Multiple sclerosis: expression of CD1a and production of IL-12p70 and IFN-gamma by blood mononuclear cells in patients on combination therapy with IFN-beta and glatiramer acetate compared to monotherapy with IFN-beta

Current therapy of multiple sclerosis (MS) with interferon-beta (IFN-beta) or glatiramer acetate (GA) has modest effects on the course of MS. Both compounds affect several immune variables, like expression of cell surface molecules and cytokine levels. Here we compared untreated MS, therapy with IFN-beta alone and combined with GA, and healthy controls (HC), regarding expression on HLA-DR+ blood mononuclear cells (MNC) of CD1a that is a cell surface molecule with capacity to present glycolipids to T cells, and of CD80 and CD86 which are costimulatory molecules that activate Th1 and Th2 responses. Cytokine production by MNC was also measured. Flow cytometry and ELISA were used. Cross-sectional comparisons revealed that untreated MS patients had higher CD1a+ HLA-DR+ MNC and lower IL-10 production compared to patients treated with IFN-beta or IFN-beta+GA or HC. Untreated MS patients also had higher spontaneous IFN-gamma and IL-12p70 production compared to MS patients treated with IFN-beta+GA or HC, but not when compared to MS patients on monotherapy with IFN-beta. Low CD1a+ HLA-DR+ MNC and low spontaneous production of IL-12p70 and IFN-gamma were more pronounced in patients treated with IFN-beta+GA than with IFN-beta alone. In order to clarify whether these changes reflect disease activity or treatment effects, we performed a follow up study. Nineteen MS patients with disease progression, despite monotherapy with IFN-beta for more than one year; were re-examined after one to three and four to six months of treatment with IFN-beta+GA. This combination therapy was associated with normalization of CD1a+ HLA-DR+ MNC, IL-12p70 and IFN-gamma. It remains to be shown whether these immunological changes imply a clinical benefit. Follow up studies of immune variables versus clinical effects during combined therapy of MS with IFN-beta+GA are ongoing.     

Glatiramer acetate and IFN-beta act on dendritic cells in multiple sclerosis.

Glatiramer acetate (GA; Copolymer 1; Copaxone) and interferon-beta (IFN-beta) modulate the course of multiple sclerosis (MS), but probably by different mechanisms. GA, a mixture of synthetic peptides, is believed to act as an altered peptide ligand with inhibitory effects on autoreactive T cells and promoting Th2 cells. It is unknown whether GA affects dendritic cells (DCs), which, besides strong antigen presenting capacity, orchestrate Th1 and Th2 responses. IFN-beta inhibits IL-12 production by DCs over unknown mechanisms. This study was designed to investigate in vitro effects of GA and IFN-beta on the development and function of DCs from MS patients and healthy controls, and to explore their possible synergistic effects on DCs. DCs were generated from adherent blood mononuclear cells (MNCs). GA or IFN-beta or both, when added at initiation of DC cultures, rapidly promoted the development of adherent MNCs into floating, activated DCs as reflected by up-regulation of HLA-DR and CD86 expression. IFN-beta, but not GA, induced IL-3R expression on DCs. Compared to DCs from healthy controls, MS patients' DCs expressed higher levels of the myeloid DC marker CD1a and produced lower amounts of IL-10. GA reduced IL-12 production by DCs. IFN-beta also reduced IL-12, but increased IL-10 production by DCs from both MS patients and healthy controls. GA and IFN-beta synergistically suppressed CD1a and enhanced CD86 expression on MS DCs. These findings document novel mechanisms of action of GA and IFN-beta at the DC level in MS.     

Glatiramer acetate induces pro–apoptotic mechanisms involving Bcl–2, Bax and Cyt–c in peripheral lymphocytes from multiple sclerosis patients

Apoptotic deletion of autoreactive T-cells is defective in patients with multiple sclerosis (MS). Glatiramer acetate (GA) treatment seems to restore apoptosis of detrimental T-cells. We analyzed the mitochondria membrane pro- (Bax) and anti-apoptotic (Bcl- 2) and cytosolic pro-apoptotic (Cyt-c, APAF-1) proteins expression in peripheral lymphocytes from relapsing-remitting (RR) MS patients during GA treatment. Blood samples were collected from 8 healthy controls (HCs) and from 8 RR MS patients prior to and every three months during the 9 months of GA treatment. Peripheral blood mononuclear cells (PBMNCs) Bcl-2, Bax, Cyt-c and APAF-1 were quantified by western blot followed by densitometric scanning and Bax/Bcl-2, cytosolic Cyt-c/Bcl-2 and APAF-1/Bcl-2 ratios were calculated. T-cells were in vitro tested for oxygen consumption by a respirometric analysis. Bax/Bcl-2, cytosolic Cyt-c/Bcl-2 and APAF-1/Bcl-2 ratios in untreated MS patients were significantly (p < 0.05) lower than in HCs. Bax/Bcl-2 ratio increased (p = 0.03) and Cyt-c/Bcl-2 ratio showed a trend to increase during the 9 months of GA treatment in MS patients. A reduction of 58% and 59% in oxygen consumption by PBMNCs was evident after GA treatment in vitro or when GA treated patients' cells were compared with those from HCs, respectively. Our findings suggest that GA exerts a regulatory effect on peripheral T lymphocytes through pro-apoptosis mechanisms involving mitochondria and cytosolic proteins.     

Monocyte-derived dendritic cells in multiple sclerosis: the effect of bacterial infection

We investigated whether monocyte-derived dendritic cells (MDDCs) generated in vitro from bacteria-infected MS patients modified autoreactive T cells activation patterns. T cell clones (TCCs) stimulated with MDDCs from infected MS patients responded with maximal proliferation, inducing IL-12, IL-17 and IFN-gamma secretion, at concentrations significantly lower than after incubation with MDDCs isolated from uninfected individuals and bacterial meningitis (BM) patients. Moreover, infected MDDCs promoted TCCs survival, and secreted more IL-12, IL-18, and IL-23. Finally, MDDCs from infected MS subjects showed higher expression of myeloid differentiation factor 88 (MyD88), as well as of HLA-DR, CD1a, CD80, CD86, CD273, CD40, CD83 and CCR7 when compared to MDDCs from uninfected MS individuals, and BM patients. Thus, activation of the innate immune system by microbial products in MS patients affects the generation MDDCs and their ability to modify autoreactive T cell activation patterns, which may be linked to MS relapse induction during bacterial infections.     

Upregulation of TRAIL expression on human T lymphocytes by interferon beta and glatiramer acetate

We measured the in vivo and in vitro effects of interferon (IFN)beta and glatiramer acetate (GA) on the expression of the regulatory molecule, tumor necrosis factor related apoptosis inducing ligand (TRAIL), in patients with multiple sclerosis (MS). We confirmed the prior observation that TRAIL is enhanced on anti-CD3 activated T cells by the in vitro addition of IFNbeta. T cells from IFNbeta-treated patients stimulated with anti-CD3 only, had higher levels of TRAIL than untreated patients, suggesting that in vivo IFNbeta exposure has an effect on TRAIL expression in association with T cell activation. In vitro IFNbeta-induced TRAIL upregulation on anti-CD3 or phytohemagglutinin-activated T cells was comparable for IFNbeta-treated and non-treated MS patients and controls, indicating that IFN receptors were neither saturated nor down-regulated by current IFNbeta therapy. Although GA in vivo or in vitro did not induce TRAIL, the IFNbeta +GA combination in vitro enhanced TRAIL expression to higher levels than IFNbeta alone on CD4+ T cells obtained from MS patients, regardless of GA treatment status, and healthy donors, and on GA reactive T cell lines derived from GA-treated patients or controls. Whether any observed therapeutic effects of GA/IFNbeta combination therapy will correlate with TRAIL expression and function remains to be determined.     

Multiple sclerosis: deficient in vitro responses of blood mononuclear cells to IFN-β

IFN-beta may modify the clinical course of multiple sclerosis (MS) but is not curative, and there are also patients whose disease does not respond to IFN-beta as currently administered. Tests are warranted with a capacity to early discriminate responders from non-responders, thereby altering treatment option for the individual patient. In vitro effects of IFN-beta on expression of activation-associated cell surface markers and cytokine production need to be explored in this context. Here we report on the influence in vitro of IFN-beta on blood mononuclear cells (MNC) prepared from MS patients and healthy controls. MNC were subjected to short-term culture in the presence of IFN-beta at concentrations of 100 U/ml and 1000 U/ml. Expression of cell surface molecules CD40, CD69, CD80, CD86, CD95 and HLA-DR was measured by flow cytometry. IL-10 and IL-12 p40 production in culture supernatants was measured by ELISA. MNC exposed to IFN-beta in vitro enhanced expression of the co-stimulatory CD80, CD86, the early activation antigen CD69 and the cell death receptor CD95. Expression of CD40 and HLA-DR was not influenced. IFN-beta increased IL-10 but suppressed IL-12 p40 production. In vitro effects of IFN-beta on MNC were similar in MS patients and in healthy subjects, except that IFN-beta-induced augmentation of CD86 and CD69 expression was less pronounced in MS, in particular in untreated MS patients. Individual MS patients clearly responded differently to IFN-beta in vitro in comparison with the majority of patients in this cross-sectional study. In conclusion, anti-inflammatory effects of IFN-beta on blood MNC include augmentation of IL-10 production and suppression of IL-12 p40 production, which are accompanied by enhancement of CD69, CD80, CD86 and CD95 expression. The less pronounced IFN-beta-induced effects on CD86 and CD69 expression in MS vs controls might reflect a defect in immunoregulation in MS. Larger groups should be evaluated, and follow-up studies performed in MS patients before/during IFN-beta treatment in relation to clinical outcome measures to evaluate the usefulness of these markers for possible differentiation between responders and non-responders to IFN-beta treatment.     

Multiple sclerosis: modulation of apoptosis susceptibility by glatiramer acetate

OBJECTIVES: We investigated whether therapy of multiple sclerosis (MS) with glatiramer acetate (GA) involves the modulation of programmed cell death (apoptosis) in disease-relevant T-helper lymphocytes. MATERIAL AND METHODS: Blood was drawn from 15 relapsing-remitting MS patients both before (baseline) as well as 6, 12, and 18 weeks after GA therapy and from 15 healthy controls. Detection of apoptosis was performed in response to in vitro stimulation with GA, myelin basic protein or medium alone. RESULTS: T-helper lymphocytes from untreated MS patients displayed an overall increased apoptosis susceptibility in vitro, compared to controls. During subsequent GA therapy, apoptosis vulnerability of these T cells in MS patients significantly declined under the initial baseline before treatment, and was finally equal in treated patients and controls. GA itself had no direct apoptosis-modulatory properties in vitro. CONCLUSION: Our findings indicate that therapy of multiple sclerosis with glatiramer acetate presumably involves the compensation of altered apoptosis in T-helper lymphocytes.     

Effect of combined IFNbeta-1a and glatiramer acetate therapy on GA-specific T-cell responses in multiple sclerosis

The combined treatment with interferon beta (IFNbeta) and glatiramer acetate (GA) is of current interest in multiple sclerosis (MS). The therapeutic effect of GA in MS is believed to be mediated by GA-specific Th2 cells. IFNbeta has a significant anti-proliferative effect on GA-induced lymphoproliferation in vitro. Therefore, we examined the possibility that IFNbeta may interfere with the generation and phenotype of GA T-cell responses in MS patients receiving combined therapy. Sixty-six GA-specific T-cell lines (TCL) were generated ex vivo from five MS patients enrolled in an open-label dinical trial of combined IFNbeta/GA treatment. Controls included 83 pretreatment and 131 on-treatment GA-TCL from 11 MS patients treated with GA only, and five GA-TCL generated from four patients receiving IFNbeta-1a monotherapy. IFNgamma and IL-5 (markers of Th1 and Th2 responses, respectively) were assayed by ELISA in GA-TCL supematants. Th1/Th2 bias was defined by the IFNgamma/IL-5 level ratio ( >2 = Th1 bias, <0.5 = Th2 bias, and 0.5-2 = Th0 bias). The frequency with which GA-reactive TCL were generated was 37.0% for the patients in the combination trial compared to 33.3% in the patients receiving GA alone. The mean stimulation index of the GA-TCL was 8.41 (range 2-42) for the combination compared to a mean of 6.29 (range 2-37) for the GA-treated group--a nonsignificant difference. Mean GA-TCL IFNgamma production was significantly lower in all treatment groups compared to pretreatment IL-5 levels were enhanced in all treatment groups compared to pretreatment levels, but the change was not statistically significant. The Th1/Th0/Th2 distribution of GA-TCL was 7%/30%/63% for the GA+IFNbeta group, 8%/9%/83% for the GA group, compared to 48%/21%/31% pre-GA treatment. All five GA-TCL from the IFNbeta-1a monotherapy patients were Th2-biased. We conclude that IFNbeta-1a does not affect the generation of GA-reactive T cells in vivo. Although more Th0 G4-TCL occurred with combination therapy than with G4 treatment alone, both groups shared an overall Th2 bias. Therefore, we speculate that combined therapy is unlikely to reduce the efficacy of GA treatment in MS.     

Immunological study of IFNbeta-1a-treated and untreated multiple sclerosis patients: clarifying IFNbeta mechanisms and establishing specific dendritic cell immunotherapy

OBJECTIVES: A comparative immunological evaluation of multiple sclerosis (MS) patients receiving IFNbeta treatment and patients who are not receiving treatment may help clarify IFNbeta neurological mechanisms and lead the way to an effective dendritic cell (DC) immunotherapy. This type of study helps clarify the pathological function of T cells and DCs within the TH1/TH2/TH3 network as well as the specific interactions between TH1/TH2/TH3 cytokines implicated in MS pathological mechanisms and determine the best way of reestablishing the TH1/TH2/TH3 network equilibrium. METHODS: We studied network interactions between TH1/TH2/TH3 cytokine levels in serum and supernatants of whole blood and CD14+ monocyte-derived DCs in the remission phase of the disease and in correlation to the Expanded Disability Status Scale (EDSS). RESULTS: We found that TH1 dysregulation results in a disruption of the maturation and activation of dendritic and T cells, and a lack of T-regulating cells for the induction of self-tolerance; IFNbeta mechanisms restore regulation by reestablishing the network balance but fail to resolve the disease completely due to in vivo IL12p70 network interactions leading to the deletion of self-aggressive cells. CONCLUSIONS: Our results indicate that a specific DC immunotherapy could cure rather than treat MS. The best point to reestablish the normal physiological cycle is at the immature DC stage which can be done in vitro with treated peripheral blood CD14+ cells and used in vivo to stimulate the expansion of specific regulatory T cells.     

Dendritic cells in multiple sclerosis lesions: maturation stage, myelin uptake, and interaction with proliferating T cells

In multiple sclerosis (MS), dendritic cells (DCs) recruited to the central nervous system (CNS) are thought to be involved in the regulation of autoimmune responses directed against myelin antigens. To better understand the role of DCs in CNS inflammation, we performed a detailed immunohistochemical analysis of DC maturation markers and of DC relationship to CNS-infiltrating T cells in autopsy brain tissue of patients with MS. We also investigated the presence of DCs containing myelin debris in MS lesions. Myeloid DC subsets were identified using the following markers: CD1a for immature DCs; DC-SIGN for immature and mature DCs; and fascin, CD83, DC-LAMP, and CCR7 for mature DCs. The most common finding was the presence of cells expressing DC-SIGN and containing myelin components in the perivascular cuffs of early active and chronic (both active and inactive) MS lesions. Perivascular CD1a DCs were detected in active lesions in only one of 10 patients with MS who were examined. Although less numerous than DC-SIGN DCs, cells expressing mature DC markers were consistently detected in the inflamed meninges and perivascular cuffs of most active lesions examined. CCR7 immunostaining was predominantly confined to activated microglia at the lesion edges. Some perivascular DC-SIGN cells were found in close proximity to or contacting rare proliferating lymphocytes, most of which expressed the DC-SIGN ligand ICAM-3 and CD8. These data suggest that DCs recruited and maturing in MS lesions, where self-antigens are made available by continuous myelin destruction, may contribute to the local activation and expansion of presumably pathogenic T cells.     

JC virus viremia in interferon-β-treated and untreated Italian multiple sclerosis patients and healthy controls

Following the development of progressive multifocal leukoencephalopathy (PML) in two multiple sclerosis (MS) patients treated with natalizumab and interferon-beta (IFNbeta), a possible correlation between JC virus (JCV), the etiological agent of PML, and MS has received heightened interest. In particular, attention has focused on assessing whether IFNbeta treatment could affect the replication of JCV and thus its frequency in the peripheral blood of MS patients and whether the presence of JCV DNA in peripheral blood could be a predictive marker of the risk of developing PML. In order to answer to these questions, peripheral blood samples were collected from 59 INFbeta-treated, 39 untreated relapsing-remitting MS patients, and 98 healthy controls (HCs) and JCV DNA levels were determined and quantified by means of a real-time polymerase chain reaction (Q-PCR) assay. Overall, no differences were found in the presence or viral load of JCV DNA of MS patients and the HCs, but JCV DNA was significantly less frequent in the peripheral blood of IFNbeta-treated patients (13.6%) compared to the untreated MS patients (46.1%) and the healthy controls (28.6%). These results suggest that the presence of JCV in the blood of MS patients cannot be considered as a marker or a risk factor for PML development. In addition, they indicate that treatment with INFbeta can lead to the reduction of presence of the JCV genome in the peripheral blood of MS patients and, thus, that this drug probably does not increase the risk of PML in MS patients treated with IFNbeta.     

Dendritic cells in hyperplastic thymuses from patients with myasthenia gravis.

To investigate the role of dendritic cells (DCs) in the hyperplastic myasthenia gravis (MG) thymus, we studied the frequency and distribution of three mature DC phenotypes (CD83(+)CD11c(+), CD86(+)CD11c(+), and HLA-DR(+)CD11c(+)) in samples from patients with MG whose symptoms dramatically improved following thymectomy and in non-MG control thymuses. In hyperplastic MG thymuses, mature DCs were much more numerous in nonmedullary areas, such as the subcapsular/outer cortex; around the germinal centers; and in extralobular connective tissue, particularly around blood vessels. Mature DCs strongly coexpressed CD44 and appeared to be components of a CD44-highly positive (CD44(high)) cell population migrating from the vascular system. Furthermore, in the hyperplastic MG thymus, the expression of secondary lymphoid-tissue chemokine (SLC) markedly increased especially around extralobular blood vessels, where the CD44(high) cell population accumulated. These findings suggest that DCs may migrate into the hyperplastic thymus from the vascular system via mechanisms that involve CD44 and SLC. DCs may present self-antigens, thereby promoting the priming and/or boosting of potentially autoreactive T cells against the acetylcholine receptor.     

HIV and decreased risk of multiple sclerosis: role of low CD4+ lymphocyte count and male prevalence

In this retrospective case-control study, we compared the number of circulating lymphocyte subsets among 31 healthy controls, 18 naïve and 40 antiretroviral-treated HIV patients, 28 untreated and 18 treated relapsing-remitting multiple sclerosis (MS) patients. Lymphocyte subsets were no different between untreated MS patients and controls. Untreated and treated MS had a lower CD8+ count and a higher CD4+ number compared to untreated and treated HIV patients except similar CD4+ number between treated MS and HIV patients. CD4/CD8 ratio was lower in female HIV non-responders and in relapsing MS women compared, respectively, to female HIV responders and remitting MS women, and there were no differences in men.     

Autoreactivity to myelin antigens related to HLA associations with multiple sclerosis

Multiple sclerosis (MS) is considered as an immune process influenced by genetic and environmental factors. HLA-DR2 and -DR4 have been documented to be associated with MS. The HLA-dependent differences of immune response to myelin and other antigens might point out some relevant mechanisms in MS development The responses to myelin antigens and to PPD have been compared in 21 MS patients and 25 healthy controls (HCs) by primary proliferation and by short-term T-cell lines. There was a significantly higher response to MBP in DR2+ HCs compared to MS patients (SI: 5.9 versus 1.5, p = 0.02). In short-term T-cell lines, we observed a higher response to PLP30-49 in both DR4+ HCs and MS patients This response was significantly more frequent in DR4+ MS patients (34.6%) than both DR2+ MS patients (0%, p = 0.0001) and DR4+ HCs (7.7%, p = 0.001). The comparison between DR2+ and DR4+ MS patients has revealed that the response to MBP was also increased in DR4+ (p = 0.02). Among DR4+ groups, an increased PPD response was detected in HCs compared to MS (65.2% versus 33.3%, p = 0.01). These results may indicate that HLA-related differences to specific and recall antigens are detectable in MS and these differences may have implications in the disease pathogenesis.     

The peripheral endocannabinoid system and its association with biomarkers of inflammation in untreated patients with multiple sclerosis

Background and purpose

The endocannabinoid system (ECS) has been found altered in patients with multiple sclerosis (MS). However, whether the ECS alteration is present in the early stage of MS remains unknown. First, we aimed to compare the ECS profile between newly diagnosed MS patients and healthy controls (HCs). Next, we explored the association of the ECS, biomarkers of inflammation, and clinical parameters in newly diagnosed MS patients.

Methods

Whole blood gene expression of ECS components and levels of endocannabinoids in plasma were measured by real-time quantitative polymerase chain reaction and ultra-high-pressure liquid chromatography–mass spectrometry, respectively, in 66 untreated MS patients and 46 HCs.

Results

No differences were found in the gene expression or plasma levels of the selected ECS components between newly diagnosed MS patients and HCs. Interferon-γ, encoded by the gene IFNG, correlated positively (ρ = 0.60) with the expression of G protein-coupled receptor 55 (GPR55), and interleukin1β (IL1B) correlated negatively (ρ = −0.50) with cannabinoid receptor 2 (CNR2) in HCs.

Conclusions

We found no alteration in the peripheral ECS between untreated patients with MS and HC. Furthermore, our results indicate that the ECS has a minor overall involvement in the early stage of MS on inflammatory markers and clinical parameters when compared with HCs.     

Effects of interferon-beta on co-signaling molecules: upregulation of CD40, CD86 and PD-L2 on monocytes in relation to clinical response to interferon-beta treatment in patients with multiple sclerosis

Interferon-beta (IFN-beta) reduces disease activity in a subgroup of patients with relapsing remitting multiple sclerosis (MS). The mechanism of action as well as the pathophysiological basis of responsiveness to IFN-beta is not well understood. Since T-cell activation plays an important part in the pathophysiology of MS, we here investigated the effect of IFN-beta on the expression of co-signaling pathways (CD28-CD80/CD86, CD154-CD40, ICOS-ICOSL, PD-1-PD-L1/2) in MS patients and correlated the results with the clinical response to IFN-beta in individual patients. Expression of co-signaling molecules was measured by flow cytometry in vitro on peripheral blood mononuclear cells after incubation with IFN-beta, and in vivo in whole blood samples of 32 untreated and 24 IFN-beta treated MS patients, including 13 patients longitudinal. IFN-beta treatment induced upregulation of CD40, CD80, CD86, PD-L1 and PD-L2 on monocytes as well as PD-L1 on CD4+-T-cells in vitro and in vivo. IFN-beta treated MS patients were grouped into responders and non-responders on the basis of Kurtzkés EDSS (expanded disability status scale) progression and relapse rate. Upregulation of CD40, CD86 and PD-L2 on monocytes was associated with treatment response to IFN-beta (P < 0.001, P = 0.028 and P = 0.028, respectively). Our results show that IFN-beta upregulates co-stimulatory as well as co-inhibitory molecules in vitro and in vivo implicating that modulation of the balance between positive and negative co-stimulatory signals might be an important part of the mechanism of action of IFN-beta in MS. Upregulation of the expression of CD40, CD86 and PD-L2 may be useful as a predictive marker for clinical response to IFN-beta treatment at early timepoints during IFN-beta therapy.     

Long-term therapy with glatiramer acetate in multiple sclerosis: effect on T-cells

Glatiramer acetate (GA) is an immunotherapeutic drug for multiple sclerosis (MS). Several mechanisms of action have been demonstrated which target and affect T-cells that are specific for myelin antigen epitopes. We measured the in vitro proliferation of GA-responsive T-cells from untreated MS patients and from normal healthy subjects; in addition, we determined the effect of prolonged GA therapy or interferon-beta therapy on the in vitro proliferation of GA-responsive T-cells of MS patients. We found that GA induces the proliferation of T-cells isolated from individuals who have not been previously exposed to GA, and that long-term in vivo therapy of MS patients with GA abrogates the GA-induced proliferative response of T-cells. In GA-treated patients, there is no evidence of generalized immunosuppression; both tetanus toxoid and anti-CD3 induced proliferative responses remain unaffected. We propose that prolonged in vivo exposure to GA may result in the eventual induction of anergy or deletion of a population of GA-responsive cells that may also be T-cells that are pathogenic in MS. This mechanism of action, in addition to other mechanisms that have been demonstrated, suggests that GA has pleiotropic effects on the immune system in MS.     

Monocytes P2X7 purinergic receptor is modulated by glatiramer acetate in multiple sclerosis

The aim of this study is to investigate the expression of P2X7R, IL-1beta and the ATP activity modulating ecto-apyrase CD39 on peripheral blood monocytes of MS patients and to observe the possible effects of Glatiramer Acetate (GA) on such expression. Twelve RR treatment-free MS patients were selected and peripheral blood monocytes were obtained. The expression of P2X7R, IL-1beta and CD39 on monocytes was investigated by qrt-PCR. The in vitro effects of GA on the expression of monocytes stimulated with BzATP (a potent P2X7R agonist)-were evaluated. Ten healthy donors (HDs) were similarly studied. Finally, 5 MS patients were given GA therapy and the monocytes obtained before treatment, after 3 and 12 months of GA treatment were similarly investigated. No differences were found in P2X7R, IL-1beta and CD39 expression between patients and controls. In MS Bz-ATP stimulated monocytes, GA pre-conditioning clearly downregulated P2X7R (p=0.003) but IL-1beta expression also showed a decreasing trend (p=0.07). Conversely, CD39 showed an increasing trend (p=0.07). Similar evidence was found in HDs. GA in vivo treatment induced a reduction in the expression that was clear for P2X7R and CD39 (p<0.05) but only not significant for IL-1beta after 12 months of treatment. Monocytes from both MS and control subjects express P2X7R, IL-1beta and CD39, and GA seems to interfere with such expression.     

Potassium channels Kv1.3 and Kv1.5 are expressed on blood-derived dendritic cells in the central nervous system

OBJECTIVE: Potassium (K(+)) channels on immune cells have gained attention recently as promising targets of therapy for immune-mediated neurological diseases such as multiple sclerosis (MS). We examined K(+) channels on dendritic cells (DCs), which infiltrate the brain in MS and may impact disease course. METHODS: We identified K(+) channels on blood-derived DCs by whole-cell patch-clamp analysis, confirmed by immunofluorescent staining. We also stained K(+) channels in brain sections from MS patients and control subjects. To test functionality, we blocked K(v)1.3 and K(v)1.5 in stimulated DCs with pharmacological blockers or with an inducible dominant-negative K(v)1.x adenovirus construct and analyzed changes in costimulatory molecule upregulation. RESULTS: Electrophysiological analysis of DCs showed an inward-rectifying K(+) current early after stimulation, replaced by a mix of voltage-gated K(v)1.3- and K(v)1.5-like channels at later stages of maturation. K(v)1.3 and K(v)1.5 were also highly expressed on DCs infiltrating MS brain tissue. Of note, we found that CD83, CD80, CD86, CD40, and interleukin-12 upregulation were significantly impaired on K(v)1.3 and K(v)1.5 blockade. INTERPRETATION: These data support a functional role of K(v)1.5 and K(v)1.3 on activated human DCs and further define the mechanisms by which K(+) channel blockade may act to suppress immune-mediated neurological diseases.     

Glatiramer acetate (GA) induces IL-13/IL-5 secretion in naive T cells

In order to define possible mechanisms of immunomodulation by glatiramer acetate (GA), we investigated the primary in vitro cytokine response of peripheral blood mononuclear cells (PBMCs) and T-cell subpopulations. In PBMCs from healthy subjects and untreated patients with multiple sclerosis (MS) GA-induced T-cell proliferation and mRNA expression/cytokine, secretion of IL-13 and IL-5 but not of IL-10, TGF-beta or IL-12, IL-4 was detected at the mRNA level only. IFN-gamma was induced in a few subjects at very low concentrations. The response to GA was driven by the CD4(+)/CD45RA(+) T-cell subpopulation and was mediated by T-cell receptor (TCR) engagement as determined by anti-TCR blocking antibodies. The findings are compatible with the hypothesis that GA functions as partial or weak TCR-agonist activating naive T cells to produce the Th2 cytokines IL-13 and IL-5.