Immunzytologie bei Patienten mit Klinisch Isoliertem Syndrom verdächtig auf Multiple Sklerose

EINLEITUNG: Das Klinisch-Isolierte-Syndrom (CIS) bezeichnet das Auftreten eines ersten fokal-neurologischen Defzits für mindestens 24 Stunden und ist verdächtig für die Entwicklung einer Multiplen Sklerose (Kappos u. a. 2006). Neben autoreaktiven, proinflammatorischen T-Zellen (Bhat, Steinman 2009),...

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Bibliographic Details
Main Author: Elzer, Johannes Till
Contributors: Tackenberg, Björn (Dr.) (Thesis advisor)
Format: Doctoral Thesis
Language:German
Published: Philipps-Universität Marburg 2012
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INTRODUCTION: The term Clinically Isolated Syndrome' (CIS) describes a first focal-neurological, demyelinating event lasting for at least 24 hours and is equivocal for the development of definitive Multiple Sclerosis (MS) (Kappos et al. 2006). Besides peripherically activated autoreactive T-cells who reencounter their specific antigen within the borders of human CNS and induce proinflammatory tissue reactions, other immune cells of the innate and adaptive immunesystem like B-cells, plasmacells, monocytes and macrophages play a major role in the pathogenesis of MS (Kuenz et al. 2008; Schneider-Hohendorf et al. 2010; Walter et al. 2006). In particular, CD25high regulatory T-cells seem to be involved due to a hampered executive cell function (Venken et al. 2010). Maintenance of immunehomeostasis across the humoural compartments peripheral blood (PBL) and cerebrospinal fluid (CSF) is crucial for initiation and control of inflammatory CNS reactions and the quantification of leukocytes in peripheral blood and cerebrospinal fluid in patients with CIS and MS has been used to describe a given dysbalance (Engelhardt, Ransoho 2005; Feger et al. 2007a). In the past, MRI findings have been successfully introduced as a predictor of frequency and gravidity of subsequent relapses and for the future degree of disability (Brex et al. 2002; Kappos et al. 2006). The aim of the present study is to investigate if there is an existing imbalance between leukocytes in PBL and CSF in patients with CIS compared to controls and if the degree of a given imbalance correlates with CNS inflammation, measured as T2- yperintense total lesion volume in MRI. MATERIAL: Venous peripheral blood and cerebrospinal fluid samples of 64 untreated patients with CIS, 18 patients with MS and 43 patients with other non-inflammatory neurological deseases (ONID)have been stained with antibodies against CD3, CD4, CD8, CD14, CD16, CD19, CD20, CD25, CD27, CD28, CD45RA, CD49d, CD62L and CD138 and analyzed flowcytometrically according to published methods (Tackenberg et al. 2007). MRI T2-hyperintense total lesion volume of each single patient has been calculated in a standardized way (MS-programme', sag. T2 FS, ax. T1 SE, ax. FLAIR, ax. PD und T2, ax. T1 SE + CA) and correlated with the PBL/CSF ratio of specific immunecell subsets. EDSS-score at desease onset has been taken and a ROC analysis has been performed in cases of diverging ratios. In a subgroup of CIS patients (n=18), mean fluorescence intensity (MFI) for VLA-4 (CD49d) has been measured for different expression levels of CD25 in CD4+ lymphocytes. RESULTS: Significant differences in CIS PBL/CSF ratios have been found for regulatory T- ells, CD19+ B-cells and CD16+ monocytes compared to ONID. ROC analysis for the samesubsets revealed significance and a specific cut-off has been determined to discriminate between ill' and healthy'. Positive correlation with cranial total volume lesion load has been found for regulatory T-cells (r=0,68) and plasmacells (r=0,55), a negative correlation for CD4+ thymic emigrants (r=-0,53). Best correlation coefficients could be achieved for stratification for early CIS (less than 7 lesions). VLA-4 MFI on CD4+CD25lo-hi lymphocytes in PBL and CSF was significantly higher in patients with OIND than in CIS. DISCUSSION: In contrast to controls, patients with CIS seem to have a significantly reduced relative proportion of regulatory T-cells in cerebrospinal fluid compared with peripheral blood and a significantly higher relative proportion of CD19 B-cells, memory B-cells and CD16+ monocytes. Apart from a known dysfunction in regard to executive features (Venken et al. 2006), there seems to be a quantitative disorder in regulatory T-cells, probably due to a reduced cell surface expression of the cell-adhesion molecule VLA-4 on CD4+ lymphocytes of patients with CIS. In these patients, especially in an early CIS stage, regulatory T-cells might have an antiinflammatory effect and the PBL/CSF ratio provides a surrogatemarker for diagnosis and disease activity. The correlation of plasmacells with the cranial total lesion load is most probably considered an incidental result. The negative correlation of naive thymic emigrants is indicating a possible role in early pathogenesis. In conclusion, there seems to be a given dysequilibrium in immune homeostasis of certain leukocytes involved in pathogenesis and pathophysiology of early MS that is probably the result of a disturbed cell surface adhesion molecule expression. The numerical quantity of the relative dysbalances in peripheral blood or cerebrospinal fluid represents cerebral inflammation measured in cranial MRI and is probably suited as lab marker for diagnosis of CIS.