Comparative analysis of cytokine patterns in immunological, infectious, and oncological neurological disorders

Cytokines and chemokines in patients with chronic inflammatory demyelinating polyradiculoneuropathy and multifocal motor neuropathy: A systematic review

Advances in the understanding of cytokines have revolutionized mechanistic treatments for chronic inflammatory and autoimmune diseases, as exemplified by rheumatoid arthritis. We conducted a systematic literature review on the role of cytokines and chemokines in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and multifocal motor neuropathy (MMN). Ovid Medline, EMBASE and Web of Science were searched until August 31, 2022 for human studies investigating cytokines levels in CIDP or MMN. Fifty-five articles on 1061 CIDP patients and 86 MMN patients were included, with a median of 18 patients per study (range 3-71). Studies differed in the inclusion criteria, type of assay, manufacturer, control subjects, and tested biological material. Only a minority of studies reported data on disease activity. Interleukin (IL)-6, IL-17, CXCL10, and tumor necrosis factor alpha (TNF-α), were elevated in CIDP compared to controls in most of the studies. IL-6 and TNF-α levels are also correlated with disability. In MMN patients, IL-1Ra was elevated in the majority of the reports. While acknowledging the challenges in comparing studies and the various limitations of the studies, including small patient numbers, particularly in MMN, our review suggests that IL-6, IL-17, CXCL10, and TNF-α might play a role in CIDP pathogenesis. Larger studies are needed in MMN.

Characteristic cerebrospinal fluid findings in immune checkpoint inhibitor-related peripheral neuropathy: A case report

Although immune checkpoint inhibitors (ICIs) are widely used to treat unresectable malignant tumors, they can cause undesirable side effects called immune-related adverse events, including neurological toxicities. Here, we describe a case of ICI-related peripheral neuropathy (irPN) with characteristic cerebrospinal fluid (CSF) findings. In addition to pleocytosis and increased protein levels, the present case showed increased levels of CSF soluble interleukin-2 receptor (sIL-2R), IL-6, and IL-10, suggesting activated T cell-related autoimmunity. We believe that CSF cytokines and sIL-2R could be novel biomarkers of irPN.

Glioma and Neurokinin-1 Receptor Antagonists: A New Therapeutic Approach

BACKGROUND

In adults, the most lethal and frequent primary brain tumor is glioblastoma. Despite multimodal aggressive therapies, the median survival time after diagnosis is around 15 months. In part, this is due to the blood-brain barrier that restricts common treatments (e.g., chemotherapy). Unfortunately, glioma recurs in 90% of patients. New therapeutic strategies against glioma are urgently required. Substance P (SP), through the neurokinin (NK)-1 receptor, controls cancer cell proliferation by activating c-myc, mitogenactivated protein kinases, activator protein 1 and extracellular signal-regulated kinases 1 and 2. Glioma cells overexpress NK-1 receptors when compared with normal cells. The NK-1 receptor/SP system regulates the proliferation/migration of glioma cells and stimulates angiogenesis, triggering inflammation which contributes to glioma progression. In glioma cells, SP favors glycogen breakdown, essential for glycolysis. By contrast, in glioma, NK-1 receptor antagonists block the proliferation of tumor cells and the breakdown of glycogen and also promote the death (apoptosis) of these cells. These antagonists also inhibit angiogenesis and exert antimetastatic and anti-inflammatory actions.

OBJECTIVE

This review updates the involvement of the NK-1 receptor/SP system in the development of glioma and the potential clinical application of NK-1 receptor antagonists as antiglioma agents.

CONCLUSION

The NK-1 receptor plays a crucial role in glioma and NK-1 receptor antagonists could be used as anti-glioma drugs.

Reduced soluble RAGE is associated with disease severity of axonal Guillain-Barré syndrome

Soluble receptor for advanced glycation end products (sRAGE) is an anti-inflammatory factor that mitigates the proinflammatory effects of high mobility group box 1 (HMGB1). The aim of this study was to investigate whether Guillain-Barré syndrome (GBS)-related inflammation are mediated by sRAGE and HMGB1. We measured serum sRAGE, HMGB1, IL-6, and TNF-α levels in 86 patients with GBS and analysed associations between sRAGE or HMGB1 and clinical variables in these subjects. In addition, we determined cerebrospinal fluid sRAGE and HMGB1 levels in a cross-sectional study of 50 patients with GBS who had matched serum samples. We found serum sRAGE levels in patients with the acute motor axonal neuropathy (AMAN) subtype of GBS, but not other subtypes, were significantly lower than those in healthy controls, and were significantly correlated with GBS disability score and Erasmus GBS outcome score, while serum HMGB1, IL-6, and TNF-α levels in all subtypes of GBS were significantly higher than those in healthy controls. Moreover, increased sRAGE levels and decreased HMGB1 levels after treatment were observed. Our results showed that serum sRAGE may be a useful biomarker for inflammation in the AMAN GBS subtype, while HMGB1 may be related to the inflammatory process across all types of GBS.

The prognostic significance of serum and cerebrospinal fluid MMP-9, CCL2 and sVCAM-1 in leukemia CNS metastasis

Metastasis to the central nervous system (CNS) is the primary obstacle in leukemia treatment. Matrix metalloproteinase-9 (MMP-9), chemokine ligand-2 (CCL2) and soluble vascular adhesion molecule-1 (sVCAM-1) play crucial roles in tumor cell adhesion, motivation and survival, but their roles in leukemia CNS metastasis remain to be elucidated. We investigated the prognostic significance of serum and cerebrospinal fluid (CSF) MMP-9, CCL2 and sVCAM-1 in leukemia patients to explore their potential as predictive biomarkers of the development of CNS leukemia (CNSL). MMP-9, CCL2 and sVCAM-1 were measured in paired CSF and serum samples collecting from 33 leukemia patients with or without CNS metastasis. Other risk factors related to CNSL prognosis were also analyzed. sVCAM-1Serum and CCL2Serum/CSF were significantly higher in the CNSL group than in the non-CNSL group and the controls (p < 0.05). MMP-9Serum was insignificantly lower in the CNSL group than in the non-CNSL group and the controls (p > 0.05). No differences were found for the sVCAM-1Serum, CCL2Serum, and MMP-9Serum levels between non-CNSL patients and controls (p > 0.05). MMP-9CSF was significantly higher in the CNSL group than both the non-CNSL and the control groups (p < 0.05). The indexes of sVCAM-1, CCL2, and MMP-9 in the CNSL group were lower than in the controls (p < 0.05). Positive correlations were determined between the MMP-9CSF and the ALBCSF/BBB value/WBCCSF, between sVCAM-1Serum and the WBCCSF/BBB value. Negative correlations existed between MMP-9Serum and the ALBCSF/BBB value/WBCCSF, and between the CCL2 index and ALBCSF. sVCAM-1Serum was positively associated with event-free survival (EFS), and patients with higher levels of ALBCSF, MMP-9CSF/Serum, CCL2CSF/Serum, and sVCAM-1CSF/Serum had shorter EFS. MMP-9CSF, CCL2CSF and sVCAM-1CSF are the first three principal components analyzed by cluster and principal component analysis. Our data suggest that MMP-9, CCL2 and sVCAM-1 in the CSF may be more potent than serum in predicting the possibility of leukemia metastatic CNS and the outcome of CNSL patients.

Modeling toxicodynamic effects of trichloroethylene on liver in mouse model of autoimmune hepatitis

Chronic exposure to industrial solvent and water pollutant trichloroethylene (TCE) in female MRL+/+mice generates disease similar to human autoimmune hepatitis. The current study was initiated to investigate why TCE-induced autoimmunity targeted the liver. Compared to other tissues the liver has an unusually robust capacity for repair and regeneration. This investigation examined both time-dependent and dose-dependent effects of TCE on hepatoprotective and pro-inflammatory events in liver and macrophages from female MRL+/+mice. After a 12-week exposure to TCE in drinking water a dose-dependent decrease in macrophage production of IL-6 at both the transcriptional and protein level was observed. A longitudinal study similarly showed that TCE inhibited macrophage IL-6 production. In terms of the liver, TCE had little effect on expression of pro-inflammatory genes (Tnfa, Saa2 or Cscl1) until the end of the 40-week exposure. Instead, TCE suppressed hepatic expression of genes involved in IL-6 signaling (Il6r, gp130, and Egr1). Linear regression analysis confirmed liver histopathology in the TCE-treated mice correlated with decreased expression of Il6r. A toxicodynamic model was developed to estimate the effects of TCE on IL-6 signaling and liver pathology under different levels of exposure and rates of repair. This study underlined the importance of longitudinal studies in mechanistic evaluations of immuntoxicants. It showed that later-occurring liver pathology caused by TCE was associated with early suppression of hepatoprotection rather than an increase in conventional pro-inflammatory events. This information was used to create a novel toxicodynamic model of IL-6-mediated TCE-induced liver inflammation.

Intravenous immunoglobulin preparation attenuates neurological signs in rat experimental autoimmune neuritis with the suppression of macrophage inflammatory protein -1α expression

To clarify the mechanism of action of an intravenous immunoglobulin (IVIG) preparation in chronic inflammatory demyelinating polyneuropathy, the effects of IVIG were investigated using an experimental autoimmune neuropathy model in the rat. IVIG significantly suppressed the progression of neurologic signs and sciatic nerve conduction velocity with the inhibition of inflammatory cell infiltration, mainly of macrophages, to the peripheral nerves. A significant suppressive effect on the expression of macrophage inflammatory protein 1-α (MIP-1α) was simultaneously observed in the nerves. These results suggest that IVIG is effective for inflammatory demyelinating polyneuropathy by inhibiting the chemotactic factor of macrophages.

Diagnostic strategies to investigate cerebrospinal fluid involvement in haematological malignancies

Central nervous system (CNS) involvement is a fatal complication of certain haematological malignancies with an incidence as high as 25% in specific leukaemia/lymphoma subtypes. It is often accompanied by 'occult' cerebrospinal fluid (CSF) involvement at diagnosis, which is frequently missed by conventional cytology examination. Unfortunately, a diagnostic gold standard is yet unavailable since CSF morphology may be negative for malignant cells in up to 45% of patients with suspected meningeal involvement. New technologies such as flow cytometry, molecular genetics and newer biomarkers may improve sensitivity and specificity facilitating the diagnosis of CNS involvement as well as effective prophylaxis and successful treatment.

Viral and inflammatory triggers of neurodegenerative diseases

Here, we synthesize research behind the emerging hypothesis that inflammation--which can result, for example, from viral infections--can initiate and propagate chronic neuronal dysfunction, an event that precedes the clinical onset of many neurodegenerative diseases. Therapeutic approaches that target immunological pathways in the prodromal phase of diseases might decrease the incidence of neurodegenerative disorders and increase the therapeutic window for neuroprotection.

Identification of gene networks and pathways associated with Guillain-Barré syndrome

BACKGROUND

The underlying change of gene network expression of Guillain-Barré syndrome (GBS) remains elusive. We sought to identify GBS-associated gene networks and signaling pathways by analyzing the transcriptional profile of leukocytes in the patients with GBS.

METHODS AND FINDINGS

Quantitative global gene expression microarray analysis of peripheral blood leukocytes was performed on 7 patients with GBS and 7 healthy controls. Gene expression profiles were compared between patients and controls after standardization. The set of genes that significantly correlated with GBS was further analyzed by Ingenuity Pathways Analyses. 256 genes and 18 gene networks were significantly associated with GBS (fold change ≥2, P<0.05). FOS, PTGS2, HMGB2 and MMP9 are the top four of 246 significantly up-regulated genes. The most significant disease and altered biological function genes associated with GBS were those involved in inflammatory response, infectious disease, and respiratory disease. Cell death, cellular development and cellular movement were the top significant molecular and cellular functions involved in GBS. Hematological system development and function, immune cell trafficking and organismal survival were the most significant GBS-associated function in physiological development and system category. Several hub genes, such as MMP9, PTGS2 and CREB1 were identified in the associated gene networks. Canonical pathway analysis showed that GnRH, corticotrophin-releasing hormone and ERK/MAPK signaling were the most significant pathways in the up-regulated gene set in GBS.

CONCLUSIONS

This study reveals the gene networks and canonical pathways associated with GBS. These data provide not only networks between the genes for understanding the pathogenic properties of GBS but also map significant pathways for the future development of novel therapeutic strategies.

The Toll-like receptor-3 agonist polyinosinic:polycytidylic acid triggers nigrostriatal dopaminergic degeneration

In Parkinson's disease (PD), loss of striatal dopaminergic (DA) terminals and degeneration of DA neurons in the substantia nigra (SN) are associated with glial reactions. Such inflammatory processes are commonly considered an epiphenomenon of neuronal degeneration. However, there is increasing recognition of the role of neuroinflammation as an initiation factor of DA neuron degeneration. To investigate this issue, we established a new model of brain inflammation by injecting the Toll-like receptor 3 (TLR-3) agonist polyinosinic:polycytidylic acid [poly(I:C)] in the SN of adult rats. Poly(I:C) injection induced a sustained inflammatory reaction in the SN and in the dorsolateral striatum. Significant changes were detected in proteins relevant to synaptic transmission and axonal transport. In addition, cytoplasmic mislocalization of neuronal TAR DNA binding protein TDP-43 was observed. Poly(I:C) injection increased the susceptibility of midbrain DA neurons to a subsequent neurotoxic trigger (low-dose 6-hydroxydopamine). Systemic delivery of interleukin-1 receptor antagonist protected SN DA neurons exposed to combined poly(I:C) induced inflammatory and neurotoxic oxidative stress. These data indicate that viral-like neuroinflammation induces predegenerative changes in the DA system, which lowers the set point toward neuronal dysfunction and degeneration. New powerful neuroprotective therapies for PD might be considered by targeting critical inflammatory mechanisms, including cytokine-induced neurotoxicity.

The role of cytokines in Guillain-Barré syndrome

Cytokines play an important role in the pathogenesis of autoimmune diseases including Guillain-Barré syndrome (GBS) and its animal model experimental autoimmune neuritis (EAN). In this article, we reviewed the current knowledge of the role of cytokines such as TNF-α, IFN-γ, IL-1β, IL-6, IL-12, IL-18, IL-23, IL-17, IL-10, IL-4 and chemokines in GBS and EAN as unraveled by studies both in the clinic and the laboratory. However, these studies occasionally yield conflicting results, highlighting the complex role that cytokines play in the disease process. Efforts to modulate cytokine function in GBS and other autoimmune disease have shown efficiency indicating that cytokines are important therapeutic targets.

Rit signaling contributes to interferon-gamma-induced dendritic retraction via p38 mitogen-activated protein kinase activation

The proinflammatory cytokine interferon-gamma (IFNgamma) alters neuronal connectivity via selective regressive effects on dendrites but the signaling pathways that mediate this effect are poorly understood. We recently demonstrated that signaling by Rit, a member of the Ras family of GTPases, modulates dendritic growth in primary cultures of sympathetic and hippocampal neurons. In this study, we investigated a role for Rit signaling in IFNgamma-induced dendritic retraction. Expression of a dominant negative Rit mutant inhibited IFNgamma-induced dendritic retraction in cultured embryonic rat sympathetic and hippocampal neurons. In pheochromacytoma cells and hippocampal neurons, IFNgamma caused rapid Rit activation as indicated by increased GTP binding to Rit. Silencing of Rit by RNA interference suppressed IFNgamma-elicited activation of p38 MAPK in pheochromacytoma cells, and pharmacological inhibition of p38 MAPK significantly attenuated the dendrite-inhibiting effects of IFNgamma in cultured sympathetic and hippocampal neurons without altering signal transducer and activator of transcription 1 activation. These observations identify Rit as a downstream target of IFNgamma and suggest that a novel IFNgamma-Rit-p38 signaling pathway contributes to dendritic retraction and may, therefore, represent a potential therapeutic target in diseases with a significant neuroinflammatory component.

Comparative analysis of cytokine gene expression in cerebrospinal fluid of horses without neurologic signs or with selected neurologic disorders

OBJECTIVE

To determine gene transcription for cytokines in nucleated cells in CSF of horses without neurologic signs or with cervical stenotic myelopathy (CSM), West Nile virus (WNV) encephalitis, equine protozoal myeloencephalitis (EPM), or spinal cord trauma.

ANIMALS

41 horses (no neurologic signs [n = 12], CSM [8], WNV encephalitis [9], EPM [6], and spinal cord trauma [6]).

PROCEDURES

Total RNA was extracted from nucleated cells and converted into cDNA. Gene expression was measured by use of real-time PCR assay and final quantitation via the comparative threshold cycle method.

RESULTS

Cytokine genes expressed by nucleated cells of horses without neurologic signs comprised a balance between proinflammatory tumor necrosis factor-alpha (TNF-alpha), anti-inflammatory cytokines (interleukin [IL]-10 and transforming growth factor [TGF]-beta), and Th1 mediators (interferon [IFN]-gamma). Cells of horses with CSM mainly expressed genes for TNF-alpha, TGF-beta, and IL-10. Cells of horses with WNV encephalitis mainly expressed genes for IL-6 and TGF-beta. Cells of horses with EPM mainly had expression of genes for IL-6, IL-8, IL-10, TNF-alpha, IFN-gamma, and TGF-beta. Cells from horses with spinal cord trauma had expression mainly for IL-6; IFN-gamma; TGF-beta; and less frequently, IL-2, IL-10, and TNF-alpha. Interleukin-8 gene expression was only detected in CSF of horses with infectious diseases.

CONCLUSIONS AND CLINICAL RELEVANCE

Despite the small number of CSF samples for each group, results suggest distinct gene signatures expressed by nucleated cells in the CSF of horses without neurologic signs versus horses with inflammatory or traumatic neurologic disorders.

Investigation of possible cytokine induction in peripheral blood mononuclear cells by heat-stable serotypes of Campylobacter jejuni

Several Campylobacter jejuni heat-stable (HS) serotypes have been associated with the autoimmune Guillain-Barre neurological syndrome (GBS). In order to examine the possible involvement of cytokines in this phenomenon, the levels of three pro-inflammatory cytokines (interleukin (IL)-2sRa, IL-6 and interferon (IFN)-gamma) and one anti-inflammatory cytokine (IL-10) were measured in peripheral blood mononuclear cells after induction by different C. jejuni serotypes. No differences were found for IL-6, IFN-gamma and IL-10, but the non-sialylated serotype HS:3 was associated with decreased production of IL-2sRa. The results raise the possibility that absence of sialylation might be associated with the inability to induce inflammatory factors such as cytokines.

Soluble interleukin-6 receptor (sIL-6R) in cerebrospinal fluid of patients with inflammatory and non inflammatory neurological diseases

IL-6 acts on target cells via the ligand-binding protein interleukin-6 receptor (IL-6R) and the affinity-converting and signal-transducing glycoprotein 130 (gp130). Soluble interleukin-6 receptor (sIL-6R) has an agonistic role because the soluble complex (IL-6/sIL-6R) can activate cells that do not express IL-6R and an antagonistic role as it enhances the inhibitory activity of sgp130. Soluble forms of both receptors, sIL-6R and sgp130, regulate the action of IL-6. sIL-6R was measured by a sensitive enzyme-linked immunosorbent assay in paired sera and cerebrospinal fluid (CSF) from 46 patients with inflammatory neurological diseases (IND), 45 patients with relapsing-remitting multiple sclerosis (RR-MS), 13 patients with primary progressive multiple sclerosis (PP-MS), 17 patients with other non inflammatory neurological diseases (NIND) and 13 mentally healthy individuals--healthy controls (HC). Patients with RR-MS had CSF sIL-6R levels comparable to those from patients with IND, but higher than patients with NIND and HC. A positive correlation between the CSF/serum albumin (QAlb) and CSF sIL-6R levels was observed in IND but not in RR-MS patients indicating that CSF sIL-6R levels in IND patients could be influenced by serum sIL-6R and blood brain barrier (BBB) permeability properties. RR-MS patients had higher values of [CSF/serum sIL-6R:CSF/serum albumin] (sIL-6R index) than IND patients suggesting that in multiple sclerosis (MS), the increase in CSF sIL-6R could be due to intrathecal synthesis of sIL-6R. The finding of increased CSF sIL-6R concentrations (>979 pg/ml) with sIL-6R index (>4.66), in correlation with positive oligoclonal bands in RR-MS patients, suggests that values of sIL-6R index > 4.66 indicate intrathecal increase of sIL-6R and might be used as an indicator of neuroimmunoregulatory and inflammatory processes in the central nervous system (CNS).

Proinflammatory cytokine reactions in enterovirus 71 infections of the central nervous system

Enterovirus 71 (EV71) infection can lead to devastating clinical outcomes. An appreciation of the scientific relationship between cytokine response and patient mortality may help limit the risks posed by this deadly illness. We present the results of a study that compared the cerebrospinal fluid (CSF) and serum levels of interleukin-6 (IL-6) and interleukin-1beta (IL-1beta) in 24 patients with EV71 infection. Cases in this study involved diverse manifestations or complications, including encephalitis, poliomyelitis-like syndrome, meningitis, and pulmonary edema. CSF levels of IL-6 in study patients were found to be consistently higher during the first 2 days of central nervous system (CNS) involvement than afterward. Compared with patients who did not have pulmonary edema, patients who experienced pulmonary edema had dramatically varied blood values, including IL-6, white blood cell counts, and glucose levels. Our findings suggest that the combination of CNS and systemic inflammatory response may trigger EV71-related cardiopulmonary collapse.

Interferon gamma induces retrograde dendritic retraction and inhibits synapse formation

The expression of interferon gamma (IFNgamma) increases after neural injury, and it is sustained in chronic inflammatory conditions such as multiple sclerosis and infection with human immunodeficiency virus. To understand how exposure to this proinflammatory cytokine might affect neural function, we examined its effects on cultures of neurons derived from the central and peripheral nervous systems. IFNgamma inhibits initial dendritic outgrowth in cultures of embryonic rat sympathetic and hippocampal neurons, and this inhibitory effect on process growth is associated with a decrease in the rate of synapse formation. In addition, in older cultures of sympathetic neurons, IFNgamma also selectively induces retraction of existing dendrites, ultimately leading to an 88% decrease in the size of the arbor. Dendritic retraction induced by IFNgamma represents a specific cellular response because it occurs without affecting axonal outgrowth or cell survival, and it is not observed with tumor necrosis factor alpha or other inflammatory cytokines. IFNgamma-induced dendritic retraction is associated with the phosphorylation and nuclear translocation of signal transducer and activator of transcription 1 (STAT1), and expression of a dominant-negative STAT1 construct attenuates the inhibitory effect of IFNgamma. Moreover, retrograde dendritic retraction is observed when distal axons are selectively exposed to IFNgamma. These data imply that IFNgamma-mediated STAT1 activation induces both dendritic atrophy and synaptic loss and that this occurs both at the sites of IFNgamma release and at remote loci. Regressive actions of IFNgamma on dendrites may contribute to the neuropathology of inflammatory diseases.

Changes in the immunologic phenotype of human malignant glioma cells after passaging in vitro

Although immunotherapeutic strategies against glioblastomas have been promising both in vitro and in animal models, similar successes have not been realized in human clinical trials. One reason may be that immunotherapeutic strategies are based on prior studies that primarily have used human glioblastoma cell lines passaged in vitro, which may not accurately reflect the in vivo properties of glioblastoma cells. In this report, we used flow cytometry to quantify the expression of immunological cell surface molecules on human glioblastomas directly ex vivo (prior to any in vitro culturing) and after varying passages in vitro. Furthermore, we used ELISA to quantitate cytokine secretion after various passages in vitro. We demonstrate that in vitro culturing of established cell lines led to increases in the cell surface expression of MHC class I and ICAM-1 and secretion of IL-6 and TGF-beta(2). Furthermore, there were significant changes in the expression of MHC class I, MHC class II, B7-2, ICAM-1, and FasL when comparing ex vivo tumor cells to those after a single passage in vitro. After passaging once in vitro, there were also significant changes in the secretion of TGF-beta(2) and IL-10. This report indicates that in vitro culturing leads to significant changes in both cell surface molecules and secreted cytokines, which are known to affect the ability of immune cells to initiate an anti-tumor immune response. These changes in the immunological phenotype of glioblastomas after in vitro culturing may in part explain the limited success of immunotherapeutic strategies against glioblastomas in human clinical trials.

Increased serum tumor necrosis factor alpha concentrations in major depression and multiple sclerosis

There is now evidence that major depression is accompanied by activation of the inflammatory response system (IRS) as indicated by an increased production of pro-inflammatory cytokines. There is circumstantial evidence implicating pro-inflammatory cytokines, such as tumor necrosis factor-alpha (TNFalpha) in the pathogenesis of multiple sclerosis (MS). The aims of the present study were to examine (i) the serum concentrations of interleukin-6 (IL-6), IL-8, TNFalpha, IL-2 receptor (IL-2R) and CC16 (uteroglobulin), an endogenous anti-cytokine, in depressed and MS patients compared to normal controls, and (ii) the effects of treatment with antidepressants on the above IRS variables in depressed patients. Serum TNFalpha was significantly higher in depressed and MS patients than in normal controls. Serum IL-8 was significantly higher in depressed patients than in patients with MS. Serum CC16 was significantly higher in patients with MS than in normal controls and depressed patients. Nonresponders to treatment with antidepressants had significantly higher serum IL-2R and lower serum CC16 concentrations than responders to treatment. The results show that (i) depression is accompanied by activation of the IRS and that this activation is more pronounced in depression than in MS, and (ii) IRS activation in depressed patients is related to a nonresponse to treatment with antidepressants.

T-cell interleukin-6 receptor binding in interferon-beta-1b-treated multiple sclerosis patients

Multiple sclerosis (MS) is a T-cell-mediated autoimmune demyelinating disease of the central nervous system, associated with an altered cytokine network. We previously assayed peripheral blood T-lymphocyte binding for two prototypic cytokines, tumour necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6), and found that T cells from MS patients had significantly more TNF-alpha and IL-6 receptors than those from healthy controls. In the present work, paralleling a previous one on T-cell TNF-alpha binding, we studied the effect of interferon (IFN)-beta-1b treatment on T-lymphocyte IL-6 binding in patients with relapsing-remitting MS. T cells from MS patients had significantly (P < 0.001) higher amounts of IL-6 receptors than those from controls [292 +/- 6 vs. 228 +/- 8 (mean +/- SEM) receptors per cell, respectively], whereas the ligand-receptor affinity values were similar in the two groups [26.2 +/- 0.7 and 25.7 +/- 0.4 (mean +/- SEM) pmoles/l, respectively]. After a 3-month IFN-beta-1b treatment, they showed a significant decrease in IL-6 binding [266 +/- 7 (mean +/- SEM) receptors per cell]. After 6 and 9 months, T-cell IL-6 B(max) values were even lower [258 +/- 8 and 251 +/- 8 (mean +/- SEM) receptors per cell]. Since an increased IL-6 binding might be linked to a lymphocyte activation, our data give further support for an enhanced immune response in patients with MS. Our data seem to demonstrate that the major effects of IFN-beta-1b treatment result in a decrease of T-cell activation.

Expression of TNFalpha and TGFbeta1 in Guillain-Barré syndrome: correlation of a low TNFalpha-/TGFbeta1-mRNA ratio with good recovery and signs for immunoregulation within the cerebrospinal fluid compartment

In the pathogenesis of Guillain-Barré syndrome (GBS) a dysregulation of cytokines is supposed. The protein concentration and mRNA expression of TNFalpha and TGFbeta1 were investigated in cerebrospinal fluid (CSF) and blood in 10 patients with GBS. TNFalpha-mRNA was increased at the beginning of the disease and demonstrated a decline during the time course (P = 0.001). The level of TNFalpha protein was elevated in only a few patients. TGFbeta1-mRNA (P = 0.001) and the active TGFbeta1 protein (P < 0.05) increased during the course of GBS, and the level of total TGFbeta1 protein was temporarily elevated (P = 0.005). A low ratio of TNFalpha-/TGFbeta-mRNA expression correlated to a good clinical course (P < 0.05). The results indicate an association of TNFalpha with disease activity. TGFbeta1 seems to terminate and limit the inflammatory reactions and to promote the healing course of GBS. In addition the investigations show that in GBS immunoregulatory mechanisms also take place in the CSF compartment itself and that CSF cells are involved in the production of pro-inflammatory as well as immunosuppressive cytokines.

Local effects of recombinant rat interleukin-6 on the peripheral nervous system

Interleukin-6 (IL-6) is a multifunctional cytokine with a broad range of activities and can affect a variety of target cells or systems in multiple ways. However, there is currently no consensus on how IL-6 directly affects the peripheral nervous tissue. We performed histopathological and immunohistochemical analyses to investigate the direct effects of recombinant rat IL-6 (rrIL-6) following its intraneural injection into the sciatic nerve of adult Lewis rats. One day after injection, a large number of macrophages, major histocompatibility complex (MHC) class II positive cells, and CD4+ and CD8+ T cells appeared within the perineurium and endoneurium. From day 4 to day 7 after injection, we observed a gradual increase of inflammation and demyelination. On day 7, demyelination affected more than 80% of nerve fibres. In contrast, in the sterile phosphate-buffered saline (PBS)-injected control group, lower inflammation and fewer demyelinating nerve fibres were observed on days 4 and 7. Thus, intraneural injection of rrIL-6 into the sciatic nerve induces high inflammation and severe demyelination. This study improves our understanding of the effector mechanisms underlying inflammation and demyelination and identifies IL-6 as an essential mediator of inflammation and demyelination in the peripheral nervous system after local administration.

Interferon-gamma preferentially reduces memory/effector CD8 T lymphocytes in healthy subjects

To evaluate the influence of interferon-gamma (IFN-gamma) on leukocyte dynamics, with a focus on naive and memory T cells, we studied 6 healthy subjects twice in a placebo-controlled trial: once after the administration of recombinant human IFN-gamma (rhIFN-gamma; 100 microg/m2 subcutaneously) and at least 4 weeks later, after the administration of saline solution. Additionally, we studied the expression of adhesion molecules on T lymphocytes after in vitro incubation of whole blood with rhIFN-gamma. IFN-gamma induced a significant depletion in the number of T lymphocytes (P < .05 vs control), which was more severe in the CD8+ cell subset than in the CD4+ T cell subset. The numbers of naive CD4+ T cells and memory CD4+ T cells were equally affected by IFN-gamma, whereas within the CD8+ T cell subset, memory/effector cells disappeared preferentially as compared with naive cells (P < .05 vs control). In addition, IFN-gamma induced a decrease in B cells, NK cells, and monocytes. After an initial increase, granulocyte counts decreased significantly as compared with controls. These effects appeared not to be caused by the minimal rise in plasma cortisol levels (P < .05 vs control). In vitro, IFN-gamma did not up-regulate the expression of CD11a, NKI L16, CD11b, LFA-3, or VLA-4. We conclude that the administration of a single dose of IFN-gamma to healthy subjects profoundly affects the numbers of several leukocyte subsets in the peripheral blood compartment.

Suppression of chronic experimental autoimmune neuritis by nasally administered recombinant rat interleukin-6

Experimental autoimmune neuritis (EAN) is a CD4+ T-cell-mediated demyelinating disease of the peripheral nervous system (PNS) and serves as experimental model for human immune-demyelinating neurophathies, especially the Guillain-Barré syndrome. In this study, we examined the effect of recombinant rat interleukin-6 (rrIL-6) on chronic EAN in Lewis rats induced by immunization with P2 peptide 57-81 and Freund's complete adjuvant (FCA). Nasal administration of rat rIL-6 (1 microg/rat/day) beginning in the initial phase of EAN as a therapeutic agent, decreased the severity and the duration of clinical EAN. Low-grade inflammation and suppression of regional demyelination within the sciatic nerves were seen in rrIL-6-treated rats. Hyporesponsiveness of lymph node T cells, down-regulation of serum tumour necrosis factor-alpha (TNF-alpha) and increased levels of P2-specific immunoglobulin G1 (IgG1) antibodies document that nasal administration of rrIL-6 was effective systemically. However, because of the non-specific nature of the treatment and multiple effects of IL-6, more experience and great caution are needed, before nasal administration of IL-6 can be considered as a treatment of human autoimmune demyelinating neurophathies.

Interferon-gamma has immunomodulatory effects with minor endocrine and metabolic effects in humans

To evaluate whether interferon-gamma (IFN-gamma) is involved in the interaction between the immune and endocrine systems in vivo, we studied six healthy subjects twice in a placebo-controlled trial: once after administration of recombinant human IFN-gamma and, on another occasion, after administration of saline. The rate of appearance of glucose was determined by infusion of [6,6-2H2]glucose and resting energy expenditure by indirect calorimetry. Human leukocyte antigen-DR gene expression on monocytes and serum neopterin increased after administration of IFN-gamma (P < 0.05 vs. control). IFN-gamma increased serum interleukin-6 levels significantly. Levels of tumor necrosis factor-alpha remained below detection limits. IFN-gamma increased plasma concentrations of ACTH and cortisol (P < 0.05 vs. control), IFN-gamma did not alter concentrations of growth hormone, (nor)epinephrine, insulin, C peptide, glucagon, or insulin-like growth factor I. IFN-gamma did not alter plasma concentrations of glucose and free fatty acids nor the rate of appearance of glucose. IFN-gamma increased resting energy expenditure significantly. We conclude that IFN-gamma is a minor stimulator of the endocrine and metabolic pathways. Therefore, IFN-gamma by itself is probably not a major mediator in the interaction between the immune and the endocrine and metabolic systems.

Substance P activates responses correlated with tumour growth in human glioma cell lines bearing tachykinin NK1 receptors

The neuropeptide substance P (SP), by stimulating tachykinin NK1 receptors (NK1R), triggers a number of biological responses in human glioma cells which are potentially relevant for tumour growth. First, radioligand binding studies demonstrated the presence of tachykinin NK1R on SNB-19, DBTRG-05 MG and U373 MG, but not on U138 MG and MOG-G-GCM human glioma cell lines. Second, application of SP or neurokinin A (NKA) to NK1R+ glioma cell lines increased the secretion of interleukin 6 (IL-6) and potentiated IL-6 secretion induced by IL-1beta. SP also up-regulated the release of transforming growth factor beta1 (TGF-beta1) by the U373 MG glioma cell line. Third, SP induced new DNA synthesis and enhanced the proliferation rate of NK1R+, but not of NK1R- glioma cell lines. Also, NKA stimulated the proliferation and cytokine secretion in NK1R+ glioma cell lines. All the stimulant effects of SP/NKA on NK1R+ glioma cell lines were completely blocked by a specific tachykinin NK1R antagonist, MEN 11467. These data support the potential use of tachykinin NK1R antagonist for controlling the proliferative rate of human gliomas.

Peripheral nerve fibroblasts as a source of IL-6, TNFalpha and IL-1 and their modulation by IFNgamma

Interleukin-6 (IL-6), tumor necrosis factor alpha (TNFalpha), and interleukin-1 (IL-1) are immunomodulatory cytokines produced by Schwann cells of the peripheral nervous system (PNS). Their upregulation has been associated with autoimmune inflammatory diseases of the PNS such as Guillain-Barré Syndrome (GBS) and Chronic Inflammatory Demyelinating Neuropathy (CIDP). We now report that PNS fibroblasts and a PNS fibroblast cell line - MA-1 express mRNA for IL-6, TNFalpha and IL-I and that the MA-1 cell line secretes these molecules. Flow cytometry and fluorescent activated cell sorting defined that 76% of MA-1 fibroblasts were Thy1.1+ and 24% were Thy1.1-. Each subset expressed major histocompatibility class (MHC) I molecules and intercellular adhesion molecule-1 (ICAM-1). IFNgamma stimulation induced the expression of MHC II molecules in Thy1.1+, but not Thy1.1(-) cells. All MA-1 cells expressed mRNA for IL-6, TNFalpha, and IL-1 plus or minus IFNgamma stimulation. IFNgamma stimulation significantly reduced the production of IL-6 but increased TNFalpha production. Direct in situ reverse-transcriptase polymerase chain reaction (RT-PCR) showed that IL-1 mRNA staining increased significantly following IFNgamma stimulation. These results provide evidence for the first time that not only Schwann cells, but also peripheral nerve fibroblasts are a source of immunomodulatory cytokines within the PNS and may contribute to inflammatory processes in PNS disease.

Elevated serum levels of IFN-gamma, IL-4 and TNF-alpha/unelevated serum levels of IL-10 in patients with demyelinating diseases during the acute stage

We investigated IFN-gamma, IL-4, IL-10 and TNF-alpha in the sera of 42 patients with demyelinating diseases: multiple sclerosis (MS) (21), Guillain-Barré syndrome (GBS) (14), Miller-Fisher syndrome (MFS) (7) during the acute or active stage and 12 normal controls using an originally devised sensitive sandwich enzyme-linked immunosorbent assay (ELISA). We found elevated serum levels of IFN-gamma derived from T helper 1 (Th1) cells and of IL-4 derived from Th2 cells in MS, GBS and MFS. It has been reported in several studies that IL-4 production is increased in MS; however, there have been no reports of elevated serum IL-4 levels in MS. We here describe elevated serum levels of IL-4 in MS, GBS and MFS for the first time. Serum TNF-alpha levels were significantly elevated in patients with MS (p < 0.01). Serum TNF-alpha levels also tended to be elevated in patients with GBS and MFS, but not significantly elevated compared with those of controls. Serum IL-10 levels were not elevated significantly in these diseases, although several patients had higher levels of serum IL-10 than controls. These findings suggest that simultaneous activation of both Th1 and Th2 cells may occur during the acute stage, indicating systemic involvement of the immune system in patients with MS, GBS and MFS. Levels of serum IFN-gamma were two- to three-fold higher than those of serum IL-4 in all three demyelinating diseases. We may then conclude that Th1 response may be dominant in GBS and MFS during the acute stage.

Role of the brain in interleukin-6 modulation

High levels of interleukin 6 (IL-6) have been found in the brain tissue or cerebrospinal fluid (CSF) in several CNS disorders including Alzheimer's disease, AIDS dementia complex, multiple sclerois, stroke, Parkinson's disease, traumatic brain injuries, brain tumors and CNS infections. In these diseases, IL-6 is also found in blood showing that CNS conditions can elicit a peripheral immune response. A direct secretion of IL-6 from brain to blood has been shown to be a major mechanism by which the brain activates peripheral metabolic, endocrine and immune responses. However, this communication is not straightforward and other regulatory mechanisms are likely to be there. Several lines of evidence obtained in the laboratory have shown that the brain significantly modulates IL-6 production in the periphery. Evidence will be given that: (i) central inflammatory stimuli efficiently induce peripheral IL-6; (ii) central opioids are effective modulators of peripheral IL-6, and (iii) the sympathetic nervous system represents an inhibitory pathway to peripheral IL-6.

Cytokine production and the pathogenesis of experimental autoimmune neuritis and Guillain-Barré syndrome

Acute inflammatory demyelinating polyradiculoneuropathy (Guillain-Barré syndrome, GBS) and its animal model experimental autoimmune neuritis (EAN) are prototypes of T cell-mediated autoimmune diseases affecting the peripheral nervous system (PNS). Perivascular accumulation of macrophages and T lymphocytes in the PNS, and high levels systemically of PNS myelin antigen-reactive T cells are characteristic features of both diseases, thereby suggesting a pathogenic role for immunoregulatory cytokines. Here we summarise recent studies that have clearly documented that Th1/Th2/Th3 cytokines are differently upregulated during various clinical phases of EAN and GBS. The observations indicate that the role of cytokines in immune regulation and autoimmune disease is more complex than a simple Th1-Th2 dichotomy would suggest. New treatments may be searched for that counteract this complex cytokine imbalance. Treatments with antibodies that selectively target certain pro-inflammatory cytokines, as well as with immunomodulatory preparations that promote cytokines that beneficially influence the disease course should be in focus of future therapeutic trials.

Multiple sclerosis: IL-2 and sIL-2R levels in cerebrospinal fluid and serum. Review of literature and critical analysis of ELISA pitfalls

The presence of interleukin-2 (IL-2) and soluble IL-2 receptors (sIL-2R) in the serum and cerebrospinal fluid (CSF) of patients suffering from multiple sclerosis (MS) has been extensively investigated. These studies, however, have produced conflicting results. The only significant finding concerns the frequent detection of increased sIL-2R levels in the serum in patients with relapsing-remitting MS (RRMS), especially after a short interval of time from the last relapse. Whether this finding can be used for clinical purposes requires further investigation. A standardization of the ELISA methods used to detect cytokines in biological fluids is urgently needed. Increased serum and/or CSF levels of IL-2 and sIL-2R strongly confirm a CD4+ Th1 activation.

Free radicals in inflammatory neurological disease: increased lipid peroxidation and haptoglobin levels in Guillain Barré syndrome

Oxidative damage in three inflammatory neurological disorders; Guillain Barré syndrome (GBS), multiple sclerosis and aseptic meningitis, were assessed by measuring the peroxidation of lipids in body fluids. The results were compared to a control group consisting of patients with either migraine, chronic/tension headaches, benign intracranial hypertension or psychological disorders. Antioxidant status was assessed by the measurement of the extracellular proteins, haptoglobin, albumin, caeruloplasmin and transferrin. The results of the study suggested that firstly, haptoglobin levels might be a useful, easily obtainable marker to aid the diagnosis of GBS. Secondly, free radical damage may be implicated in the pathology of GBS and therefore appropriate free radical scavenging might have beneficial effects.

Substance P induces secretion of immunomodulatory cytokines by human astrocytoma cells

In human astrocytoma cell lines, substance P (SP) stimulated interleukin (IL)-8, IL-6, granulocyte macrophage colony-stimulating factor and leukemia inhibitory factor protein secretion. These SP effects were blocked by a specific NK1 tachykinin receptor antagonist. Further, SP stimulation increased the half-life of IL-6 and IL-8 messenger RNAs, suggesting that the synthesis of these cytokines is also regulated post-transcriptionally. SP-induced cytokine release was inhibited by staurosporine and phorbol 12-myristate 13-acetate desensitization suggesting protein kinase C involvement. The demonstration that SP affects cytokine production in glioma cells might be of relevance for the biology of such tumors.

Identification of interleukin-6 producing fibroblastoid cells in cerebrospinal fluid from patients with leukemic meningitis

Cytokine producing native cells in cerebrospinal fluid (CSF) have not been identified. So, we investigated the cytokine producing ability of floating cells in CSF from patients with leukemic meningitis. Morphologic study revealed that established cell lines were polygonal or elongated in shape and had an abundant and irregular branched cytoplasm. Immunocytochemical analysis demonstrated positive reactivity with monoclonal anti-fibroblast antibody only. Interleukin-6 (IL-6) was constitutively produced in vitro by these cell lines; both interleukin-1 and lipopolysaccharides significantly increased its synthesis. These findings imply that these fibroblastoid cells are floating in CSF of patients with leukemic meningitis and produce IL-6 in response to various inflammatory stimulations in vivo.

Correlation between interferon production and clinical disease activity in patients with multiple sclerosis

We determined the interferon (IFN) serum levels and in vitro activated IFN production in eight patients with relapsing/ remitting multiple sclerosis (MS), using a whole-blood test system and the mitogen concanavalin A and the viral antigen Newcastle disease virus for induction of the IFN production. During the overall study period of 12 months we observed, in relation to clinical disease progression, a biphasic increase in the individual IFN alpha and IFN gamma production. While mitogen-induced IFN gamma synthesis showed a significant augmentation prior to the onset of a new relapse (P < 0.05), virus-induced IFN alpha production showed a temporal delayed increase which was related to clinical remission (P < 0.01). The observed fluctuations in the individual production of both IFN subtypes were not reflected in the sera of the patients. Although the reason for the temporal different imbalance in the production of both IFN subtypes remains unknown, the observed association between increased IFN alpha production and clinical remission emphasizes a possible role for type 1 IFNs in the resolution of the MS relapse.

Immunologically induced electrophysiological dysfunction: implications for inflammatory diseases of the CNS and PNS

During inflammation of the central or peripheral nervous system, a high number of immunologically active molecules, including bacterial or viral products as well as host-derived cytokines, are released. Patients suffering from inflammatory CNS or PNS diseases often develop transient symptoms with a rapid recovery, which obviously cannot be accounted for by immunologically induced tissue damage. These observations led to the hypothesis that immunologically active molecules can affect directly the electrophysiological functions of neurons and glial cells. Evidence for this hypothesis came from in vitro studies showing that cytokines, such as interleukins or tumor necrosis factors, arachidonic acid and its metabolites, interfere with electrophysiological properties of neurons or glial cells. These molecules affect ion currents, intracellular Ca2+ homeostasis, membrane potentials, and suppress or enhance the induction and maintenance of long-term potentiation. Similarly, virus proteins from human immunodeficiency virus type I were found to alter intracellular Ca2+ concentrations of neurons and astrocytes by modulating either transmitter receptors and channels or membrane transporters. Cerebrospinal fluid from MS patients contains factors which increase Na+ current inactivation and thereby reduce neuronal excitability. Immunoglobulins in sera of patients suffering from multifocal motor neuropathy and from acquired neuromyotonia interfere with nerve fibers, inducing alterations of conduction. Increased knowledge of these mechanisms will help to explain the pathogenesis of neurological symptoms and may provide a rationale for new therapeutic strategies.

Cytokine pattern in the cerebrospinal fluid from patients with GBS and CIDP

Macrophage-colony stimulating factor (M-CSF) and, less frequently, IL-1 beta and IL-6 were detected in the cerebrospinal fluid (SF) from Guillain-Barré syndrome (GBS) patients. IL-1 alpha, IL-2, IL-10, TNF alpha, and IFN gamma were not found. Detectable cytokine levels were not observed in chronic inflammatory demyelinating polyneuropathy (CIDP) SF nor in any of the sera studied. These findings suggest a prominent intrathecal activation of cells of the monocyte/macrophage lineage (Mø) in GBS, and further support the hypothesis of a crucial role for Mø in GBS immunopathology.

Expression of tumor necrosis factor-alpha and transforming growth factor-beta 1 in cerebrospinal fluid cells in meningitis

Meningitis is an acute inflammatory disease of the pia and arachnoid and the fluid in the subarachnoid space, in which a participation of cytokines can be expected. While tumor necrosis factor-alpha (TNF alpha) promotes inflammatory reactions, transforming growth factor-beta 1 (TGF beta 1) has antagonistic effects and suppresses the inflammation in the subarachnoid space. We investigated the protein concentration and mRNA expression of TNF alpha and TGF beta 1 in cerebrospinal fluid (CSF) by ELISA and intracellularly by non-radioactive in situ hybridization in 23 patients with bacterial or viral meningitis. A higher amount of both cytokines on protein and mRNA level, especially of TNF alpha, could be detected in bacterial infection. While an imbalance of both cytokines with a preponderance of TNF alpha- compared to TGF beta 1-mRNA was visible in CSF cells of patients with bacterial meningitis, a balance of TNF alpha- and TGF beta 1-mRNA or a higher expression of TGF beta 1-mRNA could be detected in viral meningitis. In the acute phase of the disease neutrophil granulocytes expressed more TNF alpha- and TGF beta 1-mRNA than lymphocytes and monocytes/macrophages, while these cell types were dominating the cytokine synthesis during the healing phase. These data indicate that immunomodulatory mechanisms take place in the CSF compartment itself, regulated by CSF cells in different but specific ways. In addition, TGF beta 1 seems to be involved in the down-regulation of the inflammatory activity and to be one factor in the cytokine network, which could contribute to a lower rate of complications and positive outcomes. Moreover this study favors the possibility to monitor the immunomodulatory mechanisms by non-radioactive in situ hybridization.

Tumor necrosis factor alpha and interleukin-6 mRNA expression in neonatal Lewis rat Schwann cells and a neonatal rat Schwann cell line following interferon gamma stimulation

There is increasing evidence that Schwann cells play an important role in the pathogenesis of autoimmune inflammatory peripheral nerve disease. Schwann cells have been reported to express major histocompatibility complex class I and II (MHC I and II) and intercellular adhesion molecule-1 (ICAM-1), and to produce interleukin-1 (IL-1), prostaglandin E2 and thromboxane A2. In this study we investigated freshly dissociated neonatal Lewis rat Schwann cells and a SV40 transfected neonatal rat Schwann cell line (Schwann cell line) for production of mRNA for the immunomodulatory cytokines IL-2, IL-4, IL-6, IL-10, interferon-gamma (IFN gamma), and tumor necrosis factor-alpha (TNF alpha) employing RT-PCR. Primary Schwann cells and Schwann cell line were examined following IFN gamma stimulation and were found to express TNF alpha and IL-6 mRNA. These results further support a role for Schwann cell participation in inflammatory responses within the peripheral nervous system (PNS).

Distribution of transforming growth factor-beta isoforms in human immunodeficiency virus-1 encephalitis

The transforming growth factor-beta family of polypeptides includes three related isoforms with pervasive effects on immune system function. In this study, the authors evaluated human brains with human immunodeficiency virus (HIV)-1 encephalitis for transforming growth factor beta (TGFbeta)1, TGFbeta2, and TGFbeta3 immunoreactivity using isoform-specific polyclonal antibodies and avidin-biotin immunohistochemistry. Normal brains and those with progressive multifocal leukoencephalopathy, toxoplasma encephalitis, and cryptococcal meningitis were used as controls. In normal controls, TGFbeta1, TGFbeta2, and TGFbeta3 immunoreactivity were confined to arachnoid cells and blood vessels. In 9 of 10 cases of HIV-1 encephalitis, all three isoforms were also detected in arachnoid cells. In addition, variable, predominantly TGFbeta2 and TGFbeta3 immunoreactivity were also detected in reactive astrocytes and mononuclear cells of white matter lesions. Extensive TGFbeta3 immunoreactivity was also detected in multinucleated giant cells in one case. In a case of cryptococcal meningitis, all three isoforms were detected in arachnoid cells and macrophages. Lesions of progressive multifocal leukoencephalopathy and toxoplasma encephalitis also exhibited TGFbeta1, TGFbeta2, and TGFbeta3 immunostaining in reactive astrocytes. These findings suggest that TGFbeta isoforms are present in HIV-1 encephalitis and may participate in the pathogenesis of this and other inflammatory central nervous system (CNS) lesions associated with acquired immunodeficiency syndrome (AIDS).

Cerebrospinal fluid levels of soluble tumour necrosis factor receptor in acute encephalitis

Soluble tumour necrosis factor receptor (sTNF-R) inhibits the action of TNF-alpha. The level of sTNF-R reflects the true biological activity of TNF-alpha. We investigated whether sTNF-R in cerebrospinal fluid (CSF) and serum increases during the acute stage in patients with acute encephalitis by measuring p60 sTNF-R using a sandwich enzyme immunoassay. The levels of sTNF-R were significantly higher in the CSF and serum of children with acute encephalitis than in those of control subjects. The patients with acute encephalitis who died or had severe neurological sequelae had higher CSF sTNF-R levels than those who survived. There were no significant differences in the serum sTNF-R, serum C-reactive protein and CSF protein levels, and CSF cell counts between the two groups. The sTNF-R levels of 4.0 ng/ml or higher identified patients with acute encephalitis who had neurological sequelae with a sensitivity of 100% (8/8), a specificity of 100% (8/8%), and a predictive value of 100% (8/8). The 95% confidence interval for these three values is 63-100%. Our findings suggest that the CSF level of sTNF-R during the acute stage of encephalitis is important for predicting neurological sequelae.

Tumour necrosis factor alpha is elevated in serum and cerebrospinal fluid in multiple sclerosis and inflammatory neuropathies

Tumour necrosis factor alpha (TNFalpha) is a peptide that is derived from T lymphocytes and macrophages and is used as a marker of activated cellular immune responses. TNFalpha was measured in paired sera and cerebrospinal fluid (CSF) from 30 patients with multiple sclerosis (MS) with worsening disability, 54 patients with other neurological diseases, and 20 normal subjects. A sensitive enzyme-linked immunosorbent assay was used to determine the TNFalpha levels. We found significantly elevated serum and CSF levels in 12 (40%) and 6 (20%) MS patients, respectively, compared with healthy controls (P < 0.007 and P < 0.05). Among the 18 patients with neuropathy, we also found high serum and CSF TNFalpha values in 3 (17%) and 5 (28%) patients, respectively (P < 0.04 and P < 0.002). Our study shows that TNFalpha is probably involved in the pathogenetic mechanisms of MS and other inflammatory neurological diseases.

Significance of elevated levels of soluble factors in the cerebrospinal fluid in patients with adult T-cell leukemia

Although it has been recognized previously that several markers are present in the cerebrospinal fluid (CSF), their clinical usefulness of these markers in the diagnosis of malignant lymphoma infiltrating to the CNS has not yet been established. In order to determine their diagnostic usefulness as markers of meningeal infiltration by lymphoma cells in patients with adult T-cell leukemia (ATL), we measured some soluble factors in the CSF of patients with ATL and non-ATL patients. Soluble CD4 (sCD4) was highly elevated in all patients with ATL and meningeal infiltration. The CSF level of the soluble interleukin-2 receptor (sIL-2R; sCD25) was markedly elevated in 13 (72.2%) of 18 patients with ATL and meningeal infiltration. Levels of sCD4 and sCD25 in the CSF of patients with ATL and meningeal infiltration were significantly higher than in non-ATL patients (p < .01 and p < .001, respectively). These findings indicate that levels of sCD4 and sCD25 in the CSF are probably associated with meningeal infiltration by leukemia cells expressing CD4 and CD25 on surface membranes. CSF levels of sCD4 in 14 (60.9%) of 23 ATL patients and sCD25 in 13 (72.2%) of 18 ATL patients without meningeal infiltration were moderately elevated. These findings suggest that a small number of leukemic cells which were not detected by conventional CSF examination may have infiltrated the meninges in these patients. Sequential measurements of sCD4 and sCD25 in CSF obtained from patients with meningeal infiltration by leukemic cells showed that sCD4 and sCD25 levels reflected the activity of leukemic meningitis and correlated with the number of cells in CSF. However, the levels of sCD4 in CSF did not fall below the limit of detection even when the number of cells in CSF became normal. It is thought that the level of sCD4 in CSF is a more sensitive marker for detecting the infiltration of leukemic cells in CSF than the number of cells present in the CSF considering the clinical course of two patients with acute type ATL. Therefore, ATL patients with meningeal infiltration should receive treatments until sCD4 levels become normal and not just until the number of cells become normal. Our results also suggest that measurement of CSF levels of sCD4 and sCD25 is useful for the differential diagnosis of aseptic meningitis and meningeal infiltration by leukemic cells in patients with smoldering ATL. We conclude that measurement of soluble factors in CSF plays an important role in diagnosis, prophylaxis and treatment of meningitis in patients with ATL.

Inflammatory neuropathies--pathogenesis and the role of intravenous immune globulin

The inflammatory neuropathies may be subdivided into an acute form, Guillain-Barré syndrome, and a chronic form referred to as chronic inflammatory demyelinating polyneuropathy. More recently a chronic, asymmetrical pure motor neuropathy with multifocal conduction blocks has been described. All three neuropathies are considered to be immune-mediated. Their response to therapy is discussed, with special emphasis on high-dose intravenous immune globulin. For Guillain-Barré syndrome the efficacy of intravenous immune globulin has been proven in a randomized clinical trial. In chronic inflammatory demyelinating polyneuropathy a response rate of over 60% in newly diagnosed patients is suggested. Clinical prognostic criteria, however, seem to be very important to predict the effect of intravenous immune globulin. In multifocal motor neuropathy intravenous immune globulin is at present the only alternative to cyclophosphamide.