Serotonin decreases the production of Th1/Th17 cytokines and elevates the frequency of regulatory CD4+ T-cell subsets in multiple sclerosis patients.

Excessive levels of proinflammatory cytokines in the CNS are associated with reduced serotonin (5-HT) synthesis, a neurotransmitter with diverse immune effects. In this study, we evaluated the ability of exogenous 5-HT to modulate the T-cell behavior of patients with MS, a demyelinating autoimmune disease mediated by Th1 and Th17 cytokines. Here, 5-HT attenuated, in vitro, T-cell proliferation and Th1 and Th17 cytokines production in cell cultures from MS patients. Additionally, 5-HT reduced IFN-γ and IL-17 release by CD8+ T cells. By contrast, 5-HT increased IL-10 production by CD4+ T cells from MS patients. A more accurate analysis of these IL-10-secreting CD4+ T cells revealed that 5-HT favors the expansion of FoxP3+ CD39+ regulatory T cells (Tregs) and type 1 regulatory T cells. Notably, this neurotransmitter also elevated the frequency of Treg17 cells, a novel regulatory T-cell subset. The effect of 5-HT in upregulating CD39+ Treg and Treg17 cells was inversely correlated with the number of active brain lesions. Finally, in addition to directly reducing cytokine production by purified Th1 and Th17 cells, 5-HT enhanced in vitro Treg function. In summary, our data suggest that serotonin may play a protective role in the pathogenesis of MS.

Different interleukin-17-secreting Toll-like receptor+ T-cell subsets are associated with disease activity in multiple sclerosis.

Signalling through Toll-like receptors (TLRs) may play a role in the pathogenesis of autoimmune diseases, such as multiple sclerosis (MS). In the present study, the expression of TLR-2, -4 and -9 was significantly higher on CD4+ and CD8+ T-cells from MS patients compared to healthy individuals. Following in-vitro activation, the proportion of interleukin (IL)-17+ and IL-6+ CD4+ and CD8+ T-cells was higher in the patients. In addition, the proportion of IFN-γ-secreting TLR+ CD8+ T-cells was increased in MS patients. Among different IL-17+ T-cell phenotypes, the proportion of IL-17+ TLR+ CD4+ and CD8+ T-cells producing IFN-γ or IL-6 were positively associated with the number of active brain lesions and neurological disabilities. Interestingly, activation of purified CD4+ and CD8+ T-cells with ligands for TLR-2 (Pam3Csk4), TLR-4 [lipopolysaccharide (LPS)] and TLR-9 [oligodeoxynucleotide (ODN)] directly induced cytokine production in MS patients. Among the pathogen-associated molecular patterns (PAMPs), Pam3Csk4 was more potent than other TLR ligands in inducing the production of all proinflammatory cytokines. Furthermore, IL-6, IFN-γ, IL-17 and granulocyte-macrophage colony-stimulating factor (GM-CSF) levels produced by Pam3Csk4-activated CD4+ cells were directly associated with disease activity. A similar correlation was observed with regard to IL-17 levels released by Pam3Csk4-stimulated CD8+ T-cells and clinical parameters. In conclusion, our data suggest that the expansion of different T helper type 17 (Th17) phenotypes expressing TLR-2, -4 and -9 is associated with MS disease activity, and reveals a preferential ability of TLR-2 ligand in directly inducing the production of cytokines related to brains lesions and neurological disabilities.

Risk factors for convertion to clinically defined multiple sclerosis after clinically isolated syndrome in a racially mixed Brazilian cohort.

UNLABELLED: Clinically isolated syndrome may reflect the first symptom of Multiple Sclerosis. Though more prevalent in Caucasians, MS can also affect Afrodescendts. Modifying disease drugs can delay convertion to clinically defined multiple sclerosis, therefore, identify patients at a higher risk of convertion is important. However data of risk factors in racially mixed population are scarce. OBJECTIVES: To analyze predictor factors to the conversion from CIS to CDMS in a mixed race Brazilian cohort. PATIENTS AND METHODS: It is a prognostic observational retrospective study, in 122 patients from MS referential center at Hospital da Lagoa, Rio de Janeiro-Brazil. Demographic and clinical features, as well as MRI and cerebrospinal fluid data were analyzed. RESULTS: After five years follow-up 87.3% converted to CDMS. Regarding to median time of conversion, there was no difference between gender, race, age at onset, mono or polysymptomatic presentation. Cerebellar CIS significantly reduced time to second event; likewise sphincter impairment. Considering DMD, patients without treatment converted earlier. CONCLUSION: Ancestry did not influence conversion risk. Cerebellar and shpincter impairment as well as MRI criteria both Barkhof/Tintoré and Swanton were important predictors. In future studies it should be also analysed the risk factors of progression in mixed race populations.

Combined exercise training reduces fatigue and modulates the cytokine profile of T-cells from multiple sclerosis patients in response to neuromediators.

Fatigue is a common and disabling symptom of multiple sclerosis (MS), a classical Th1- and Th17-mediated autoimmune disease. There is no effective pharmacological treatment for fatigue, but some reports point towards beneficial effects of physical activity on management of the fatigue in MS patients. As both MS and fatigue have been associated with dysregulated cytokine network production, the objective of the present study was to evaluate the impact of a physical activity program consisting of a 12-week series of combining Pilates and aerobic exercises on fatigue severity, determined by FSS, and cytokine production, quantified by ELISA, by T cells from MS patients (n=08) with low disability (EDSS≤2). The results showed decrease in FSSs in all patients at the end of physical activity intervention. Regarding the cytokines, a significant reduction of IL-22 release was observed in polyclonally-activated T cells form MS patients post-training follow-up. Interestingly, while the physical activity attenuated the ability of dopamine in up-regulating Th17-related cytokines, it enhanced the anti-inflammatory effects of serotonin, evidenced by high IL-10 production. In summary, all results suggest that programmed physical activity has beneficial effects on management of fatigue in MS patients, and it could be related, at least in part, to its ability in regulating neuroimmune parameters into T cell compartment.

Interleukin-17- and interleukin-22-secreting myelin-specific CD4(+) T cells resistant to corticoids are related with active brain lesions in multiple sclerosis patients.

Multiple sclerosis (MS) is thought to be an autoimmune disorder. It is believed that immunological events in the early stages have great impact on the disease course. Therefore, we aimed to evaluate the cytokine profile of myelin basic protein (MBP)-specific T cells from MS patients in the early phase of the disease and correlate it to clinical parameters, as well as to the effect of in vitro corticoid treatment. Peripheral T cells from MS patients were stimulated with MBP with our without hydrocortisone for 5 days. The cytokines level were determined by ELISA. The number of active brain lesions was determined by MRI scans, and the neurological disabilities were assessed by Expanded Disability Status Scale scores. Our results demonstrated that MS-derived T cells responded to MBP by producing high levels of T helper type 1 (Th1) and Th17 cytokines. Although the production of interleukin-6 (IL-6), granulocyte-macrophage colony-stimulating factor, IL-17 and IL-22 was less sensitive to hydrocortisone inhibition, only IL-17 and IL-22 levels correlated with active brain lesions. The ability of hydrocortisone to inhibit IL-17 and IL-22 production by MBP-specific CD4(+) T cells was inversely related to the number of active brain lesions. Finally, the production of both cytokines was significantly higher in cell cultures from Afrodescendant patients and it was less sensitive to hydrocortisone inhibition. In summary, our data suggest that IL-17- and IL-22-secreting CD4(+) T cells resistant to corticoids are associated with radiological activity of the MS in early stages of the disease, mainly among Afrodescendant patients who, normally, have worse prognosis.

Role of high mobility group box protein 1 (HMGB1) in peripheral blood from patients with multiple sclerosis.

BACKGROUND: High mobility group box protein 1 (HMGB1) is a transcriptional regulator that is receiving increasing attention in autoimmune disorders including multiple sclerosis (MS). Here, we investigated the role of HMGB1 in the peripheral blood compartment from MS patients. METHODS: HMGB1 mRNA expression levels were determined by PCR in peripheral blood mononuclear cells (PBMC) of 29 healthy controls and 57 untreated MS patients (26 with relapsing-remitting MS - RRMS, 13 with secondary progressive MS - SPMS, and 18 with primary progressive MS - PPMS). HMGB1 protein levels were measured by ELISA in serum samples from 18 HC and 37 untreated MS patients (13 with RRMS, 14 with SPMS, and 10 with PPMS). RESULTS: HMGB1 expression levels were increased in PBMC from the whole MS group compared with controls (P = 0.03). Further stratification of the MS group revealed higher expression levels in PBMC from patients with relapse-onset MS, and differences were statistically significant for RRMS patients compared with PPMS patients and controls (P = 4 × 10(-5) and P = 0.005, respectively) and also for SPMS patients compared with PPMS patients (P = 0.001). HMGB1 serum levels were increased in the whole MS group compared with controls (P = 2 × 10(-4)). In MS clinical forms, the highest HMGB1 serum levels were observed in RRMS patients, and differences were statistically significant compared to PPMS patients (P = 5 × 10(-5)), SPMS patients (P = 0.001), and controls (P = 0.001). CONCLUSIONS: These results point to a role of HMGB1 mRNA and protein levels as disease activity biomarkers to discriminate the more inflammatory relapse-onset MS forms, particularly RRMS, from the less inflammatory PPMS form of the disease.

Dopamine favors expansion of glucocorticoid-resistant IL-17-producing T cells in multiple sclerosis.

Dopamine (DA) is a neurotransmitter produced mainly in the central nervous system (CNS) that has immunomodulatory actions on T cells. As the multiple sclerosis (MS) has long been regarded as an autoimmune disease of CNS mediated by T cells, the objective of this study was to evaluate the impact of DA on in vitro functional status of T cells from relapsing-remitting (RR)-MS patients. Peripheral T-cells from RR-MS patients were activated by mitogens and cell proliferation and cytokine production were assayed by [(3)H]-thymidine uptake and ELISA, respectively. Our results demonstrated that DA enhanced in vitro T cell proliferation and Th17-related cytokines in MS-derived cell cultures. In addition, this catecholamine reduced Treg-related cytokines (IL-10 and TGF-ß) release by activated CD4(+) T cells. These DA-induced effects on T cells were mainly dependent on IL-6 production by both polyclonally-activated CD4(+) T cells and LPS-stimulated monocytes. Furthermore, the production of IL-17 and IL-6 by MS-derived T cells was directly related with neurological disability (EDSS score), and the release of these cytokines was less sensitive to glucocorticoid inhibition in MS patients than in control group, mainly after DA addition. In conclusion, our data suggest that DA amplifies glucocorticoid-resistant Th17 phenotype in MS patients, and this phenomenon could be, at least in part, due to its ability to induce IL-6 production by monocytes and CD4(+) T cells.

Endogenous interleukin-6 amplifies interleukin-17 production and corticoid-resistance in peripheral T cells from patients with multiple sclerosis.

Interleukin-6 (IL-6) has been implicated in the induction of pathogenic IL-17-producing T cells in autoimmune diseases, and studies evaluating the role of this cytokine in T-cell function in patients with multiple sclerosis (MS) are lacking. Our objective was to evaluate the role of IL-6 receptor (IL-6R) signalling on in vitro functional status of T cells from patients with relapsing-remitting MS during clinical remission. Our results demonstrated that, even during the remission phase, activated T cells from patients produce higher levels of IL-17, and this cytokine was positively correlated with disease severity, as determined by Expanded Disability Status Scale score. In the MS group, the blockade of IL-6R signalling by anti-IL-6R monoclonal antibody reduced IL-17 production and elevated IL-10 release by activated CD4(+) T cells, but it did not alter the production of these cytokines by activated CD8(+) T cells. Blockade of IL-6R signalling also reduced the ability of monocytes to up-regulate T helper type 17 phenotype in patients with MS. Finally, both cell proliferation and IL-17 release by CD4(+) and, mainly, CD8(+) T cells from patients with MS were less sensitive to hydrocortisone inhibition than control group. Interestingly, IL-6R signalling blockade restored the ability of hydrocortisone to inhibit both T-cell proliferation and IL-17 production. Collectively, these results suggest that IL-6 might be involved in MS pathogenesis by enhancing IL-17 production and reducing corticoid inhibitory effects on activated T cells.

Produção de interleucina-10 na gestação reduz a taxa de replicação do HIV-1 em culturas de linfócitos maternos / Interleukin-10 production during pregnancy reduces HIV-1 replicaction in cultures of maternal lymphocytes

OBJETIVO: avaliar a proliferação de células T e a produção de citocinas em gestantes infectadas pelo HIV-1 e seu impacto na replicação viral in vitro. MÉTODOS: sangue periférico de 12 gestantes infectadas pelo HIV-1 e de seus neonatos, bem como de 10 gestantes HIV-1 negativas, foi colhido e a quantidade de linfócitos TCD4+ e TCD8+ periféricos foi avaliada por citometria de fluxo. Para obter plasma ou células mononucleares periféricas (PBMC), as amostras foram centrifugadas na ausência ou presença de um gradiente de Ficoll-Hypaque, respectivamente. As PBMC foram mantidas em cultura por sete dias na presença de fito-hemaglutinina mais IL-2 recombinante e a resposta linfoproliferativa de células T foi analisada pelo método de exclusão em azul de Trypan. Em alguns experimentos, as culturas foram mantidas na presença adicional de anticorpo anti-IL-10. Os plasmas e sobrenadantes das culturas de PBMC ativadas foram submetidos à análise da produção de citocinas, pelo método ELISA indireto, e a carga viral, detectada pelo RT-PCR. RESULTADOS: independente da carga viral plasmática, a resposta linfoproliferativa em culturas de células obtidas de gestantes infectadas pelo HIV foi inferior às amostras normais [4,2±0,37 vs 2,4±0,56 (x 10(6)) células/mL; p<0.005]. Tanto em gestantes normais quanto em pacientes com cargas virais baixas, os níveis de IL-10 foram mais elevados que os das gestantes com elevada replicação viral (9.790±3.224 vs 1.256±350 pg/mL; p=0.002). Níveis elevados de TNF-alfa no soro (7.200±2.440 vs 510±476 pg/mL) e nas culturas de células (21.350±15.230 vs 1.256±350 pg/mL) correlacionaram-se à carga viral plasmática elevada e a infecção neonatal. O bloqueio da IL-10 endógena com anticorpos anti-IL-10 aumentou a replicação do HIV-1 em cultura de células. CONCLUSAO: nossos resultados sugerem que a IL-10 exerce influência negativa na replicação viral, o que provavelmente contribui para reduzir o risco de infecção vertical.