Here we present a comprehensive mass cytometry analysis of peripheral innate lymphoid cell (ILC) subsets in relapsing/remitting MS (RRMS) patients prior to and after onset of cladribine tablets ...(CladT). ILC analysis was conducted on CyTOF data from peripheral blood mononuclear cells (PBMC) of MS patients before, 2 and 6 months after onset of CladT, and non-MS controls. Dimensionality reduction was used for immunophenotyping ILC subsets. CladT reduced all ILC subsets, except for CD56bright NK cells and ILC2. Furthermore, CD38+ NK cell and CCR6+ ILC3 were excluded from CladT-induced immune cell reductions. Post-CladT replenishment by immature ILC was noted by increased CD5+ ILC1 proportions at 2 months, and boosted CD38-CD56bright NK cell numbers at 6 months. CladT induce immune cell depletion among ILC but exclude CD56bright NK cells and ILC2 subsets, as well as CD38+ NK cell and CCR6+ ILC3 immunophenotypes. Post-CladT ILC expansions indicate ILC reconstitution towards a more tolerant immune system phenotype.
In this study, we examined the effects of interleukin‐10 (IL‐10) on the outcome of experimental cerebral malaria (CM), a lethal neurological syndrome that occurs in susceptible strains of mice after ...infection with Plasmodium berghei ANKA (PbA). Constitutive IL‐10 mRNA levels were significantly higher in the spleen and brain of resistant animals. In vivo neutralization of endogenous IL‐10 in CM‐resistant mice induced the neurological syndrome in 35·7% of these mice, as opposed to 7·7% in controls. IL‐10 inhibited PbA antigen‐specific interferon‐γ (IFN‐γ) production in vitro but not tumour necrosis factor (TNF) serum levels in vivo. Susceptible mice, on the other hand, were significantly protected against CM when injected with recombinant IL‐10. Overall, our findings suggest that IL‐10 plays a protective role against experimental cerebral malaria.
Tumor necrosis factor-alpha (TNF) is known to be an important mediator in the pathogenesis of several inflammatory diseases. Vascular endothelial cells represent a major target of TNF effects. ...Platelet sequestration has been found in brain microvessels during experimental cerebral malaria and lung in experimental pulmonary fibrosis, implying that it may participate in TNF-dependent microvascular pathology. In this study, we investigated the mechanisms of platelet-endothelial interaction, using co-cultures between platelets and TNF-activated mouse brain microvascular endothelial cells (MVECs). Adhesion and fusion of platelets to MVECs was evidenced by electron microscopy, dye transfer, and flow cytometry. It was induced by TNF and interferon-gamma and depended on LFA-1 expressed on the platelet surface and ICAM-1 expressed on MVECs. The adhesion and fusion also led to the transfer of platelet markers on the MVEC surface, rendering these more adherent for leukocytes, and to an enhanced MVEC sensitivity to TNF-induced injury. These results suggest that platelets can participate in TNF-induced microvascular pathology.
Cytokine regulation was compared in three groups of Gabonese patients with Plasmodium falciparum malaria before and after therapy; adults with uncomplicated malaria, children with uncomplicated ...malaria, and children with severe malaria. Plasma levels of tumor necrosis factor (TNF), interleukin-6 (IL-6), IL-8, TNF receptors (TNF R), and the TNF/TNF R ratios were significantly higher in severe malaria compared with uncomplicated malaria. High plasma levels of all immunoregulatory molecules were associated with slow cure after therapy. In all patients, phytohemagglutinin-induced cytokine production was depressed on admission compared with convalescence. A significant difference was the higher TNF production capacity in patients with severe malaria on day 2 and day 5 compared with that in patients with uncomplicated malaria. In contrast to IL-6 and IL-8, a high TNF production capacity during the acute phase of malaria predicted a rapid clinical and parasitologic cure in the patients. These findings illustrate the dual role of TNF in the protection and pathology of malaria.
No biological parameter is currently available as a specific marker of multiple sclerosis (MS) activity. The aim of this study was to determine whether an evolution of the neurological disability is ...associated with a modified profile of cytokine production. Clinical disease activity was quantitated by the Kurtzke's expanded disability status scale (EDSS). Whole blood was stimulated with phytohemagglutinin (PHA) for 2 hours at 37 degrees C and the activated plasma was assayed for Tumor necrosis factor alpha (TNF-alpha) and Interleukin-1 beta (IL-1 beta). Relapsing-remitting MS patients enduring a relapse (RRMS, in relapse) (721 +/- 58 pg/ml, n = 27) and chronic progressive MS (CPMS) patients (516 +/- 33 pg/ml, n = 17) had an higher TNF-alpha production capacity as compared to healthy subjects (143 +/- 25 pg/ml, n = 17), RRMS, stable patients, (123 +/- 11 pg/ml, n = 26) or other neurological diseases (OND) without immunological or inflammatory disease in the peripheral immune compartment (131 +/- 24 pg/ml, n = 14) (t test: p < 0.0001). IL-1 beta production was also significantly higher but to a lesser extent in the same conditions. Concentration of TNF-alpha was also found to be significantly higher in the cerebrospinal fluid (CSF) of CPMS patients (199 +/- 7.8 pg/ml, n = 7, p < 0.0001) but also in RRMS, in relapse (149 +/- 5.7 pg/ml, n = 11, p < 0.05) as compared to RRMS, stable (130 +/- 4.4 pg/ml, n = 7) or OND without inflammatory or immunological disease of the central nervous system (CNS) (142 +/- 6.2 pg/ml, n = 8).
CC chemokine receptor (CCR)4, a high affinity receptor for the CC chemokines thymus and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC), is expressed in the thymus and ...spleen, and also by peripheral blood T cells, macrophages, platelets, and basophils. Recent studies have shown that CCR4 is the major chemokine receptor expressed by T helper type 2 (Th2) polarized cells. To study the in vivo role of CCR4, we have generated CCR4-deficient (CCR4(-/-)) mice by gene targeting. CCR4(-/-) mice developed normally. Splenocytes and thymocytes isolated from the CCR4(-/-) mice failed to respond to the CCR4 ligands TARC and MDC, as expected, but also surprisingly did not undergo chemotaxis in vitro in response to macrophage inflammatory protein (MIP)-1alpha. The CCR4 deletion had no effect on Th2 differentiation in vitro or in a Th2-dependent model of allergic airway inflammation. However, CCR4(-/-) mice exhibited significantly decreased mortality on administration of high or low dose bacterial lipopolysaccharide (LPS) compared with CCR4(+/+) mice. After high dose LPS treatment, serum levels of tumor necrosis factor alpha, interleukin 1beta, and MIP-1alpha were reduced in CCR4(-/-) mice, and decreased expression of MDC and MIP-2 mRNA was detected in peritoneal exudate cells. Analysis of peritoneal lavage cells from CCR4(-/)- mice by flow cytometry also revealed a significant decrease in the F4/80(+) cell population. This may reflect a defect in the ability of the CCR4(-/-) macrophages to be retained in the peritoneal cavity. Taken together, our data reveal an unexpected role for CCR4 in the inflammatory response leading to LPS-induced lethality.
Acute graft-versus-host disease (GvHD) is a serious complication after allogeneic bone marrow transplantation. Donor-derived T cells infiltrate recipient target organs and cause severe tissue damage, ...often leading to death of the affected patient. Tissue destruction is a direct result of donor CD8+ T cell activation and cell-mediated cytotoxicity. IL-18 is a novel pro-inflammatory cytokine with potent T(h)1 immune response-promoting and cytotoxic T lymphocyte (CTL)-inducing activity. IL-18 is strongly induced in experimental mouse models and human patients with acute GvHD. However, the precise role of IL-18 in the development of acute GvHD is still unknown. In this study, we have used IL-18-binding protein, a soluble IL-18 decoy receptor, to specifically neutralize IL-18 in vivo and in vitro. Our results demonstrate that IL-18 is induced during GvHD. However, its effect in the induction of GvHD appears to be redundant, since neutralization of IL-18 does not alter any disease parameter analyzed. Our study further shows that IFN-gamma production and CTL induction upon activation by T cell mitogens or by alloantigen does not involve IL-18-mediated amplification, in contrast to lipopolysaccharide-induced IFN-gamma production. We conclude that IL-18 expression correlates with the course of GvHD; however, its effect is dispensable for IFN-gamma and CTL induction for the initiation phase of this disease, most likely due to direct, IL-18-independent, CTL activation.
In the present study, we investigated 91 patients with Plasmodium falciparum malaria of different severity in a highly endemic area. Patients were examined at least twice daily until clearance of ...parasites and fever. Plasma cytokine concentrations without and after ex vivo PHA stimulation of whole blood were determined. On admission we found elevated plasma concentrations of TNF, IFN-gamma, and IL-10 compared to levels during and after chemotherapy. Plasma TNF levels on admission were significantly different between patients with severe and mild malaria (differentiated in schoolchildren and adults). The PHA elicited TNF production capacity of peripheral blood leucocytes was suppressed during the acute phase of malaria. High TNF production capacity was associated with faster fever clearance and parasite clearance and, in patients with severe malaria, with higher blood glucose levels. In conclusion we observed circulating TNF concentrations in malaria patients dependent on the severity of disease, which is itself dependent on age, and an association of a high TNF production capacity with parameters for accelerated cure and good prognosis.
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