Targeting fibroblast growth factor-inducible-14 signaling protects from chronic relapsing experimental autoimmune encephalomyelitis.

The TNF-related weak inducer of apoptosis (TWEAK) is a TNF family member mediating proinflammatory effects by its receptor fibroblast growth factor-inducible-14 (Fn14). We studied the role of TWEAK/Fn14 in experimental autoimmune encephalomyelitis (EAE) by protein vaccination with TWEAK and Fn14 and recombinant TWEAK-DNA, respectively. TWEAK-DNA vaccination worsened the clinical course of EAE and increased central nervous system (CNS) inflammation. TWEAK increased the secretion of CCL2 [monocyte chemotactic protein-1 (MCP-1)] by CNS endothelial cells and astrocytes in vitro, suggesting CCL2 as a critical mediator of TWEAKs proinflammatory effects. Vaccination with the extracellular domain of TWEAK or with Fn14 resulted in the induction of specific inhibitory antibodies and an amelioration of EAE signs in two different models in rats and mice. Spinal cord inflammatory infiltrates were significantly diminished. Purified IgG from TWEAK- or Fn14-vaccinated rats prevented TWEAK-induced production of CCL2 by endothelial cells. Blocking Fn14 signaling represents a novel approach with potential for the treatment of CNS autoimmunity.

Investigations of cytokine production in whole blood cultures of paranoid and residual schizophrenic patients.

In an attempt to define potential immunological dysfunctions in schizophrenia, we determined the production of interleukin-2 (IL-2), interleukin-4 (IL-4), interferon-gamma (IFN-gamma), and soluble IL-2 receptor (sIL-2R) in a whole-blood assay after stimulation with phytohemagglutinin (PHA) as well as the serum concentrations of sIL-2R. Because CD4+CD45RO+T cells are the main producers of IFN-gamma, we determined the percentage of these cells, as well as of panT, CD4+T, and CD8+T cells, by flow cytometry. A whole-blood count was performed in addition. Two groups of patients were examined, paranoid-type and residual-type schizophrenics. The numbers of both monocytes and neutrophils, but not of lymphocytes, were increased significantly in the schizophrenic sample. The IFN-gamma production of the schizophrenics as a whole group, and of the paranoid patients, was reduced significantly in comparison with the control group (p < or = 0.05). The residual patients produced less IFN-gamma than the controls, but more than the paranoid patients. The latter differences did not reach statistical significance. The production of IL-4, which physiologically antagonizes the production of IFN-gamma, was not significantly higher in the patient group. No changes in the lymphocyte subpopulations were observed. The production of IL-2 showed a trend toward reduction in paranoid patients, but not in residual schizophrenics. The serum sIL-2R levels were elevated slightly in schizophrenics when compared with controls. In order to rule out a possible effect of cortisol on cytokine production, 20 schizophrenics were compared with 20 age- and gender-matched controls. However, neither elevated cortisol levels were detected in the schizophrenic sample, nor significant intercorrelations between cortisol levels and cytokine production, or levels of sIL-2R, respectively. In summary, our data reinforce the possibility of immune dysfunction in schizophrenia and point to the possible relevance of disease subgroups in this respect.

Production of interferons and lymphokines in leukocyte cultures of patients with schizophrenia.

Recently, several lines of evidence have suggested the possible of immunological dysfunction in the pathogenesis of schizophrenia. We therefore investigated the ability to produce interferons and lymphokines in response to mitogenic or viral stimulation in a whole blood assay of 37 schizophrenic patients (DSM-III-R) and of 42 healthy blood donors. Phytohaemagglutinin (PHA) was used for the induction of interleukin-2 (IL-2), interferon gamma (INF gamma), interleukin-6 (IL-6) and the soluble interleukin-2 receptor (sIL-2R) and Newcastle Disease Virus (NDV) for the induction of interferon alpha 2 (INF alpha 2). All lymphokines and, in addition, the sIL-2R in the sera were determined by ELISA technique. The psychopathological status of the patients was assessed by psychiatrists according to internationally accepted standards. The patient group showed a trend to lower levels of the interferons alpha 2 and gamma and a significant decrease of IL-2 production. The sIL-2R levels were significantly increased in the sera of schizophrenic patients. The latter increase was associated with a poor assessment of prognosis (Strauss and Carpenter). This association appears to be of interest. However, its significance is not understood, since longitudinal studies could not be performed.