Progressive multifocal leukoencephalopathy after allogeneic stem cell transplantation: Case report and review of the literature.

Progressive multifocal leukoencephalopathy (PML) is a rare, yet typically fatal complication of allogeneic stem cell transplantation. It is caused by reactivation of the John Cunningham (JC) virus in an immunocompromised host. This report describes an unfortunate case of PML in a recipient of an allogeneic stem cell transplant for acute myelogenous leukemia. The JC virus was undetectable in the patient's cerebrospinal fluid by polymerase chain reaction (PCR); however, a positive diagnosis was made after a brain biopsy. This and other published cases demonstrate that recipients of allogeneic stem cells can develop PML. Moreover, early diagnosis of the disease is often difficult and, as demonstrated in this case, screening with PCR does not appear to have strong diagnostic significance. With no effective treatment presently available, restoration of immune function is the only intervention that can affect prognosis. Further prospective studies are needed to understand the pathophysiology and treatment of this disease.

Imaging Manifestations of Creutzfeldt-Jakob Disease and Case Series.

Sporadic Creutzfeldt-Jakob disease (CJD) is the most common prion disease, resulting in rapid neurocognitive decline, and is universally lethal. CJD has a confounding clinical presentation with similarities which overlap with many other neurodegenerative disorders. Brain biopsy is the current gold standard; however, less-invasive initial screening tests are also utilized. These include brain magnetic resonance imaging (MRI), electroencephalography (EEG), and cerebrospinal fluid (CSF) laboratory studies. Five patients presented to our facility with varying levels of nonspecific cognitive impairment and movement disorders. CJD was initially suggested after review of each patient's brain MRI. The T2-weighted fluid attenuation inversion recovery and diffusion-weighted images in each case demonstrated varied classic patterns of signal abnormality involving the cortex, basal ganglia, thalami, and brainstem. EEG and CSF studies were confirmatory in three and four patients, respectively (EEG not performed in one patient). One death occurred two months after initial presentation, and the other four patients were transferred to hospice three, four, nine, and 20 months after initial presentation. Radiological evaluation is an invaluable component of the workup for nonspecific neurodegenerative disorders because brain MRI may suggest the initial diagnosis of CJD, as demonstrated in our presented cases. Familiarity with the spectrum of classic MRI findings suggestive of sporadic CJD can improve radiologists' role in early detection of the most common prion disease. Clinicians may benefit from understanding the utility of the newer CSF laboratory studies (Real-time quaking-induced conversion, T-tau, and 14-3-3 protein), which are far less invasive than the gold standard of brain biopsy. Early diagnosis can help save medical resources and guide clinicians to form appropriate plans of care with the patient and family.

Novel forms of neurofascin 155 in the central nervous system: alterations in paranodal disruption models and multiple sclerosis.

Stability of the myelin-axon unit is achieved, at least in part, by specialized paranodal junctions comprised of the neuronal heterocomplex of contactin and contactin-associated protein and the myelin protein neurofascin 155. In multiple sclerosis, normal distribution of these proteins is altered, resulting in the loss of the insulating myelin and consequently causing axonal dysfunction. Previously, this laboratory reported that mice lacking the myelin-enriched lipid sulphatide are characterized by a progressive deterioration of the paranodal structure. Here, it is shown that this deterioration is preceded by significant loss of neurofascin 155 clustering at the myelin paranode. Interestingly, prolonged electrophoretic separation revealed the existence of two neurofascin 155 bands, neurofascin 155 high and neurofascin 155 low, which are readily observed following N-linked deglycosylation. Neurofascin 155 high is observed at 7 days of age and reaches peak expression at one month of age, while neurofascin 155 low is first observed at 14 days of age and constantly increases until 5 months of age. Studies using conditional neurofascin knockout mice indicated that neurofascin 155 high and neurofascin 155 low are products of the neurofascin gene and are exclusively expressed by oligodendrocytes within the central nervous system. Neurofascin 155 high is a myelin paranodal protein while the distribution of neurofascin 155 low remains to be determined. While neurofascin 155 high levels are significantly reduced in the sulphatide null mice at 15 days, 30 days and 4 months of age, neurofascin 155 low levels remain unaltered. Although maintained at normal levels, neurofascin 155 low is incapable of preserving paranodal structure, thus indicating that neurofascin 155 high is required for paranodal stability. Additionally, comparisons between neurofascin 155 high and neurofascin 155 low in human samples revealed a significant alteration, specifically in multiple sclerosis plaques.