kept in mind when searching for cytokine abnormalities in MS.

Cytokine mRNA expression in CSF and peripheral blood mononuclear cells in multiple sclerosis: detection by RT-PCR without in vitro stimulation

We amplified the mRNA for cytokines in peripheral blood mononuclear cells (PBMC) and cerebrospinal fluid (CSF) cells from 18 multiple sclerosis (MS) patients and 21 other neurological patients, using reverse transcription polymerase chain reaction (RT-PCR). A radioactive hybridization of the amplified DNA allowed quantitation of mRNA levels. Expression of tumor necrosis factor (TNF)-alpha, interferon (IFN)-gamma and interleukin (IL)-10 mRNA was elevated in CSF cells of MS patients. IFN-gamma and IL-10 mRNA levels were higher in MS patients than in other inflammatory neurological diseases. In many MS patients, both proinflammatory and immunoregulatory cytokine messages were detected in the CSF compartment. Such immune reactivity in CSF, as opposed to the peripheral compartment, did not correlate with the clinical activity of the disease.

Cytokine secretion and nitric oxide production by mononuclear cells of patients with multiple sclerosis

Several experimental findings suggest a potential role of excessive nitric oxide (NO) production by macrophages, microglia and astrocytes in the pathogenesis of demyelinating lesions in MS. We assessed the production of nitrites by peripheral blood mononuclear cells (PBMCs) of 15 MS patients (10 F and 5 M) with the R-R form (EDSS: 1-3.0) and in 15 age-matched control subjects. 9 out of the 15 MS patients showed active lesions in MRI at the time of examination. 7 patients were also monitored at the onset, during and following a clinical relapse. Secretion of cytokines by PBMCs was assessed at the basal time and after 24 h of incubation with lipopolysaccharide (LPS). The production of nitrites in the supernatants of PBMCs stimulated and not stimulated with lipopolysaccharide was evaluated. The secretion of IL1 beta, IFN-gamma, TNF-alpha, IL-6 IL-10 and TGF-beta by PBMCs was detected using ELISA methods. The production of NO, both basal and stimulated, was significantly higher in the patients with active lesions than in those without active lesions (p < 0.01). No significant difference was evident between the basal and LPS-stimulated production of NO between control subjects and MS patients without active lesions. During relapses there was a significant increase in NO production by PBMCs compared to the clinical stable stage of the disease (p < 0.0001). This increase was significantly greater in the early stage of relapse than in the late stage (p < 0.04). A decline of NO levels was observed during recovery. Steroid treatment induced a significant decrease in the PBMC NO production of MS patients during exacerbations (p < 0.01). The levels of IL-1 beta, IFN-gamma and TNF-alpha are significantly higher in the supernatants of the PBMCs which produced greater amounts of NO (p < 0.02, p < 0.03, p < 0.01, respectively). On the other hand, NO levels were negatively related to IL-10 and TGF-beta production (R = -75, p < 0.0001 and R = -0.79, p < 0.0001, respectively). The increase production of NO by peripheral blood mononuclear cells demonstrated in our study to be associated with increased production of proinflammatory cytokines could therefore be considered to be a marker of mononuclear cell activation in the peripheral blood of MS patients and, indirectly, of disease activity. Its increased secretion during T cell and monocyte homing in the CNF could contribute to the damage to the blood-brain barrier and the subsequent cytokine-mediated cytotoxic effect to myelin and oligodendrocytes in the white matter of MS patients.

Cytokines and the pathogenesis of myasthenia gravis

Myasthenia gravis (MG) and its animal model experimental autoimmune myasthenia gravis (EAMG) are caused by autoantibodies against nicotinic acetylcholine receptor (AChR) in skeletal muscle. The production of anti-AChR antibodies is mediated by cytokines produced by CD4+ and CD8+ T helper (Th) cells. Emerging investigations of the roles of cytokines in MG and EAMG have revealed that the Th2 cell related cytokine interleukin 4 (IL-4), an efficient growth promoter for B-cell proliferation and differentiation, is important for anti-AChR antibody production. IL-6 and IL-10 have similar effects. The Th1 cytokine IFN-gamma is important in inducing B-cell maturation and in helping anti-AChR antibody production and, thereby, for induction of clinical signs and symptoms. Results from studies of time kinetics of cytokines imply that IFN-gamma is more agile at the onset of EAMG, probably being one of the initiating factors in the induction of the disease, and IL-4 may be mainly responsible for disease progression and persistance. Even though other Th1 cytokines like IL-2, tumor necrosis factor alpha (TNF-alpha), and TNF-beta as well as the cytolytic compound perforin do not directly play a role in T-cell-mediated help for anti-AChR antibody production, they are actually involved in the development of both EAMG and MG, probably by acting in concert with other cytokines within the cytokine network. In contrast, transforming growth factor beta (TGF-beta) exerts immunosuppressive effects which include the down-regulation of both Th1 and Th2 cytokines in MG as well as EAMG. Suppressive effects are also exerted by interferon alpha (IFN-alpha). Based on elucidation of the role of cytokines in EAMG and MG, treatments that up-modulate TGF-beta or IFN-alpha and/or suppress cytokines that help B-cell proliferation could be useful to improve the clinical outcome.

The pattern of production of cytokine mRNAs is markedly altered at the onset of multiple sclerosis

Using two independent PCR-based quantification techniques, we have determined the levels of IL1 beta, IL2, IL4, IL6, IL10, IFN gamma and TNF alpha mRNA in multiple sclerosis patients at the moment of diagnosis of the disease and prior to any immunosuppressive treatment. These patients exhibit markedly reduced IL2 and IL10 mRNA expression accompanied by decreased levels of TNF alpha mRNA. Our results add to the evidence that IL10 plays a role in multiple sclerosis and suggest that decreased production of this interleukin allows the proliferation of autoreactive T cells at the onset of the disease.

Detection of altered T helper 1 and T helper 2 cytokine production by peripheral blood mononuclear cells in patients with multiple sclerosis utilizing intracellular cytokine detection by flow cytometry and surface marker analysis

Production of T helper 1 and T helper 2 cytokines was investigated in peripheral blood mononuclear cells (PBMCs) from multiple sclerosis (MS) patients by a newly described technique, detection of intracellular cytokines by flow cytometry in conjunction with immunophenotype analysis. T-cell gamma interferon (IFN-gamma) production and interleukin 10 (IL-10) production were examined after PBMC activation with T-cell mitogens at 5 and 24 h, and monocyte spontaneous production of IL-10 and production after PBMC activation with lipopolysaccharide (LPS) for 24 h were also examined. The data indicate that MS patients have decreased percentages of T cells capable of secreting IFN-gama compared with healthy controls, and this change is detectable at 5 and 24 h. the patients displaying decreased T-cell production of IFN-gamma were essentially confined to a group being treated with the newly approved drug Betaseron (berlex Labs, Cedar Knolls, N.J.), a recombinant form of IFN-beta (rIFN-beta 1b). By gating of the entire lymphocyte population, analysis of IFN-gama production in T cells (CD3+ versus that in non-T cells (CD3+) was possible. The percentage of IFN-gamma-producing lymphocytes that was made up of T cells was essentially unchanged between the Betaseron-treated patients, non-Betaseron-treated patients, and controls, indicating that the suppression of IFN-gamma production displayed by betaseron-treated MS patients was a nonspecific suppression of all IFN-gamma-producing lymphocytes as opposed to a suppression of T-cell production only. The data seem to indicate that treatment of MS with Betaseron corresponds to an inhibition of the lymphocyte's ability to produce IFN-gamma. No changes were detected in T-cell production of IL-10 at either time point. We also observed that MS patients in general appear to have small percentages of peripheral blood monocytes spontaneously producing slight but detectable levels of IL-10. No difference was seen regarding monocyte production of IL-10 after PBMC activation with LPS between MS patients and controls. Both populations responded with high percentages of monocytes producing IL-10. The data seem to indicate that treatment of MS with Betaseron, known to decrease the exacerbation rate of relapsing-remitting MS, corresponds to a suppression of peripheral blood lymphocyte production of IFN-gamma. Monocyte production of IL-10 may also play a role in regulating the disease process.

Increased interleukin-6 mRNA expression in blood and cerebrospinal fluid mononuclear cells in multiple sclerosis

The increased intrathecal production of immunoglobulins within the cerebrospinal fluid (CSF) compartment commonly observed in multiple sclerosis (MS) implicates participation of B cell activating factors. One effect of the cytokine interleukin (IL)-6 is induction of immunoglobulin production by activated B cells. Employing in situ hybridization (ISH) with synthetic oligonucleotide probes, we measured numbers of IL-6 mRNA-expressing mononuclear cells (MNC) in blood and CSF from patients with MS, aseptic meningo-encephalitis (AM), and in blood from patients with other neurological diseases (OND) and healthy subjects. Numbers of IL-6 mRNA-expressing MNC were elevated in blood (mean frequency 1 per 33,000 MNC) and even further enriched in the CSF (1 per 10,000 MNC) of MS patients, and to a similar extent in AM patients' blood. Cultivation in the presence of myelin basic protein and proteolipid protein revealed strong augmentation of IL-6 mRNA-positive cells in MS but not in OND. The results suggest that IL-6 is one of several cytokines which are upregulated in MS, in particular locally in the CSF. A role of IL-6 in MS, whether disease- promoting or protective, remains unclear.

Alterations in peripheral blood mononuclear cell cytokine production in response to phytohemagglutinin in multiple sclerosis patients

Multiple sclerosis (MS) is an autoimmune demyelinating disorder of the central nervous system (CNS). The disease is characterized by inflammatory lesions in the white matter of the CNS, consisting of a specific immune response to the myelin sheath. We investigated peripheral blood mononuclear cell (PBMC) cytokine production by enzyme-linked immunosorbent assays of 21 MS patients and 19 age-matched normal controls in response to the T-cell mitogen phytohemagglutinin (PHA). Peripheral blood mononuclear cells were cultured in medium alone or in medium with 5 micrograms of PHA per ml for 48 h, and culture supernatants were collected for analysis. Cytokines selected for study were interleukin-10 (IL-10), gamma interferon (IFN-gamma), IL-2, and IL-4. All cytokine activities described were expressed as concentrations per 500,000 cells. We found that 48% (10 of 21) of the MS patients produced small but detectable levels of IL-10 in medium alone, compared with 26% (5 of 18) of the controls. We found that the MS patients produced significantly higher quantities of IL-10 protein than the controls in response to PHA (mean supernatant concentrations of IL-10 for patients and controls, 421 and 204 pg/ml, respectively [P < 0.05]). No significant differences were detected in the production of IL-2, IFN-gamma, and IL-4 between patients and controls in response to PHA, although patients appeared to display a trend toward decreased production of IFN-gamma.

Expression of IFN-gamma, IL-4, and TGF-beta in multiple sclerosis in relation to HLA-Dw2 phenotype and stage of disease

Multiple sclerosis (MS) is associated with upregulation of both proinflammatory (interferon-gamma, IFN-gamma) and immunosuppressive (transforming growth factor-beta, TGF-beta) cytokines. To examine a possible relation between the MS-related HLA haplotype Dw2 and cytokine profiles, we used in situ hybridization with labeled cDNA oligonucleotide probes to detect transcripts of the T helper type 1 (Th 1) cell related IFN-gamma, the Th2 cell related interleukin-4 (IL-4) and of TGF-beta in blood and cerebrospinal fluid (CSF) mononuclear cells from 62 patients with MS. Compared to patients with other neurological diseases and healthy controls, MS patients had elevated numbers of IFN-gamma, IL-4 and TGF-beta mRNA expressing cells in blood and further augmented in CSF. Although several HLA-Dw2-positive individuals showed very high numbers of cells expressing these cytokines, no significant difference was found in comparison with Dw2-negative patients. However, expression of IL-4 and TGF beta mRNA was significantly increased in patients with shorter duration and minor disability and, for IL-4, in patients still in the relapsing-remitting phase compared to patients with secondary chronic progressive MS. Surprisingly, these changes which favour a beneficial, disease-downregulating effect of IL-4 and TGF-beta in MS, were found to be confined to HLA-Dw2-positive patients. Our findings suggest that the HLA phenotype does not influence the overall level of immune reactivity in MS, but may distinguish subgroups characterized by particular cytokine expression patterns.