Torben Lykke Sørensen

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.

CCR1+/CCR5+ Mononuclear Phagocytes Accumulate in the Central Nervous System of Patients with Multiple Sclerosis

Mononuclear phagocytes (monocytes, macrophages, and microglia) are considered central to multiple sclerosis (MS) pathogenesis. Molecular cues that mediate mononuclear phagocyte accumulation and activation in the central nervous system (CNS) of MS patients may include chemokines RANTES/CCL5 and macrophage inflammatory protein-1alpha/CCL3. We analyzed expression of CCR1 and CCR5, the monocyte receptors for these chemokines, on circulating and cerebrospinal fluid CD14+ cells, and in MS brain lesions. Approximately 70% of cerebrospinal fluid monocytes were CCR1+/CCR5+, regardless of the presence of CNS pathology, compared to less than 20% of circulating monocytes. In active MS lesions CCR1+/CCR5+ monocytes were found in perivascular cell cuffs and at the demyelinating edges of evolving lesions. Mononuclear phagocytes in early demyelinating stages comprised CCR1+/CCR5+ hematogenous monocytes and CCR1-/CCR5- resident microglial cells. In later stages, phagocytic macrophages were uniformly CCR1-/CCR5+. Cultured in vitro, adherent monocytes/macrophages up-regulated CCR5 and down-regulated CCR1 expression, compared to freshly-isolated monocytes. Taken together, these findings suggest that monocytes competent to enter the CNS compartment derive from a minority CCR1+/CCR5+ population in the circulating pool. In the presence of ligand, these cells will be retained in the CNS. During further activation in lesions, infiltrating monocytes down-regulate CCR1 but not CCR5, whereas microglia up-regulate CCR5.

Multiple sclerosis: a study of CXCL10 and CXCR3 co-localization in the inflamed central nervous system

T-cell accumulation in the central nervous system (CNS) is considered crucial to the pathogenesis of multiple sclerosis (MS). We found that the majority of T cells within the cerebrospinal fluid (CSF) compartment expressed the CXC chemokine receptor 3 (CXCR), independent of CNS inflammation. Quantitative immunohistochemistry revealed continuous accumulation of CXCR3+ T cells during MS lesion formation. The expression of one CXCR3 ligand, interferon (IFN)-gamma-inducible protein of 10 kDa (IP-10)/CXC chemokine ligand (CXCL) 10 was elevated in MS CSF, spatially associated with demyelination in CNS tissue sections and correlated tightly with CXCR3 expression. These data suggest a critical role for CXCL10 and CXCR3 in the accumulation of T cells in the CNS of MS patients.

Chemokines CXCL10 and CCL2: differential involvement in intrathecal inflammation in multiple sclerosis

Studies of chemokines in cerebrospinal fluid (CSF) of patients with active multiple sclerosis (MS) have indicated that specific chemokines may have important roles in disease pathogenesis. We previously reported that CSF concentrations of CXCL10 (previously known as IP‐10) were elevated in MS patients in relapse, whilst levels of CCL2 (MCP‐1) were reduced. Here, we report a serial analysis of CSF CXCL10 and CCL2 concentrations in 22 patients with attacks of MS or acute optic neuritis (ON) treated with methylprednisolone, and 26 patients treated with placebo in two randomized controlled trials. Chemokine concentrations were measured by enzyme linked immunosorbent assay (ELISA) in CSF obtained at baseline and after 3 weeks, and were compared with other measures of intrathecal inflammation. At baseline CSF concentrations of CCL2 were significantly lower in the patient group than in controls. The levels of CXCL10 were higher in the patient group than in controls but two outliers in the control group also had high CSF concentrations of CXCL10. The CSF concentrations of CXCL10 did not change over time or after treatment. The CSF concentration of CXCL10 was positively correlated with the CSF leukocyte count, the CSF concentration of neopterin, matrix metalloproteinase (MMP)‐9, and intrathecal IgG and IgM synthesis. The concentration of CCL2 increased between baseline for 3 weeks in both groups, more distinctly so in patients treated with methylprednisolone. CCL2 correlated negatively with MMP‐9 and IgG synthesis levels. CXCL10 may be involved in the maintenance of intrathecal inflammation whereas CCL2 correlates negatively with measures of inflammation, suggesting differential involvement of CXCL10 and CCL2 in CNS inflammation.

Chemokine CCL2 and chemokine receptor CCR2 in early active multiple sclerosis

The chemokine monocyte chemoattractant protein (MCP)‐1/CCL2 and its receptor CCR2 have been strongly implicated in disease pathogenesis in experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis (MS), whereas data on the CCL2–CCR2 axis are scarce in MS. We studied the expression of CCR2 on leukocytes in blood and cerebrospinal fluid (CSF) from patients with monosymptomatic optic neuritis and MS, and the concentration of CCL2 in the CSF from these patients. Results were compared with the results in non‐inflammatory neurological controls and were correlated with other parameters (magnetic resonance imaging and CSF data). Our findings suggest a limited role for CCL2/CCR2 in early active MS.

Cerebrospinal fluid levels of chitinase 3-like 1 and neurofilament light chain predict multiple sclerosis development and disability after optic neuritis

Background: Cerebrospinal fluid (CSF) biomarkers have been suggested to predict multiple sclerosis (MS) after clinically isolated syndromes, but studies investigating long-term prognosis are needed. Objective: To assess the predictive ability of CSF biomarkers with regard to MS development and long-term disability after optic neuritis (ON). Methods: Eighty-six patients with ON as a first demyelinating event were included retrospectively. Magnetic resonance imaging (MRI), CSF leukocytes, immunoglobulin G index and oligoclonal bands were registered. CSF levels of chitinase-3-like-1, osteopontin, neurofilament light-chain, myelin basic protein, CCL2, CXCL10, CXCL13 and matrix metalloproteinase-9 were measured by enzyme-linked immunosorbent assay. Patients were followed up after 13.6 (range 9.6–19.4) years and 81.4% were examined, including Expanded Disability Status Scale and MS functional composite evaluation. 18.6% were interviewed by phone. Cox regression, multiple regression and Spearman correlation analyses were used. Results: Forty-six (53.5%) developed clinically definite MS (CDMS) during follow-up. In a multivariate model MRI (p=0.0001), chitinase 3-like 1 (p=0.0033) and age (p=0.0194) combined predicted CDMS best. Neurofilament light-chain predicted long-term disability by the multiple sclerosis severity scale (p=0.0111) and nine-hole-peg-test (p=0.0202). Chitinase-3-like-1 predicted long-term cognitive impairment by the paced auditory serial addition test (p=0.0150). Conclusion: Neurofilament light-chain and chitinase-3-like-1 were significant predictors of long-term physical and cognitive disability. Furthermore, chitinase-3-like-1 predicted CDMS development. Thus, these molecules hold promise as clinically valuable biomarkers after ON as a first demyelinating event.

Altered Expression of CD46 and CD59 on Leukocytes in Neovascular Age-Related Macular Degeneration

PURPOSE To investigate the expression of the complement regulatory proteins CD46, CD55, and CD59 on peripheral leukocytes in neovascular age-related macular degeneration (AMD). DESIGN Prospective, case-control study. METHODS Thirty-five unrelated patients with neovascular AMD and 30 control individuals were included in this case-control study. All participants were subjected to a structured interview and detailed imaging (autofluorescence, digital funduscopy, spectral-domain optical coherence tomography, and fluorescein and indocyanine green angiography in patients suspected of having neovascular AMD) was performed. Fresh ethylenediamine-tetraacetic acid blood was obtained and stained with monoclonal antibodies. Using flow cytometry, the percentage of CD14(+) monocytes, CD45(+) lymphocytes, and CD45(+) granulocytes positive for CD46, CD55, and CD59 was determined in patients with neovascular AMD and was compared with that of controls. RESULTS We found that the expression of CD46 and CD59 was significantly lower on CD14(+) monocytes in patients with neovascular AMD compared with controls (P = .0070). A significantly lower expression of CD46 on lymphocytes was observed in patients with fibrosis compared with patients without fibrosis (P = .010). CONCLUSIONS Our study suggests that neovascular AMD is associated with an inadequate regulation of the complement system, supporting current evidence on the role of complement dysregulation in the pathogenesis of AMD.

Chemokine receptor expression on B cells and effect of interferon-β in multiple sclerosis

We investigated the B-cell expression of chemokine receptors CXCR3, CXCR5 and CCR5 in the blood and cerebrospinal fluid (CSF) from patients in relapse of multiple sclerosis (MS) and in neurological controls. Chemokine receptor expression was also studied in interferon-beta-treated patients with relapsing-remitting or secondary progressive MS. We observed significantly higher expression of CXCR3 on B cells in the CSF in active MS than in controls. Patients with active MS also had higher B-cell expression of CCR5 in blood. No major differences between RRMS and SPMS patients were detected, and chemokine receptor expression was not affected by interferon-beta treatment.

Age-related Macular Degeneration Is Associated with Increased Proportion of CD56+ T Cells in Peripheral Blood

PURPOSE To examine the association between age-related changes in the T-cell compartment and prevalence of age-related macular degeneration (AMD). DESIGN Case-control study. PARTICIPANTS A total of 117 AMD cases and 106 controls were included prospectively. METHODS Fresh-drawn peripheral blood samples were processed for flow cytometric analysis of T-cell populations. Plasma samples were analyzed for anti-cytomegalovirus (CMV) immunoglobulin (Ig)G and complement factor H (CFH) Y402H genotype. The diagnosis of AMD was made according to the Clinical Age-Related Maculopathy Staging System. MAIN OUTCOME MEASURES Association between frequency of aged T cells and prevalence of AMD. RESULTS The prevalence of AMD was associated with distinct age-related changes in the T-cell compartment. Specifically, the patients with AMD had an increased frequency of CD28(-) T cells that expressed the CD56 surface marker (patients, 34.9% vs. aged controls, 25.8%; P = 0.002). Participants in the highest tertile of CD56(+) CD28(-) T cells had an odds ratio (OR) for the presence of AMD of 3.2 (95% confidence interval [CI], 1.2-8.8) after adjustment for CFH genotype, anti-CMV IgG positivity, age, sex, and smoking history. The adjusted OR of the presence of AMD for persons having at least 1 CFH H402 risk allele increased from 3.5 (95% CI, 1.5-8.1) to 13.3 (95% CI, 3.3-53.6) for persons with at least 1 CFH H402 risk allele and above the median level of CD56(+) CD28(-) T cells. CONCLUSIONS We found increased levels of circulating aged CD56(+) CD28(-) T cells in patients with AMD. Although this supports the notion of AMD as a systemic disease, it also suggests that the adaptive immune system is implicated in its pathogenesis.

Chemokine receptor CCR5 in interferon-treated multiple sclerosis

Objective –  To study the relationship between CC chemokine receptor CCR5 expression and disease activity in multiple sclerosis (MS) patients treated with β‐interferon (IFN‐β).