Andreas Bitsch

Relation between humoral pathological changes in multiple sclerosis and response to therapeutic plasma exchange

Early, active multiple sclerosis lesions show four immunopathological patterns of demyelination. Although these patterns differ between patients, multiple active lesions from a given patient have an identical pattern, which suggests pathogenic heterogeneity. Therapeutic plasma exchange (TPE) has been successfully used to treat fulminant demyelinating attacks unresponsive to steroids. We postulated that patients with pattern II would be more likely to improve after TPE than those with other patterns since pattern II lesions are distinguished by prominent immunoglobulin deposition and complement activation. We retrospectively studied 19 patients treated with TPE for an attack of fulminant CNS inflammatory demyelinating disease. All patients with pattern II (n=10), but none with pattern I (n=3) or pattern III (n=6), achieved moderate to substantial functional neurological improvement after TPE (p<0.0001). Patients with multiple sclerosis with pattern II pathology are more likely to respond favourably to TPE than are patients with patterns I or III.

A longitudinal MRI study of histopathologically defined hypointense multiple sclerosis lesions

Severe tissue destruction is the presumed histopathological correlate of hypointense multiple sclerosis (MS) lesions. In this study we correlated changes of lesion hypointensity over time with initial histopathological features in 14 biopsied MS lesions. The extent of hypointensity increased in initially demyelinated plaques and decreased in remyelinating lesions. The initial axonal loss determined the increase of hypointensity over time. In conclusion, both axonal loss and demyelinating activity determine the evolution of hypointensity over time.

Tumour necrosis factor alpha mRNA expression in early multiple sclerosis lesions: Correlation with demyelinating activity and oligodendrocyte pathology

The precise role of tumour necrosis factor alpha (TNFα) in multiple sclerosis (MS) is still controversial. Most findings from the animal model experimental allergic encephalomyelitis have yet to be confirmed in multiple sclerosis. The aim of this study was to define the significance of TNFα with respect to the hallmark of MS, that is demyelination. Therefore, 78 lesion areas from diagnostic brain biopsies of 32 patients were analysed. Lesion demyelinating activity was classified by the presence of myelin degradation products in macrophages and macrophage activation markers. Non‐radioactive in situ hybridisation was carried out to detect TNFα mRNA expressing cells. DNA fragmentation was visualised by TdT‐mediated X‐dUTP nick end labeling. A significantly higher number of cells expressed TNFα mRNA in active demyelinating lesions than in inactive or remyelinating lesions irrespective of the extent of the inflammatory infiltrate. TNFα mRNA expression correlated with the appearance of DNA fragmentation in T lymphocytes and oligodendrocytes within the lesions. In the periplaque white matter, expression of TNFα mRNA negatively correlated with oligodendrocyte numbers. These data support previous findings from animal models and in vitro experiments. Although not proving, the current study strongly suggests a pathogenic role of TNFα in demyelination in human multiple sclerosis and gives further support for TNFα‐directed therapeutic strategies. GLIA 29:366–375, 2000.

Pentoxifylline, a phosphodiesterase inhibitor, induces immune deviation in patients with multiple sclerosis

The outcome of immune responses can be predicted by the lymphokine production pattern of the participating cells. Cytokines of the T helper type 1 (Th1) cells mediate inflammatory responses and delayed-type hypersensitivity (DTH), whereas Th2-like T cells predominantly produce cytokines, which stimulate antibody production by B cells. Immunoregulatory therapy of autoimmune diseases with unknown antigens may be achieved by inhibiting the production of inflammatory cytokines and induction of protective cytokines of Th2-like T cells. To determine the immunoregulatory capacity of the phosphodiesterase inhibitor pentoxifylline (PTX), which is known to suppress the production of tumor necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma), this drug was used in mitogen and antigen-stimulated lymphocyte cultures as well as in patients with multiple sclerosis. PTX significantly decreased TNF-alpha and interleukin-12 (IL-12), whereas it increased IL-4 and IL-10 production. In addition, PTX inhibited cell proliferation, which was associated with a marked reduction in CD25 (IL-2 receptor alpha-chain) and CD54 (intercellular adhesion molecule-1; ICAM-1) expression. Increasing doses of PTX significantly reduced TNF-alpha and IL-12 mRNA expression of blood mononuclear cells, but increased IL-4 and IL-10 expression in eight patients with relapsing-remitting multiple sclerosis. These results indicate that PTX modulates immune reactions favouring a Th2-like response and may therefore be useful for the treatment of autoimmune diseases with a dominant Th1-like T cell response.

A Longitudinal Prospective Study of Soluble Adhesion Molecules in Acute Stroke

BACKGROUND AND PURPOSE Activation of endothelial cells is a consequence of cerebral ischemia and leads to the expression of adhesion molecules such as intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), and E-selectin, which can be released into the blood. This study aimed to define the kinetics of soluble adhesion molecule serum levels after cerebral ischemia and their correlation with the extent of neurological deficits, clinical outcome, and infarct volume as measured on CT scans. Methods-Plasma levels of soluble (s) ICAM-1, sVCAM-1, and sE-selectin were repeatedly determined by ELISA in 38 patients during a period of 14 days after acute cerebral ischemia. RESULTS Soluble adhesion molecule levels demonstrated considerable variability. Overall, concentrations revealed characteristic and significant changes after completed strokes but not after transient ischemic attacks. In patients with completed stroke (n=26) but not in patients with transient ischemic attacks (n=12), sICAM-1 peaked within 24 hours (P=0.04), sVCAM-1 reached a maximum after 5 days (P=0.02), and sE-selectin levels decreased after 5 days (P=0.002). There was no clear-cut correlation of soluble adhesion molecule levels with infarct volume or clinical disability. The initial increase of sE-selectin levels was higher in more disabled patients (P=0.02). sICAM-1 levels were higher in patients with signs of infection (n=9; P=0.03). CONCLUSIONS As a result of large interindividual variability influenced by ischemia-independent factors, soluble adhesion molecules are not reliable candidates as surrogate markers in acute cerebral ischemia. The characteristic profile of individual soluble adhesion molecules after completed stroke supports prior hypotheses of their involvement in the pathogenesis of acute cerebral ischemia, but this needs to be clarified in detail.

Costs and quality of life in multiple sclerosis

We performed a cross-sectional, “bottom-up” observational study of resource use, costs, and quality of life in patients with multiple sclerosis (MS) in Germany. Six centers participated in the study. Patients were asked to complete a questionnaire, and a total of 737 patients returned it (response rate 66%). The questionnaire provided information on all resource consumption, medical, and nonmedical, work absence, informal care related to their MS, and quality of life (EuroQol). Simultaneously, medical charts were also abstracted for a subsample of 202 patients for comparison between answers in the questionnaires and registered data. Levels of disability were assessed using the Expanded Disability Status Scale. The mean age of the cohort was 41.9±14.1 years (disease onset 33.4), mean EDSS score 4.4 (range 1.0–9.5), and mean utility measured by EQ-5D 0.552±0.331). Mean total cost per patient and year was 65,400 DM, adjusted for use of interferons, which was higher in this sample than the current average use in Germany. When this cost is extrapolated to an estimated patient population of 120,000, total costs to society are estimated at 7.85 billion DM. Direct costs represented 57.5%, informal care accounted for 12.1% and indirect costs amounted to 42.5%. Public payers pay for an estimated 24,800 DM per patient or 38% of total costs. All types of costs (direct, informal care, indirect) increased with increasing disability, while utilities decreased.

Serum tau protein level as a marker of axonal damage in acute ischemic stroke.

Biochemical markers of brain damage, e.g. ischemic stroke, should reflect the volume of irreversibly damaged brain parenchyma and the clinical outcome in a single patient in order to allow estimation of prognosis at an early stage. Tau protein, which derives predominantly from neurons and axons, is elevated in the cerebrospinal fluid of patients with neurodegenerative disease. This makes tau protein a potential marker of neuronal/axonal injury. In order to test this hypothesis, the current study aimed at showing that tau protein is measurable in the blood after acute ischemic stroke and that it correlates with clinical disability and stroke volume. In a longitudinal prospective study we measured tau protein serum levels with an ELISA in 30 patients longitudinally after ischemic stroke. Tau protein was detectable within 5 days after ischemia in the sera of 7/20 patients with MRI-proven infarction and in 2/10 patients with transitory ischemic attack; both of them had a small infarction visible on the MRI scan. Tau protein was measurable within 6 h after symptom onset, peaked after 3–5 days and correlated with infarct volume and disability after 3 months. In conclusion, serum tau protein is a candidate marker of axonal injury. In stroke, its clinical use is limited, because it is detectable only in a proportion of patients.

Failure to detect human cytomegalovirus DNA in peripheral blood leukocytes of healthy blood donors by the polymerase chain reaction

The transmission of cytomegalovirus (CMV) by blood transfusion may have a major effect on certain immunocompromised patients. To protect susceptible blood recipients from infection, it is advisable to use blood components from CMV‐seronegative donors. However, serologic tests are not capable of indicating which blood component actually harbors infectious virus and can transfer it to the recipient. Therefore, a sensitive method is needed for the detection of the virus itself. There have been three reports on the detection of CMV in healthy volunteer blood donors by the polymerase chain reaction (PCR). CMV DNA was found in all seropositive and most seronegative blood donors. However, many other authors have failed to confirm these data. A highly sensitive and specific PCR assay was developed for the detection of CMV DNA in peripheral blood leukocytes. With this protocol, blood samples from 116 volunteer blood donors were investigated. None of these samples proved to be positive for CMV DNA. In contrast, CMV DNA was detected in 10 of 10 renal transplant patients early in the course of active CMV infection. It can be concluded that the CMV genome copy number in the peripheral blood leukocytes of healthy individuals is beyond the detection limit of current PCR technology.

Lesion development in Marburg's type of acute multiple sclerosis: from inflammation to demyelination

We report a patient who suffered from acute inflammatory CNS demyelination and underwent two consecutive diagnostic stereotactic brain biopsies during the early disease course. The first lesion was drawn 33 days after the onset of disseminated neurological symptoms. Macrophages and T lymphocytes diffusely infiltrated small vessel walls and the white matter. mRNA for tumor necrosis factor alpha (TNFa) and inducible nitric oxide synthase (iNOS) was abundantly expressed. Myelin sheaths were entirely preserved. The second biopsy 76 days later showed confluent demyelinating lesions with a diffuse infiltration of macrophages that were positive for myelin debris, activation markers and TNFa and iNOS mRNA. IgG and C9neo deposits were found along myelin sheaths. The patient had received intravenous immunoglobulins (IVIG) prior to biopsy. Findings from this single patient affirm that demyelination follows the migration of inflammatory cells from the circulation into the white matter with subsequent inflammation and demyelination. Inflammation alone may be sufficient to cause significant clinical deficits without demyelination. Inflammatory mediators such as TNFa and NO are involved at very early stages in the pathogenetic process. IVIG treatment may lead to the deposition of immunoglobulins and to the activation of the complement cascade, but the clinical relevance of this particular finding remains uncertain.

Bcl-2-expressing oligodendrocytes in Multiple sclerosis lesions

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system leading to selective destruction of myelin sheaths and/or oligodendrocytes. The immunological mechanisms responsible for myelin destruction and the primary target of the immune response have not yet been identified. Prior studies have reported a variable degree of oligodendrocyte preservation in actively demyelinating lesions. We have previously demonstrated that oligodendrocyte survival is heterogenous and varies between individual MS patients. Bcl‐2 belongs to the group of apoptosis‐associated proteins that protects cells from cell death. The purpose of the present study was to determine whether bcl‐2 expression is associated with oligodendrocyte preservation observed in some early MS lesions. Double immunocytochemistry was performed with antibodies against bcl‐2 and myelin oligodendrocyte glycoprotein (MOG) to identify bcl‐2–expressing oligodendrocytes within MS lesions from 43 patients. The number of bcl‐2–positive oligodendrocytes was determined depending on the lesion demyelinating activity and the disease course of the patients. The number of bcl‐2–expressing oligodendrocytes increased within demyelinating lesions compared to the periplaque white matter, with highest numbers in remyelinating lesions. There was a significant association between the presence of bcl‐2–positive oligodendrocytes and the presence of remyelination. The highest proportion of bcl‐2–positive oligodendrocytes was observed in a subgroup of patients with relapsing–remitting disease course. The expression of apoptosis‐associated proteins may contribute to oligodendrocyte preservation or loss in MS lesions. GLIA 28:34–39, 1999.