Dynamic of CSF and serum biomarkers in HIV-1 subtype C encephalitis with CNS genetic compartmentalization-case study.

Despite the effective suppression of viremia with antiretroviral therapy, HIV can still replicate in the central nervous system (CNS). This was a longitudinal study of the cerebrospinal fluid (CSF) and serum dynamics of several biomarkers related to inflammation, the blood-brain barrier, neuronal injury, and IgG intrathecal synthesis in serial samples of CSF and serum from a patient infected with HIV-1 subtype C with CNS compartmentalization.The phylogenetic analyses of plasma and CSF samples in an acute phase using next-generation sequencing and F-statistics analysis of C2-V3 haplotypes revealed distinct compartmentalized CSF viruses in paired CSF and peripheral blood mononuclear cell samples. The CSF biomarker analysis in this patient showed that symptomatic CSF escape is accompanied by CNS inflammation, high levels of cell and humoral immune biomarkers, CNS barrier dysfunction, and an increase in neuronal injury biomarkers with demyelization. Independent and isolated HIV replication can occur in the CNS, even in HIV-1 subtype C, leading to compartmentalization and development of quasispecies distinct from the peripheral plasma. These immunological aspects of the HIV CNS escape have not been described previously. To our knowledge, this is the first report of CNS HIV escape and compartmentalization in HIV-1 subtype C.

RANTES levels in peripheral blood, CSF and contused brain tissue as a marker for outcome in traumatic brain injury (TBI) patients.

BACKGROUND: Traumatic brain injury (TBI) causes activation of several neurochemical and physiological cascades, leading to neurological impairment. We aimed to investigate the level of novel chemokine RANTES in plasma, cerebrospinal fluid (CSF) and contused brain tissue in traumatic brain injury patients and to correlate the expression of this chemokine with the severity of head injury and neurological outcome. METHODS: This longitudinal case control study was performed on 70 TBI patients over a period of 30 months. Glasgow coma scale (GCS) and Glasgow outcome score were used to assess the severity of head injury and clinical outcome. Level of RANTES was quantified in plasma (n = 60), CSF (N = 10) and contused brain tissue (n = 5). Alterations in the plasma levels on 1st and 5th day following TBI were assessed. Patients were categorized as severe (GCS < 8) (SHI), moderate and mild Head injury (GCS > 8-14). 15 healthy volunteers were taken as the control group. RESULTS: The median plasma RANTES levels were 971.3 (88.40-1931.1); 999.2 (31.2-2054.9); 471.8 (370.9-631.9) for SHI, MHI and healthy control respectively and showed statistically significant variation (p = 0.005). There was no statistical difference in the mean 1st and 5th day RANTES levels for the SHI group. However, admission RANTES levels were significantly higher in patients who died than those who survived (p = 0.04). Also, RANTES levels were significantly higher in plasma as compared to contused brain tissue and CSF (p = 0.0001). CONCLUSION: This is the first study of its kind which shows that there is significant correlation of admission RANTES levels and early mortality. Another interesting finding was the significant upregulated in the expression of RANTES in plasma, compared to CSF and contused brain tissue following severe TBI.

RANTES correlates with inflammatory activity and synaptic excitability in multiple sclerosis.

BACKGROUND: Alterations of synaptic transmission induced by inflammatory activity have been linked to the pathogenic mechanisms of multiple sclerosis (MS). Regulated upon activation, normal T-cell expressed, and secreted (RANTES) is a pro-inflammatory chemokine involved in MS pathophysiology, potentially able to regulate glutamate release and plasticity in MS brains, with relevant consequences on the clinical manifestations of the disease. OBJECTIVE: To assess the role of RANTES in the regulation of cortical excitability. METHODS: We explored the association of RANTES levels in the cerebrospinal fluid (CSF) of newly diagnosed MS patients with magnetic resonance imaging (MRI) and laboratory measures of inflammatory activity, as well its role in the control of cortical excitability and plasticity explored by means of transcranial magnetic stimulation (TMS), and in hippocampal mouse slices in vitro. RESULTS: CSF levels of RANTES were remarkably high only in active MS patients and were correlated with the concentrations of interleukin-1ß. RANTES levels were associated with TMS measures of cortical synaptic excitability, but not with long-term potentiation (LTP)-like plasticity. Similar findings were obtained in mouse hippocampal slices in vitro, where we observed that RANTES enhanced basal excitatory synaptic transmission with no effect on LTP. CONCLUSION: RANTES correlates with inflammation and synaptic excitability in MS brains.

Cytokine responses and correlations thereof with clinical profiles in children with enterovirus 71 infections.

BACKGROUND: Severe complications associated with EV71 infections caused many infants death. However, the pathogenesis of EV71 infection in the severe cases remained poorly understood. METHODS: In this study we collected plasma and cerebrospinal fluid (CSF) specimens drawn in the acute and/or recovery phases from EV71-infected individuals, and plasma specimens from healthy children served as normal controls. We compared the levels of cytokines and chemokines determined by a Luminex-based cytokine bead array. RESULTS: The plasma levels of IL-1ß and IL-6 were significantly higher in severe and critical cases than in mild patients and normal controls. Higher plasma levels of IL-6, IL-10, and IL-8 were evident in critical than severe cases. The CSF levels of IL-6, IL-8, and IP-10 were higher, and that of RANTES lower (compared to plasma), in severe and critical patients. Significantly lower CSF levels of cytokines and chemokines were recorded in the recovery than the acute phase in severe and critical cases treated with intravenous immunoglobulin (IVIG) and glucocorticoids. Only the CSF levels of IL-6, IP-10, and IL-8 were significantly correlated with white blood cell counts, and absolute neutrophil and monocyte counts, in severe cases. Furthermore, the CSF levels of IL-6 were correlated with temperature in both cases. CONCLUSIONS: These data indicate that a major cytokine response and inflammation, in both plasma and the CNS, are features of disease caused by EV71 infection. Systemic inflammation caused by EV71 infection exacerbated the deterioration of the disease, and resulted in the disease progression to the critical illness stage.

Involvement of PGE2 and RANTES in Staphylococcus aureus-induced fever in rats.

This study investigated the involvement of prostaglandins and regulated on activation, normal T cell expressed and secreted (RANTES), in fever induced by live Staphylococcus aureus (no. 25923, American Type Culture Collection) injection in rats. S. aureus was injected intraperitoneally at 10(9), 10(10), and 2 × 10(10) colony-forming units (CFU)/cavity, and body temperature (T(b)) was measured by radiotelemetry. The lowest dose of S. aureus induced a modest transient increase in T(b), whereas the two higher doses promoted similar long-lasting and sustained T(b) increases. Thus, the 10(10) CFU/cavity dose was chosen for the remaining experiments. The T(b) increase induced by S. aureus was accompanied by significant decreases in tail skin temperature and increases in PGE(2) levels in the cerebrospinal fluid (CSF) and hypothalamus but not in the venous plasma. Celecoxib (selective cyclooxygenase-2 inhibitor, 2.5 mg/kg po) inhibited the fever and the increases in PGE(2) concentration in the CSF and hypothalamus induced by S. aureus. Dipyrone (120 mg/kg ip) reduced the fever from 2.5 to 4 h and the PGE(2) increase in the CSF but not in the hypothalamus. S. aureus increased RANTES in the peritoneal exudate but not in the CSF or hypothalamus. Met-RANTES (100 µg/kg iv), a chemokine (C-C motif) receptor (CCR)1/CCR5 antagonist, reduced the first 6 h of fever induced by S. aureus. This study suggests that peripheral (local) RANTES and central PGE(2) production are key events in the febrile response to live S. aureus injection. As dipyrone does not reduce PGE(2) synthesis in the hypothalamus, it is plausible that S. aureus induces fever, in part, via a dipyrone-sensitive PGE(2)-independent pathway.

Acute chemokine response in the blood and cerebrospinal fluid of children with enterovirus 71-associated brainstem encephalitis.

BACKGROUND: Brainstem encephalitis (BE) is a serious neurological complication of enterovirus 71 (EV71) infection. The present study was designed to determine the characteristics of the chemokine response in the blood and cerebrospinal fluid (CSF) of patients with EV71-associated BE. METHODS: Thirty-one patients with BE were studied. They consisted of 12 with uncomplicated BE, 9 with autonomic nervous system (ANS) dysregulation, and 10 with pulmonary edema (PE); 13 healthy control subjects were also studied. Plasma and CSF concentrations of various chemokines were determined by a particle-based flow cytometry immunoassay. RESULTS: Plasma levels of interferon (IFN)-gamma-induced protein (IP)-10, monocyte chemoattractant protein (MCP)-1, monokine induced by IFN-gamma (MIG), and interleukin (IL)-8 were significantly higher in patients with PE than in those with uncomplicated BE. CSF levels of MIG were significantly higher in patients with PE than in those with uncomplicated BE and ANS dysregulation. The ratios of mean CSF to plasma levels for MCP-1 and IL-8 were highest in patients with uncomplicated BE and tended to fall with increasing severity of the disease. CONCLUSIONS: Overexpression of the chemokine cascade in the central nervous system compartment appears to play an important role in the elicitation of the immune response to EV71. The chemokine CSF to plasma ratios suggest that IL-8, IP-10, MCP-1, and possibly MIG-but not RANTES-are synthesized in the brain in response to encephalitis.

Cerebrospinal fluid and serum biomarkers of cerebral malaria mortality in Ghanaian children.

BACKGROUND: Plasmodium falciparum can cause a diffuse encephalopathy known as cerebral malaria (CM), a major contributor to malaria associated mortality. Despite treatment, mortality due to CM can be as high as 30% while 10% of survivors of the disease may experience short- and long-term neurological complications. The pathogenesis of CM and other forms of severe malaria is multi-factorial and appear to involve cytokine and chemokine homeostasis, inflammation and vascular injury/repair. Identification of prognostic markers that can predict CM severity will enable development of better intervention. METHODS: Postmortem serum and cerebrospinal fluid (CSF) samples were obtained within 2-4 hours of death in Ghanaian children dying of CM, severe malarial anemia (SMA), and non-malarial (NM) causes. Serum and CSF levels of 36 different biomarkers (IL-1beta, IL-1ra, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-12 (p70), IL-13, IL-15, IL-17, Eotaxin, FGF basic protein, CRP, G-CSF, GM-CSF, IFN-gamma, TNF-alpha, IP-10, MCP-1 (MCAF), MIP-1alpha, MIP-1beta, RANTES, SDF-1alpha, CXCL11 (I-TAC), Fas-ligand [Fas-L], soluble Fas [sFas], sTNF-R1 (p55), sTNF-R2 (p75), MMP-9, TGF-beta1, PDGF bb and VEGF) were measured and the results compared between the 3 groups. RESULTS: After Bonferroni adjustment for other biomarkers, IP-10 was the only serum biomarker independently associated with CM mortality when compared to SMA and NM deaths. Eight CSF biomarkers (IL-1ra, IL-8, IP-10, PDGFbb, MIP-1beta, Fas-L, sTNF-R1, and sTNF-R2) were significantly elevated in CM mortality group when compared to SMA and NM deaths. Additionally, CSF IP-10/PDGFbb median ratio was statistically significantly higher in the CM group compared to SMA and NM groups. CONCLUSION: The parasite-induced local cerebral dysregulation in the production of IP-10, 1L-8, MIP-1beta, PDGFbb, IL-1ra, Fas-L, sTNF-R1, and sTNF-R2 may be involved in CM neuropathology, and their immunoassay may have potential utility in predicting mortality in CM.

RANTES levels are elevated in serum and cerebrospinal fluid in patients with amyotrophic lateral sclerosis.

Immunological disturbances have been implicated in the pathogenesis of amyotrophic lateral sclerosis (ALS). Chemokines are involved in the recruitment of immune cells. Regulated upon activation, normal T-cell expressed and secreted (RANTES) is a C-C beta-chemokine with strong chemo-attractant activity for T-lymphocytes and monocytes. We examined serum levels of RANTES in 20 patients with amyotrophic lateral sclerosis (ALS), 14 patients with non-inflammatory neurological disorders (NIND) and 13 control subjects (CTRL) and cerebrospinal fluid (CSF) levels of RANTES in ALS and NIND group patients in order to investigate whether RANTES as index of immune activation is present in ALS patients. Patients with ALS had higher RANTES levels compared with the NIND patients and CTRL subjects (p = 0.005 and p = 0.02, respectively). CSF RANTES levels were also higher compared with the NIND patients (p = 0.007). No correlation of serum and CSF RANTES levels with disease duration was found. These results may suggest an activated microglia induced recruitment of peripheral inflammatory cells to sites of inflammation in ALS patients.

Proinflammatory cytokines and chemokines in humans with Japanese encephalitis.

BACKGROUND: Japanese encephalitis virus (JEV), the mosquito-borne flavivirus, annually causes an estimated 35,000-50,000 encephalitis cases and 10,000-15,000 deaths in Asia, and there is no antiviral treatment. The role played by the immune response in determining the outcome of human infection with JEV is poorly understood, although, in animal models of flavivirus encephalitis, unregulated proinflammatory cytokine responses can be detrimental. METHODS: We studied the innate, cellular, and humoral immune responses in 118 patients infected with JEV, of whom 13 (11%) died. RESULTS: Levels of interferon (IFN)- alpha , the proinflammatory cytokine interleukin (IL)-6, and the chemokine IL-8 were all higher in the cerebrospinal fluid (CSF) of the nonsurvivors than of the survivors (P=.04, P=.006, and P=.04, respectively), as were both the IL-6 : IL-4 ratio in CSF (a marker of the balance of pro- and anti-inflammatory cytokines) and the level of the chemokine RANTES (regulated on activation, normally T cell expressed and secreted) in plasma (P=.03). In contrast, levels of immunoglobulin (Ig) M and IgG in CSF and of IgM in plasma were higher in the survivors (P=.035, P=.003, and P=.009, respectively). Levels of IFN- gamma and nitric oxide did not vary with outcome. CONCLUSIONS: During JEV infection, elevated levels of proinflammatory cytokines and chemokines are associated with a poor outcome, but whether they are simply a correlate of severe disease or contribute to pathogenesis remains to be determined.

Cerebrospinal fluid and plasma concentrations of proinflammatory mediators in human immunodeficiency virus-infected children.

BACKGROUND: The pathogenesis of HIV encephalopathy is poorly understood especially in children. Studies suggest that HIV replication and the release of proinflammatory mediators in the central nervous system contribute to the pathogenesis of HIV dementia in adults. METHODS: Cerebrospinal fluid (CSF) and plasma samples from 23 HIV-infected children were longitudinally analyzed at Weeks 0, 8, 16 and 48 for HIV RNA and concentrations of the following proinflammatory mediators: monocyte chemotactic protein-1 (MCP-1), tumor necrosis factor-alpha, regulated upon activation, normal T cell expressed and secreted (RANTES), macrophage-inflammatory protein (MIP)-1-alpha, MIP-1-beta and matrix metalloproteinase-9 (MMP-9). RESULTS: All 23 children had detectable concentrations of MCP-1 in the CSF at all time points evaluated. However, of the remaining of proinflammatory mediators measured in CSF at baseline, only a few children had detectable concentrations: tumor necrosis factor-alpha, n = 1; RANTES, n = 5; MMP-9, n = 9; MIP-1-alpha and MIP-1-beta, n = 0. A reduction from baseline to Week 48 was observed in CSF concentrations of MCP-1 and, among children with detectable values, MMP-9, which paralleled declines in CSF HIV RNA. CONCLUSION: These results suggest that MCP-1 and MMP-9 may be involved in the pathogenesis of central nervous system disease in HIV-infected children.

Expression of chemokine receptors in the different clinical forms of multiple sclerosis.

Chemokines and their receptors are important in the trafficking of peripheral leukocytes into the central nervous system, a major event in the pathogenesis of multiple sderosis (MS). Evidence based on clinical, pathological and magnetic resonance imaging grounds supports some divergence between forms of MS with relapses [relapsing-remitting (RR) and secondary progressive (SP)] and the primary progressive (PP) form. To elucidate whether different pathogenic mechanisms are involved in PPMS, we compared membrane expression of a group of CC and CXC chemokine receptors (CCR1, CCR5, CXCR3, CXCR4) in peripheral blood of 68 MS patients (25 PPMS, 23 SPMS and 20 RRMS) and 26 healthy controls. We found a significant increase in surface expression of CCR5 in CD4+, CD8+, CD19+ and CD14+ cells as well as an increased percentage of CXCR3 and CXCR4 in CD14+ cells in MS patients compared to controls. Increased levels of CXCL10 (IP-10) and CCL5 (RANTES) in cerebrospinal fluid were also observed in a subgroup of MS patients. These results support that chemokines and their receptors are involved in the pathogenesis of MS However, a pattem of chemokine-chemokine receptor expression characteristic of each clinical form of the disease failed to be observed.

gamma/delta T cells in multiple sclerosis: chemokine and chemokine receptor expression.

gamma/delta T cells are enriched in multiple sclerosis (MS) brain lesions and have been postulated to contribute to the pathogenesis of the disease. Increased expression of the chemokine receptors CCR5 and CXCR3 on T cells and raised amounts of the chemokines RANTES and IP-10 have been noted in the CSF and brain tissue of MS patients, but the contribution of gamma delta T cells to these increases is unknown. We therefore compared intracellular RANTES and IP-10 production as well as CCR5, CXCR3, and CXCR1 expression by gamma delta T cells derived from the blood and CSF of patients with MS and healthy controls (HC). We observed higher RANTES production by MS gamma delta than by alpha beta T cell lines. Most of the MS as well as the HC gamma delta and alpha beta T cell lines expressed CXCR3, while expression of CXCR1 was low. Interestingly, MS gamma delta T cell lines, compared to lines from HC, expressed lower levels of CCR5. Furthermore, CSF-derived gamma delta T cells had even lower CCR5 expression than blood-derived ones. The higher RANTES production by MS gamma delta T cell lines, together with a lower expression of CCR5, may reflect an autoregulatory loop, caused by an increased production of its ligands (RANTES, MIP-1 alpha, and MIP-1 beta) or due to other pro-inflammatory cytokines. Alternatively, we show that lower CCR5 expression could also reflect the result of repeated in vivo stimulation of gamma delta T cells by autoantigens.

Multiple sclerosis and optic neuritis: CCR5 and CXCR3 expressing T cells are augmented in blood and cerebrospinal fluid.

A role for chemokines as mediators of Th1 cell recruitment to the central nervous system (CNS) is probable in MS. Therefore we studied expression of Th1-related CCR5 and CXCR3 chemokine receptors in patients with MS and controls. Patients with untreated MS had elevated percentages of CCR5 and CXCR3 expressing T cells vs. healthy controls (HC) in blood, and vs. other non-inflammatory neurological diseases (OND) patients in CSF. Such elevation was not found in MS patients examined during ongoing treatment with IFN-beta. Patients with optic neuritis (ON), a common first manifestation of MS, had elevated percentages of CXCR3 expressing T cells in blood compared with HC, and of CCR5 expressing T cells in CSF compared with OND patients. High chemokine receptor expression may be one prerequisite for Th1 cells to migrate to the CNS. Inhibition of chemokine receptor expression may constitute a potentially important therapeutic effect of IFN-beta.

Recruitment of dendritic cells to the cerebrospinal fluid in bacterial neuroinfections.

Dendritic cells (DC) accumulate in the CNS during inflammation and may contribute to local immune responses. Two DC subsets present in human cerebrospinal fluid (CSF) are probably recruited from myeloid (CD11c(+)CD123(dim)) and plasmacytoid (CD11c(-)CD123(high)) blood DC. In bacterial meningitis and especially in Lyme meningoencephalitis, numbers of myeloid and plasmacytoid DC in CSF were increased, compared to non-inflammatory neurological diseases, and correlated with chemotactic activity of CSF for immature monocyte-derived DC (moDC). Multiple DC chemoattractants, including macrophage inflammatory protein (MIP)-1beta, monocyte chemotactic protein (MCP)-1, MCP-3, RANTES and stromal cell-derived factor (SDF)-1alpha were elevated in CSF in these two neuroinfections. Chemotaxis of immature moDC induced by these CSFs could be partially inhibited by mAbs against CXCR4, the receptor for SDF-1alpha, and CD88, the receptor for C5a. SDF-1alpha present in CSF also chemoattracted mature moDC, which in vivo could correspond to a diminished migration of antigen-bearing DC from the CSF to secondary lymphoid organs. Regulation of DC trafficking to and from the CSF may represent a mechanism of controlling the CNS inflammation.

Differential release of beta-chemokines in serum and CSF of patients with relapsing-remitting multiple sclerosis.

OBJECTIVE: beta-chemokines were recently demonstrated in active MS-lesions. We tested whether MCP-1 and RANTES can also be detected in CSF and serum of patients with MS and whether release is associated with inflammatory disease activity. MATERIALS AND METHODS: CSF and serum from 34 patients with newly diagnosed relapsing-remitting MS (RR-MS), 17 patients with viral meningitis (VM) and 19 patients with non-inflammatory neurological diseases (NIND) were investigated by ELISA. RR-MS patients underwent lumbar puncture and Gd-enhanced MRI examinations within 2 days. RESULTS: MCP-1 was strong intrathecally released in all patients. Compared to NIND CSF-levels were increased in VM (P<0.001) and were decreased in RR-MS (P<0.05). RANTES was only detected in serum in all patients. Levels were higher in VM and RR-MS compared to NIND (P<0.05). A total of 14/34 RR-MS patients exhibited active Gd-enhancing lesions on MRI. They had lower MCP-1 levels in CSF (P<0.001) and serum (P<0.05) and higher serum levels of RANTES (P<0.05) as compared to patients without active lesions. CONCLUSIONS: MCP-1 and RANTES are differentially released during acute attacks of RR-MS, which might reflect different immunregulatory roles of these beta-chemokines in RR-MS.

Cerebrospinal fluid beta chemokine concentrations in neurocognitively impaired individuals infected with human immunodeficiency virus type 1.

Macrophages express the chemokine receptor CCR-5, a coreceptor for human immunodeficiency virus (HIV) entry. This receptor is ligated by beta chemokines, which influence HIV type 1 (HIV-1) replication in CCR-5-bearing cells in vitro and could influence the course of infection in the central nervous system. Cerebrospinal fluid (CSF) samples from 73 HIV-infected men were assayed for macrophage inflammatory protein-1 alpha (MIP-1alpha), MIP-1beta, and regulated upon activation, normal T cell expressed and secreted (RANTES). Distributions of all three were positively skewed. CSF chemokine concentrations were correlated with each other and were higher in demented patients. In a multivariate analysis, demented subjects were more likely to have detectable CSF MIP-1alpha, elevated CSF HIV RNA levels, and lower CD4+ cell counts. However, among those with detectable CSF MIP-1alpha, levels were lower in demented patients. CSF beta chemokine elevation is consistent with the macrophage activation known to occur in dementia and with studies of beta chemokine mRNA expression in the brain. Low, but detectable, levels of CSF MIP-1alpha were strongly associated with dementia, suggesting that higher levels may have neuroprotective effects.

Identification of a T cell chemotactic factor in the cerebrospinal fluid of HIV-1-infected individuals as interferon-gamma inducible protein 10.

Central nervous system (CNS) involvement is a prominent feature of human immunodeficiency virus (HIV-1) infection. Monocytes and CD4+ T cells traverse the blood brain barrier (BBB), and serve as vehicles for the virus and perpetrators for brain pathology by their production of neurotoxins. In the present study cerebrospinal fluid (CSF) samples from HIV-1-infected patients were analyzed for the presence of chemotactic factors. All 36 CSF samples from the patients were positive for the CXC chemokine interferon-gamma inducible protein (IP-10), which was not detected in CSF samples of 14 controls. The IP-10 concentrations were higher in HIV-1-infected patients with HIV-1 associated neurologic disorders than in those without neurological deficits. In contrast to IP-10, other chemotactic factors including the CC chemokines MCP-1, MIP-1alpha, MIP-1beta and RANTES and the cytokines IL-15 and IL-16 were either not detected or increased in only less than 30% of the patients. Unlike the CSF samples of controls, all CSF samples from HIV-1-infected patients induced chemotaxis of T cells activated with IL-2. The significance of IP-10 as a T cell chemotactic cytokine in HIV-1-infected CSF is shown by (1) the correlation of the IP-10 levels with the extent of T cell chemotaxis, (2) the neutralization of T cell chemotaxis by anti-IP-10 antibodies and (3) the correlation of the chemotactic response of CSF samples on activated T cells and the CSF white cell count in the patients. Our data provide evidence that IP-10 contributes to the accumulation of activated T cells in the CSF compartment in HIV-1-infected individuals.

Expression of specific chemokines and chemokine receptors in the central nervous system of multiple sclerosis patients.

Chemokines direct tissue invasion by specific leukocyte populations. Thus, chemokines may play a role in multiple sclerosis (MS), an idiopathic disorder in which the central nervous system (CNS) inflammatory reaction is largely restricted to mononuclear phagocytes and T cells. We asked whether specific chemokines were expressed in the CNS during acute demyelinating events by analyzing cerebrospinal fluid (CSF), whose composition reflects the CNS extracellular space. During MS attacks, we found elevated CSF levels of three chemokines that act toward T cells and mononuclear phagocytes: interferon-gamma-inducible protein of 10 kDa (IP-10); monokine induced by interferon-gamma (Mig); and regulated on activation, normal T-cell expressed and secreted (RANTES). We then investigated whether specific chemokine receptors were expressed by infiltrating cells in demyelinating MS brain lesions and in CSF. CXCR3, an IP-10/Mig receptor, was expressed on lymphocytic cells in virtually every perivascular inflammatory infiltrate in active MS lesions. CCR5, a RANTES receptor, was detected on lymphocytic cells, macrophages, and microglia in actively demyelinating MS brain lesions. Compared with circulating T cells, CSF T cells were significantly enriched for cells expressing CXCR3 or CCR5. Our results imply pathogenic roles for specific chemokine-chemokine receptor interactions in MS and suggest new molecular targets for therapeutic intervention.