Joseph Menonna

Cell death and birth in multiple sclerosis brain

The hallmark of the brain pathology in multiple sclerosis is the white matter plaque, characterized by myelin destruction and oligodendrocyte loss. To examine the role that cell death plays in the development of MS lesions, we used the in situ TUNEL technique, a method that sensitively detects DNA fragmentation associated with death at the single cell level. We found that patchy areas within acute MS lesions have massive numbers of inflammatory and glial cells undergoing cell death. The punched out areas of some long-standing chronic lesions also had labeled glial cells showing that the attack was not a single event. Immunocytochemical identification of the dying cells with glial specific marker co-labeling showed that 14-40% were the myelin-sustaining oligodendroglial cell. Confocal microscopic evaluation of fluorescein-labeled TUNEL positive cells revealed nuclei with morphologic characteristics of apoptosis, and electrophoresed MS brain DNA produced a ladder characteristic of apoptotic DNA cleavage confirming that substantial numbers of labeled cells, but not necessarily all, were dying by apoptotic mechanisms rather than cell necrosis. Companion studies using a marker for cell proliferation on MS lesions revealed that unexpectedly large populations of perivascular inflammatory cells and parenchymal glial cells had entered the cell proliferation cycle. These findings establish that two opposing glial cell responses - relentless cell death and coincident brisk cellular proliferation - are important features of MS pathology. In the end, however, glial cell loss prevails, and we suspect apoptosis may be the critical death mechanism responsible for the depletion of myelin observed in this condition.

Platelet‐derived growth factor‐α receptor‐positive oligodendroglia are frequent in multiple sclerosis lesions

Platelet‐derived growth factor (PDGF) ligand is a potent glial cell mitogen. When its cognate receptor (PDGF‐αR) is expressed on oligodendroglial lineage cells, such cells are considered capable of division, and the receptor thus serves as a phenotypic marker for oligodendrocyte precursor cells. Here we identify using immunohistochemistry a considerably enlarged, PDGF‐αR‐expressing oligodendrocyte cell population within multiple sclerosis (MS) white matter lesions compared to control brains. Numerous PDGF‐αR‐positive oligodendroglia also colabel heavily with the nuclear cell proliferation marker antibody Ki‐67. Our finding of large numbers of proliferating oligodendroglia in MS brains expressing up‐regulated PDGF‐αR suggests that these progenitor‐like cells represent an important source of regenerating cells for the healing MS lesion.

Measles virus L protein evidences elements of ancestral RNA polymerase

We have determined the nucleotide sequence of the measles virus (MV) L gene using a cDNA library encompassing the entire MV genome (J. Crowley et al. (1987) Intervirology, 28, 65-77). The L gene is 6639 nucleotides in length, and contains a single long open reading frame that could code for a protein of 247,611 kDa. Both the L gene and in particular the predicted L protein of MV bear substantial homology to their counterparts in Sendai virus and Newcastle disease virus, suggesting that the multifunctional nature of paramyxovirus L proteins imposes strong evolutionary constraints. The predicted MV L protein also contains distinct elements of a postulated ancestral RNA polymerase.

Cytomegalovirus cornplement fixation antibody in Guillain‐Barré syndrome

Cytomegalovirus, measles, and adenovirus antibodies were measured in the sera of 92 Guillain-Barré patients and 120 controls. Thirty patients (33 percent) had markedly elevated levels of complement-fixing antibody to cytomegalovirus and in 21, a fourfold or more alteration in titer was demonstrated. Diagnostic falls in titer were seen in most instances and no significant elevation to the other viral agents was found. The serologic findings reported here suggest that cytomegalovirus may be a common agent involved in the pathogenesis of the Guillain-Barré syndrome.

HERPES SIMPLEX VIRUS‐IgM SPECIFIC ANTIBODIES IN GUILLAIN‐BARRÉ SYNDROME AND ENCEPHALITIS

Herpes simplex virus (HSV) has been associated with a variety of inflammatory neurologic disorders. Recently we studied a patient with Guillain‐Barré syndrome (GBS) following acute herpes vaginalis infection. Since IgM virus‐specific antibody is thought to be a reliable indicator of acute viral infection, we employed a 2‐h serologic assay for serum IgM antibodies to HSV using an indirect immunofluorescent technique. This patient demonstrated high serum IgM titers to HSV type 2 during the acute phase of her neurologic syndrome. The titer dropped substantially as convalescence progressed. A search for similar elevations in HSV‐IgM specific antibody was made on sera from more than 70 other GBS patients. No other significant IgM antibody titers to either HSV type 1 or type 2 were found in this GBS series and a large number of neurologic controls. However, sera from two patients with a presumptive diagnosis of acute herpes encephalitis based on clinical and cerebrospinal fluid findings were positive, showing high titers in our test. The results of this study suggest that associated acute HSV infection is uncommon in GBS and an immunofluorescent seroassay of the type reported here may be a valuable noninvasive technique enabling the clinical laboratory to rapid confirm a diagnosis of herpes encephalitis.

Serologic abnormalities in multiple sclerosis

Acute phase reactants. In the search for an even more sensitive gauge of disease activity, we measured serum levels of the fourth component of the classical complement pathway (C4) in MS patients. Serum levels of C4 were determined by radial immunodiffusion in 90 MS patients manifesting a wide spectrum of disease activity and neurologic impairment. Twentythree patients had significantly elevated levels of C4 when compared to normal controls. At least 16 of these patients had experienced a recent exacerbation of MS or had rapidly progressing neurologic deficits. C3 proactivator, as well as the acute phase reactants C-reactive protein and orosomucoid, were found to be significantly increased in most of these patients, whereas another component of the classical complement pathway, C3, was rarely abnormal. These findings suggest that C4 acts as an acute phase reactant in some exacerbations of MS and that serial measurements may be of value in assessing disease activity in certain patients.

Rapid fluorometric assay for cerebrospinal fluid immunoglobulin G.

Using a new quantitative immunofluorometric procedure, we measured cerebrospinal fluid immunoglobulin G levels in 59 patients and compared the results with values obtained by the most precise currently available method—the immunoprecipitin method of Kabat—and a radial immunodiffusion technique. The absolute immunoglobulin G values determined by the fluorometric assay correlated closely with the other methods. This technique offers several advantages over most conventional techniques for measuring low levels of immunoglobulin G: (1) Small, drop-sized (5 to 10 μI) samples of cerebrospinal fluid are used, (2) a large number of samples can be tested, (3) the range of sensitivity is sufficiently wide that cerebrospinal fluid and serum levels can be determined simultaneously, and (4) the technique is fast, requiring 3.5 hours to perform. The fluorometric method is rapid, reproducible, and easy. Its suitability for laboratories engaged in the measurement of cerebrospinal fluid immunoglobulin G appears promising.