Elaine C. Oliveira

Vitamin D3 induces IDO+ tolerogenic DCs and enhances Treg, reducing the severity of EAE.

A growing body of evidence supports the hypothesis that vitamin D is an important environmental factor in the etiology of T‐cell‐mediated autoimmune diseases such as multiple sclerosis (MS).

Plasmacytoid dendritic cells are increased in cerebrospinal fluid of untreated patients during multiple sclerosis relapse

The plasmacytoid dendritic cells (pDCs) express a high level of Toll-like receptor 9 (TLR-9), which recognizes viral DNA. Activated via TLR-9, pDCs also secrete large amounts of type I interferon which are involved either in stimulation or down regulation of immune response in multiple sclerosis (MS). In the present study, we determinate pDCs levels by flow cytometry in Cerebrospinal Fluid (CSF) and Peripheral Blood from MS patients in relapsing and in remitting phases of the disease, comparing with other non-inflammatory diseases (OND). We provide evidence that MS patients in relapse without any treatment have a significantly (p < 0.01) higher percentage of pDCs in CSF than do patients in remission or those with OND. No change in the percentage of pDCs was observed in the peripheral blood of any of these patients. The increase of pDCs in central nervous system during relapse may be explained either by a virus infection or a down regulatory process.

Interferon beta modulates experimental autoimmune encephalomyelitis by altering the pattern of cytokine secretion.

The mechanism of action underlying the beneficial effect of IFNbeta in Multiple Sclerosis is poorly understood. Experimental Autoimmune Encephalomyelitis (EAE) is the experimental model for Multiple Sclerosis; therefore, we investigated the effects of recombinant mouse IFNbeta on the severity of EAE induced in SJL mice and on cytokine production by Th1 and Th2 lymphocytes. The results indicated that rmIFN beta reduced the disease activity with an I.P. dosage of 10,000 U/day every other day, and successfully treated EAE mice revealed reduced amounts of IFN gamma; no changes in the levels of IL4 were observed, although thera was a significant increase in IL10 and TGFbeta production. Beneficial effects on EAE are associated with inhibition of inflammatory cytokines and stimulation of anti-inflammatory cytokines.

Disappearance of cerebrospinal fluid oligoclonal bands after natalizumab treatment of multiple sclerosis patients

Intrathecal immunoglobulin synthesis in an oligoclonal pattern is the most common immunologic abnormality detected in MS patients. Various treatments, such as immunomodulators and immunosuppressors, have not been found to modify it. Natalizumab hinders migration of encephalitogenic T-cells into the central nervous system (CNS), reducing inflammatory response. Its impact on CSF oligoclonal bands (OCBs) has not been demonstrated. This report describes its effect in four out of six patients with multiple sclerosis after a mean of 10 infusions: the CSF was negative for OCBs at the second lumbar puncture. In conclusion, natalizumab treatment can reduce CSF OCBs to undetectable levels, although the clinical significance of this observation is not yet known.

Nitric Oxide and TNFα Effects in Experimental Autoimmune Encephalomyelitis Demyelination

The involvement of inducible nitric oxide synthase (iNOS), which plays various roles in the progression of autoimmune diseases, was studied in iNOS knockout (KO) mice and wild-type (WT) controls with respect to experimental autoimmune encephalomyelitis (EAE). The iNOS (KO) mice presented a less severe form of the disease than the WT control mice. Although the levels of TNFα decreased in the periphery in both groups, an increase in the number of TNFα-positive cells was detected in the central nervous system during the acute phase of EAE in the WT mice, but not in the KO mice. These findings suggest that NO and TNFα contribute to the pathogenesis of acute EAE.

Interferon-beta modifies the peripheral blood cell cytokine secretion in patients with multiple sclerosis

Immunotherapy with Interferon-beta (IFNbeta) results in remarkably beneficial effects in patients with relapsing-remitting multiple sclerosis (MS), although the mechanisms by which it exerts these beneficial effects remain poorly understood. An investigation was made of the effects of IFNbeta on pro-inflammatory and anti-inflammatory cytokine production in peripheral blood cells in MS patients, both untreated and those undergoing immunotherapy, as well as in healthy controls. Results show a significant increase in the production of pro-inflammatory cytokines such as TNFalpha, IFNgamma and IL-12 in the plasma and in the supernatant of leukocyte cultures from MS patients with the untreated disease; IFNbeta administration significantly reduced the levels of TNFalpha and IFNgamma, with no changes in the level of IL-12. The Interferon-beta therapy also led to a significant increase in the production of IL-10, as well as a slight increase in that of TGFbeta. The reduction in pro-inflammatory cytokine production in the treated MS patient group, accompanied by a simultaneous increase in the production of anti-inflammatory cytokines and the reduction of relapse rates suggests that the beneficial effects of IFNbeta immunotherapy result, at least in part, from the modulation of cytokine patterns.

Cytokines and intrathecal IgG synthesis in multiple sclerosis patients during clinical remission

Cytokines and intrathecal IgG synthesis were determined in the cerebrospinal fluid (CSF) and sera to evaluate inflammatory activity in multiple sclerosis (MS) patients during clinical remission. Although the disease was stable, there had been a significant increase of proinflammatory cytokines such as TNFalpha and IFNgamma in the CSF and serum, with no significant changes of IL12 and IL10 production. The changes in the cytokine production patterns were associated with an increase of leukocytes in the CSF, as well as the presence of oligoclonal bands suggesting intrathecal IgG synthesis. These results suggest that even when the disease is clinically silent, one can observe inflammatory activity in these MS patients.

Neuropathy of Gastrointestinal Chagas' Disease: Immune Response to Myelin Antigens

Most reports of autoimmune response during infection with the parasite Trypanosoma cruzi have dealt with the cardiomyopathic form of Chagas’ disease, but little is known about the mechanisms of tissue damage involved in the gastrointestinal form, which was studied here. Chronically infected patients with a severe gastrointestinal form of Chagas’ disease present increased antibody production and proliferative responses to peripheral myelin components, such as myelin basic protein (MBP), which is homologous to the P1 protein fraction of peripheral myelin. T lymphocytes preferentially recognize a region on the MBP molecule (1–30), which suggests that the MBP is a potential target on the peripheral nerve for autoimmune reactions in patients with gastrointestinal lesions resulting from Chagas’ disease.

Up-regulation of T lymphocyte and antibody production by inflammatory cytokines released by macrophage exposure to multi-walled carbon nanotubes

Our data demonstrate that multi-walled carbon nanotubes (MWCNTs) are internalized by macrophages, subsequently activating them to produce interleukin (IL)-12 (IL-12). This cytokine induced the proliferative response of T lymphocytes to a nonspecific mitogen and to ovalbumin (OVA). This increase in the proliferative response was accompanied by an increase in the expression of pro-inflammatory cytokines, such as interferon-gamma (IFNγ), tumor necrosis factor-alpha (TNFα) and IL-6, in mice inoculated with MWCNTs, whether or not they had been immunized with OVA. A decrease in the expression of transforming growth factor-beta (TGFβ) was observed in the mice treated with MWCNTs, whereas the suppression of the expression of both TGFβ and IL-10 was observed in mice that had been both treated and immunized. The activation of the T lymphocyte response by the pro-inflammatory cytokines leads to an increase in antibody production to OVA, suggesting the important immunostimulatory effect of carbon nanotubes.

Effect of surgical treatment on the cellular immune response of gastric cancer patients.

Patients with gastric cancer have a variety of immunological abnormalities. In the present study the lymphocytes and their subsets were determined in the peripheral blood of patients with gastric cancer (N = 41) both before and after surgical treatment. The percent of helper/inducer CD4 T cells (43.6 +/- 8.9) was not different after tumor resection (43.6 +/- 8.2). The percent of the cytotoxic CD8+ T cell population decreased significantly, whether patients were treated surgically (27.2 +/- 5.8%, N = 20) or not (27.3 +/- 7.3%, N = 20) compared to individuals with inflammatory disease (30.9 +/- 7.5%) or to healthy individuals (33.2 +/- 7.6%). The CD4/CD8 ratio consequently increased in the group of cancer patients. The peripheral blood lymphocytes of gastric cancer patients showed reduced responsiveness to mitogens. The defective blastogenic response of the lymphocytes was not associated with the production of transforming growth factor beta (TGF- ) since the patients with cancer had reduced production of TGF- Beta1 (269 +/- 239 pg/ml, N = 20) in comparison to the normal individuals (884 +/- 175 pg/ml, N = 20). These results indicate that the immune response of gastric cancer patients was not significantly modified by surgical treatment when evaluated four weeks after surgery and that the immunosuppression observed was not due to an increase in TGF- 1 production by peripheral leukocytes.