M. Söderström

Optic neuritis Prognosis for multiple sclerosis from MRI, CSF, and HLA findings

We investigated the paraclinical profile of monosymptomatic optic neuritis(ON) and its prognosis for multiple sclerosis (MS). The correct identification of patients with very early MS carrying a high risk for conversion to clinically definite MS is important when new treatments are emerging that hopefully will prevent or at least delay future MS. We conducted a prospective single observer and population-based study of 147 consecutive patients (118 women, 80%) with acute monosymptomatic ON referred from a catchment area of 1.6 million inhabitants between January 1, 1990 and December 31, 1995. Of 116 patients examined with brain MRI, 64 (55%) had three or more high signal lesions, 11 (9%) had one to two high signal lesions, and 41 (35%) had a normal brain MRI. Among 143 patients examined, oligoclonal IgG (OB) bands in CSF only were demonstrated in 103 patients (72%). Of 146 patients analyzed, 68 (47%) carried the DR15,DQ6,Dw2 haplotype. During the study period, 53 patients (36%) developed clinically definite MS. The presence of three or more MS-like MRI lesions as well as the presence of OB were strongly associated with the development of MS (p < 0.001). Also, Dw2 phenotype was related to the development of MS (p = 0.046). MRI and CSF studies in patients with ON give clinically important information regarding the risk for future MS.

Circulating CD4+CD25+ T regulatory cells are not altered in multiple sclerosis and unaffected by disease-modulating drugs.

Experimental animal models for autoimmunity have demonstrated the existence and crucial role of CD4+CD25+ T regulatory (Tr) cells in suppressing autoreactive T cells and promoting peripheral tolerance. Recent in vitro functional studies showed that Tr cells are enriched in the CD25high cell population among CD4+ T cells, and that they totally inhibit proliferation and cytokine secretion by CD4+ T cells. It is not yet known if circulating Tr cells are involved in multiple sclerosis (MS). This study was done firstly to determine whether alterations of the CD4 + CD25high T cells occur in MS, examining their frequencies. As it was reported that the suppressive activity of CD4+CD25+ Tr cells is mainly through cell surface contact pathway, we secondly analyzed the expression of the functionally important cell surface molecules of CD4+CD25high Tr cells. Two- or three-colour flow cytometry was used to identify and quantify CD4+CD25+ Tr cells and CD4+CD25high Tr cells among blood CD4+ T cells in MS patients without treatment vs. patients treated with either interferon-β (IFN-β) or glatiramer acetate (GA) or IFN-β + GA in combination vs. healthy controls (HC). Expression of functionally important surface molecules CD45RO, CD69, CD95, HLA-DR, and intracellular CTLA-4 and IL-10 production by CD4+CD25high Tr cells were investigated. CD4+CD25+ T cells constituted around 6% of CD4+T cells in all MS patient groups, and 7% in HC. There were also no changes in the proportions of CD4+CD25+ Tr cells and CD4+CD25high Tr cells in a longitudinal follow-up of MS patients before and during IFN-β treatment. Frequencies of circulating CD4+CD25highTr cells among CD4+ T cells were also similar and their surface or intracellular molecular expression did not vary in MS patients, irrespective of treatment, compared to HC. This study suggests that levels of circulating CD4+CD25+ Tr cells and CD4+CD25high Tr cells are not altered in MS, and are unaffected by substances currently used to modulate the disease.

Absence of seven human herpesviruses, including HHV-6, by polymerase chain reaction in CSF and blood from patients with multiple sclerosis and optic neuritis

Several members of the herpesvirus family have been implicated in the pathogenesis of multiple sclerosis (MS). Recently, HHV‐6 viral antigen has been demonstrated in association to MS plaques, as well as DNA from human herpesvirus 6 (HHV‐6) in cerebrospinal fluid from a few MS patients by polymerase chain reaction (PCR). In the present study, CSF from patients with MS, optic neuritis and other neurological diseases, as well as consecutive CSF and serum samples from MS patients included in a clinical trial with acyclovir, were analysed by nested PCR for the presence of DNA from herpes simplex virus 1 and 2, Epstein‐Barr virus, varicella zoster virus, cytomegalovirus, human herpesvirus 6 and 7. No virus DNA was found in any CSF (n= 115) or serum (n= 116) sample. These findings argue against a continuous disseminated herpesvirus infection in MS, but do not rule out a lesion‐associated, low‐grade herpesvirus infection within the MS brain.

Secondary lymphoid organ chemokines are elevated in the cerebrospinal fluid during central nervous system inflammation

Secondary lymphoid organ chemokines have been implicated in chronic inflammation. Their expression in the central nervous system (CNS) has not been studied. Here, levels of secondary lymphoid organ chemokines CCL19 (Exodus-3, MIP-3beta), CCL21 (Exodus-2, 6Ckine, SLC) and CXCL12 (SDF-1alpha) were analysed by ELISA in cerebrospinal fluid (CSF) and plasma from patients with multiple sclerosis (MS); acute optic neuritis (ON) with oligoclonal IgG in the CSF (i.e., first bout of MS); acute ON without oligoclonal IgG (non-MS-type ON); other inflammatory neurological diseases (OIND); and non-inflammatory neurological diseases (NIND). NIND CSF contained CCL19 and CXCL12, while CCL21 was not detected. Intrathecal production of CCL19 and CCL21 was elevated in MS, MS-type ON, and OIND, but not in non-MS-type ON. In MS, CSF levels of CCL19 weakly correlated with CSF cell counts. Intrathecal production of CXCL12 was elevated only in OIND. The role of elevated CCL19 and CCL21 in MS could be retention of mature dendritic cells (DC) in the CNS, recruitment of nai;ve T cells and activated B cells, as well as de novo formation of secondary lymphoid structures in MS plaques.

Tumor necrosis factor α-308 alleles in multiple sclerosis and optic neuritis

Abstract Tumor necrosis factor-α (TNF-α), a proinflammatory cytokine, is believed to play an important role in multiple sclerosis (MS) pathogenesis. A bi-allelic polymorphism in the TNF-α promoter region (TNFα-308), has been reported to influence levels of TNF-α production. In the present study, we investigated the TNFα-308 polymorphism in 93 patients with MS, 17 patients with optic neuritis (ON) and 95 healthy individuals using an allele-specific PCR technique. Allelic genotype was compared with TNF-α mRNA expression levels and HLA class II phenotypes. No significant difference regarding the TNFα-308 polymorphism was observed between MS patients and controls. Specifically, the less common allele, TNF2, which is associated with higher expression levels of TNF-α, was somewhat less frequent among MS patients. In fact, analysis of 19 patients homozygous for the MS associated HLA-DR-DQ haplotype HLA-Dw2 showed that this haplotype does not carry the TNF2 allele. In addition, in 47 patients, the TNF-α alleles did not correlate with expression levels measured as numbers of TNF-α expressing cells. Thus, we found no evidence for an important role of TNFα-308 polymorphism for genetic susceptibility to MS.

Organ‐specific autoantigens induce interferon‐γ and interleukin‐4 mRNA expression in mononuclear cells in multiple sclerosis and myasthenia gravis

T cells recognizing the myelin components myelin basic protein (MBP) and proteolipid protein (PLP) are increased in multiple sclerosis (MS), and there are elevated numbers of T cells recognizing the nicotinic acetylcholine receptor (AChR) in myasthenia gravis (MG). However, the cytokine repertoires in these diseases are largely unknown. We adopted in situ hybridization with radiolabeled complementary DNA oligonucleotide probes to enumerate mononuclear cells that expressed the T-helper type 1 (Th1) cell-related interferon-γ (IFN-γ) and Th2-associated interleukin-4 (IL-4) after short-term culture in the presence of autoantigen. High numbers of IFN-γ and IL-4 mRNA-expressing cells in response to MBP and PLP were detected in patients with untreated MS, and to AChR in MG. The levels of IFN-γ and IL-4 mRNA-positive cells in MS after culture in the presence of AChR, and in MG after culture in the presence of MBP or PLP, did not differ from those detected after culture without antigen. The CSF of MS patients contained four- to eightfold more myelin protein-reactive IFN-γ and IL-4 expressing cells. The findings imply that MS and MG are associated with mixed Th1- and Th2-like cell responses directed to organ-specific target antigens.

IL-15 mRNA expression is up-regulated in blood and cerebrospinal fluid mononuclear cells in multiple sclerosis (MS)

IL‐15, produced by monocytes and epithelial cells, is a novel cytokine with actions similar to IL‐2. IL‐15 induces T cell proliferation, B cell maturation and natural killer (NK) cell cytotoxicity, and is a chemoattractant for T cells. We investigated the expression of IL‐15 mRNA in blood and cerebrospinal fluid (CSF) mononuclear cells (MNC) in MS, an inflammatory disease of the central nervous system where cytokines are involved. MS patients had higher numbers of IL‐15 mRNA‐expressing blood MNC than patients with aseptic meningo‐encephalitis (AM) and healthy controls. In CSF, MS patients had even higher numbers of IL‐15 mRNA‐expressing cells than in blood. This discrepancy between IL‐15 mRNA expression between blood and CSF MNC was not seen in AM patients. Patients examined during the secondary chronic‐progressive phase of MS had higher numbers of IL‐15 mRNA‐expressing blood MNC compared with patients examined during the relapsing‐remitting phase. Levels of IL‐15 mRNA‐positive blood MNC were similar in patients with AM, myasthenia gravis, non‐inflammatory neurological diseases and healthy controls. Taken together these data indicate that IL‐15 mRNA expression is up‐regulated in MS, further suggesting a role for proinflammatory cytokines in the pathogenesis of MS.

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

Abstract. 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-β. 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-β.

Seasonal patterns in optic neuritis and multiple sclerosis: a meta-analysis.

To quantify and characterize seasonal variation in monosymptomatic optic neuritis (MON) onsets, multiple sclerosis (MS) onsets and MS exacerbations (MSE), a meta-analysis was performed, using established methods and pooling weighted information obtained from nine reports on MON, six reports on MS onsets and nine reports on MSE, which fulfilled specific criteria for report quality and data homogeneity. The results suggested that MON, MS onsets and MSE in the Northern hemisphere present a similar pattern with highest frequencies in spring and lowest in winter. These differences were highest for MS onsets, 45% with 95% CI 36-55%, and lowest for MSE, 10% with 95% CI 7-13%, statistically significant and robust, insensitive to an alternative seasonal definition, not unduly influenced by any single primary study, and supported by fail-safe N calculations. Random variation, misclassification and publication bias were less likely to account for the reported generalized seasonal patterns.

T Cells Recognizing Multiple Peptides of Myelin Basic Protein are Found in Blood and Enriched in Cerebrospinal Fluid in Optic Neuritis and Multiple Sclerosis

The cause of multiple sclerosis (MS) is unknown. Recently reported abnormal T‐cell responses to several myelin proteins and myelin basic protein (MBP) peptides in peripheral blood constitute one line of evidence that autoimmune mechanisms could be involved in the pathogenesis of the disease. Monosymptomatic unilateral optic neuritis (ON) is a common first manifestation of MS and important to examine for a possible restriction of the T‐cell repertoire early in the disease. T‐cell activities to MBP and the MBP amino acid sequences 63–88, 110–128 and 148–165 were examined by short‐term cultures of mononuclear cells from cerebrospinal fluid (CSF) and blood in the presence of these antigens, and subsequent detection and counting of antigen‐specific T cells that responded by interferon‐gamma (IFN‐γ) secretion. Most patients with MS and ON had MBP and MBP peptide‐reactive T cells in CSF, amounting to mean values of between about 1 per 2000 and 1 per 7000 CSF cells and without immunodominance for any of the peptides. Numbers were 10‐fold to 100‐fold lower in the patients′ blood. Values were similar in ON and MS, and no evidence was obtained for a more restricted T‐cell repertoire in ON. The MBP peptide‐recognizing T‐cell repertoire was different in CSF than in blood in individual patients with ON and MS, thereby giving further evidence for an autonomy of the autoimmune T‐cell response in the CSF compartment. No relations were observed between numbers of autoreactive T cells and presence of oligoclonal IgG bands in CSF or abnormalities on magnetic resonance imaging of the brain in ON or clinical variables of MS. The high numbers of MBP and MBP peptide‐reactive T cells could play a role in the pathogenesis of ON via secretion of effector molecules, one of them being IFN‐γ, as well as in the transfer of ON to MS.