Prospective 10-year surveillance of human prion diseases in Japan.

We analysed the epidemiological data and clinical features of patients with prion diseases that had been registered by the Creutzfeldt-Jakob Disease Surveillance Committee, Japan, over the past 10 years, since 1999. We obtained information on 1685 Japanese patients suspected as having prion diseases and judged that 1222 patients had prion diseases, consisting of definite (n=180, 14.7%) and probable (n=1029, 84.2%) cases, except for dura mater graft-associated Creutzfeldt-Jakob disease which also included possible cases (n=13, 1.1%). They were classified into 922 (75.5%) with sporadic Creutzfeldt-Jakob disease, 216 (17.7%) with genetic prion diseases, 81 (6.6%) with acquired prion diseases, including 80 cases of dura mater graft-associated Creutzfeldt-Jakob disease and one case of variant Creutzfeldt-Jakob disease, and three cases of unclassified Creutzfeldt-Jakob disease (0.2%). The annual incidence rate of prion disease ranged from 0.65 in 1999 to 1.10 in 2006, with an average of 0.85, similar to European countries. Although methionine homozygosity at codon 129 polymorphism of the prion protein gene was reported to be very common (93%) in the general Japanese population, sporadic Creutzfeldt-Jakob disease in Japan was significantly associated with codon 129 homozygosity (97.5%), as reported in western countries. In sporadic Creutzfeldt-Jakob disease, MM1 type (Parchi's classification) is the most common, as in western countries. Among atypical sporadic Creutzfeldt-Jakob disease cases, the MM2 type appeared most common, probably related to the very high proportion of methionine allele in the Japanese population. As for iatrogenic Creutzfeldt-Jakob disease, only dura mater graft-associated Creutzfeldt-Jakob disease cases were reported in Japan and, combined with the data from previous surveillance systems, the total number of dura mater graft-associated Creutzfeldt-Jakob disease was 138, comprising the majority of worldwide dura mater graft-associated Creutzfeldt-Jakob disease patients. Regarding genetic prion diseases, the most common mutation of prion protein gene was V180I (41.2%), followed by P102L (18.1%), E200K (17.1%) and M232R (15.3%), and this distribution was quite different from that in Europe. In particular, V180I and M232R were quite rare mutations worldwide. Patients with V180I or M232R mutations rarely had a family history of prion diseases, indicating that a genetic test for sporadic cases is necessary to distinguish these from sporadic Creutzfeldt-Jakob disease. In conclusion, our prospective 10-year surveillance revealed a frequent occurrence of dura mater graft-associated Creutzfeldt-Jakob disease, and unique phenotypes of sporadic Creutzfeldt-Jakob disease and genetic prion diseases related to the characteristic distribution of prion protein gene mutations and polymorphisms in Japan, compared with those in western countries.

Establishment of a standard 14-3-3 protein assay of cerebrospinal fluid as a diagnostic tool for Creutzfeldt-Jakob disease.

Periodic sharp wave complexes observed on an electroencephalographic recording and the presence of a 14-3-3 protein in the cerebrospinal fluid (CSF) are both included in the diagnostic criteria for the Creutzfeldt-Jakob disease (CJD) supplied by the World Health Organization; however, the presence or absence of the 14-3-3 protein in the CSF is sometimes difficult to discern on a western blot because of equivocal bands. The goal of this study was to establish a standard 14-3-3 protein assay and to determine the threshold level of a 14-3-3 protein that can be assayed by western blot. We searched for the most suitable isoform of the 14-3-3 protein to test for in protein assays, and the most sensitive antibody among four antibodies with an affinity for 14-3-3. We measured the levels of all 14-3-3 isoforms in 112 patients with CJD and in 100 patients with other diseases. We compared the performances of four different antibodies. We carried out a semi-quantitative analysis of γ-isoform levels using the LAS 3000 system, which was capable of producing a digital image from the luminescence on a western blot. We determined that the most suitable isoform of the 14-3-3 protein for conducting a standardized assay was the γ-isoform. Among the four commercially available antibodies for this protein, the most sensitive and specific was 18647 (IBL, Japan). We report the high repeatability of the detection of the 14-3-3 protein by this antibody to the γ-isoform, showing that western blot can be used for semi-quantitative analysis.

In vivo detection of prion amyloid plaques using [(11)C]BF-227 PET.

PURPOSE: In vivo detection of pathological prion protein (PrP) in the brain is potentially useful for the diagnosis of transmissible spongiform encephalopathies (TSEs). However, there are no non-invasive ante-mortem means for detection of pathological PrP deposition in the brain. The purpose of this study is to evaluate the amyloid imaging tracer BF-227 with positron emission tomography (PET) for the non-invasive detection of PrP amyloid in the brain. METHODS: The binding ability of BF-227 to PrP amyloid was investigated using autoradiography and fluorescence microscopy. Five patients with TSEs, including three patients with Gerstmann-Sträussler-Scheinker disease (GSS) and two patients with sporadic Creutzfeldt-Jakob disease (CJD), underwent [(11)C]BF-227 PET scans. Results were compared with data from 10 normal controls and 17 patients with Alzheimer's disease (AD). The regional to pons standardized uptake value ratio was calculated as an index of BF-227 retention. RESULTS: Binding of BF-227 to PrP plaques was confirmed using brain samples from autopsy-confirmed GSS cases. In clinical PET study, significantly higher retention of BF-227 was detected in the cerebellum, thalamus and lateral temporal cortex of GSS patients compared to that in the corresponding tissues of normal controls. GSS patients also showed higher retention of BF-227 in the cerebellum, thalamus and medial temporal cortex compared to AD patients. In contrast, the two CJD patients showed no obvious retention of BF-227 in the brain. CONCLUSION: Although [(11)C]BF-227 is a non-specific imaging marker of cerebral amyloidosis, it is useful for in vivo detection of PrP plaques in the human brain in GSS, based on the regional distribution of the tracer. PET amyloid imaging might provide a means for both early diagnosis and non-invasive disease monitoring of certain forms of TSEs.

[Encephalomyelopathy due to vitamin B12 deficiency with seizures as a predominant symptom].

We report a 39-year-old man who developed seizures as a predominant symptom of vitamin B12 deficiency. About a month before admission to our hospital, he experienced flickering vision, and had generalized convulsive seizures about ten times a day. On admission, he presented with visual disturbance and paralysis of the left leg. Brain MRI revealed a tumor-like lesion in the medial side of the right frontal lobe. Follow-up MRI about 2 weeks after admission demonstrated multiple lesions in the periaqueduct, the medial side of the bilateral thalami, the bilateral frontal lobes, and the bilateral occipital lobes. After administration of antiepileptic drugs, his condition was well-controlled. Paralysis of his left leg was gradually improved, and abnormal findings on brain MRI disappeared except that in the right frontal lobe cortex, which was considered to be cortical laminar necrosis. 123I-IMP-SPECT showed hyperperfusion in the bilateral occipital lobes. About 3 months after the first admission, he was readmitted because of ataxic gait and numbness in the extremities. Laboratory tests revealed macrocytic anemia and vitamin B12 deficiency. Spinal MRI revealed typical findings of subacute combined degeneration. Brain MRI showed multiple new lesions in the bilateral dorsal sides of the medulla, cerebellar hemispheres, interthalamic adhesion, and left frontal cortex. After the initiation of vitamin B12 supplementary therapy, the symptoms were improved, and the abnormal MRI findings disappeared. Serum anti-gastric-parietal-cell antibody and anti-intrinsic-factor antibody were positive. 123I-IMP-SPECT demonstrated hypoperfusion in the bilateral occipital lobes, possibly reflecting visual disturbance. To the best of our knowledge, this is the first report indicating that vitamin B12 deficiency may insult various brain regions as well as the spinal cord with reversibility. Vitamin B12 deficiency should be also considered in the differential diagnosis of the causes of epilepsy.

Anti-aquaporin-4 antibody is involved in the pathogenesis of NMO: a study on antibody titre.

NMO-IgG is a disease-specific autoantibody for neuromyelitis optica (NMO) and its target antigen is aquaporin-4 (AQP4) water channel. Recently, we established a sensitive anti-AQP4 antibody assay using human AQP4-transfected cells, which appeared more sensitive than the original NMO-IgG assay. So far, there has been no large-scale study on anti-AQP4 antibody titre in NMO and related disorders. We tested 148 sera of patients with NMO, high-risk syndrome of NMO, multiple sclerosis (MS), clinically isolated syndrome suggestive of MS and miscellaneous diseases. We analysed the relation of anti-AQP4 antibody titres and clinical and laboratory parameters. The sensitivity of anti-AQP4 antibody assay was 91% (95% CI 79-100) for NMO and 85% (65-100) for high-risk syndrome, and the specificity was 100% (91-100) for NMO and high-risk syndrome, that is, none with the other disorders was positive. Among 21 anti-AQP4 antibody-positive cases whose NMO-IgG were tested, 15 were NMO-IgG-positive and 6 were NMO-IgG-negative. Higher anti-AQP4 antibody titres were associated with complete blindness and extensive or large cerebral lesions on MRI. The lengths of spinal cord lesions on MRI were positively correlated with the titres of anti-AQP4 antibody at the nadir of exacerbations. A few patients who had short (approx. one to two vertebral segments) spinal cord lesions on MRI were also seropositive with low anti-AQP4 antibody titres, but did have other clinical and MRI features of NMO. Anti-AQP4 antibody titres became lower after high-dose methylprednisolone, and a follow-up showed anti-AQP4 antibody titres remained low in relapse-free periods under immunosuppression. Cerebrospinal fluid (CSF)-anti-AQP4 antibody was detected when the serum-antibody titres exceeded 512x, at the ratio of 1 (CSF) to 500 (serum). Using a sensitive assay, the results of the present study suggest that NMO and high-risk syndrome may be essentially anti-AQP4 antibody-associated disorders, and that the anti-AQP4 antibody titres have significant clinical and immunological implications in NMO.

Two different clinical phenotypes of Creutzfeldt-Jakob disease with a M232R substitution.

OBJECTIVE: To describe the clinical features of Creutzfeldt-Jakob disease with a substitution of arginine for methionine (M232R substitution) at codon 232 (CJD232) of the prion protein gene (PRNP). PATIENTS AND METHODS: We evaluated the clinical and laboratory features of 20 CJD232 patients: age of onset, initial symptoms, duration until becoming akinetic and mute, duration until occurrence of periodic sharp and wave complexes on EEG (PSWC), MRI findings, and the presence of CSF 14-3-3 protein. Immunohistochemically, prion protein (PrP) deposition was studied. RESULTS: None of the patients had a family history of CJD. We recognized two clinical phenotypes: a rapidly progressive type (rapidtype) and a slowly progressive type (slow-type). Out of 20 patients, 15 became akinetic and mute, demonstrated myoclonus, and showed PSWC within a mean duration of 3.1, 2.4, and 2.8 months, respectively (rapid-type). Five showed slowly progressive clinical courses (slow-type). Five became akinetic and mute and four demonstrated myoclonus within a mean duration of 20.6 and 15.3 months, respectively, which were significantly longer than those in the rapid-type. Only one demonstrated PSWC 13 months after the onset. Diffuse synaptic-type deposition was demonstrated in four rapidtype patients, and perivacuolar and diffuse synaptic-type deposition in two, and diffuse synaptic-type deposition in one slow-type patient. Three of 50 suspected but non-CJD patients had the M232R substitution. CONCLUSIONS: Patients with CJD232 had no family history like patients with sCJD, and showed two different clinical phenotypes in spite of having the same PRNP genotype. More studies are needed to determine whether M232R substitution causes the disease and influences the disease progression.

[Clinical characteristics and laboratory findings in prion diseases].

Acutely progressing dementia, generalized myoclonus, and periodic synchronous discharge (PSD) on EEG are thought to be characteristic features of Creutzfeldt-Jakob disease (CJD). However, recent surveillance studies in European countries and Japan have revealed several uncommon variants that run relatively long clinical course, demonstrate atypical myoclonus, and show no PSD. Brain specific proteins such as 14-3-3 protein, tau protein, and neuron specific enolase (NSE) are detected in the CSF of CJD patients. Clinical features and laboratory findings of sporadic CJD are related well to the combination of polymorphism at codon 129 of prion protein gene(PRNP) (Methionine/Methionine, Methionine/Valine, and Valine/Valine) and type of pathogenic prion protein (type 1 and type 2). Those of genetic prion disease depend on pathogenic mutation in PRNP. Positive rates of PSD and 14-3-3 protein in the CSF differ among subtypes of sporadic CJD and genetic prion diseases. Diffusion-weighted MRI is very useful for an early clinical diagnosis of CJD and some subtypes show their own characteristic findings.

14-3-3 protein levels and isoform patterns in the cerebrospinal fluid of Creutzfeldt-Jakob disease patients in the progressive and terminal stages.

To elucidate the diagnostic value and to establish the 14-3-3 isoform patterns in the cerebrospinal fluid (CSF) of Creutzfeldt-Jakob disease (CJD) patients, we analysed the 14-3-3 isoform patterns in the CSF of 11 CJD patients using the Western immunoassay technique. 14-3-3 protein was detected in the CSF of seven CJD patients in the progressive stage, but not in four patients in the terminal stages whose brains were severely atrophied. The amount of 14-3-3 protein measured semi-quantitatively in the CSF was correlated with that of neuron-specific enolase measured using an enzyme-linked immunosorbent assay in the same CSF. CJD patients showed five dominant 14-3-3 isoforms, gamma, epsilon, zeta, eta and beta, but 14-3-3 tau, which mainly originates from T lymphocytes, was not detected. 14-3-3 protein is released into the CSF as a consequence of the extensive and rapid destruction of the brain, and the presence of the five isoforms enhances the diagnostic value of 14-3-3 protein in the progressive stage.

Transethmoidal intranasal meningoencephalocele in an adult with recurrent meningitis.

Intranasal meningoencephalocele is a rarely encountered congenital malformation. We report a case of transethmoidal intranasal meningoencephalocele in a 52-year old man with recurrent purulent meningitis. After treatment of the acute meningitis, frontal craniotomy followed by the removal of the stalk of the meningoencephalocele and repair of the bony defect was successfully performed. He has had no further meningitis or CSF rhinorrhea post-operatively. Detailed neuroradiological examination and appropriate surgical treatment are important to prevent fatal neurological complications of intranasal meningoencephalocele.

Periodic episodes of aphasia as an unusual manifestation of partial status epilepticus.

Recurrent episodes of aphasia due to partial status epilepticus is an uncommon clinical entity. We report here a 78-year-old-woman with episodic aphasia which occurred periodically. During the ictal period, she was conscious, but had difficulty in speech and could not comprehend verbal commands. The ictal EEG showed continuous spike and sharp waves over the left frontotemporal area. After the administration of antiepileptic drugs, her language activity returned to near the baseline level and the epileptic discharges were significantly reduced. Nonconvulsive partial status epilepticus should be considered in the differential diagnosis of recurrent aphasia, even if the symptoms occur periodically.

[Toxoplasma encephalitis in a patient receiving cyclosporine monotherapy for Behçet disease].

We report a 44-year-old woman with toxoplasma encephalitis that occurred during cyclosporine monotherapy for Behçet disease. She had been treated with cyclosporine for 8 years. She experienced headache and, nausea, and then consciousness disturbance developed. Brain MRI showed high-signal intensity lesions on T1-weighted MRI with Gd-enhancement in the left temporoparietal lobe, right thalamus and right frontal and temporal lobes. The pathological examination of the biopsied brain specimens suggested toxoplasma encephalitis. She improved rapidly after the administration of antibiotics for toxoplasma gondii. Anti-toxoplasma specific protein antibodies were positive in the serum and CSF, supporting a diagnosis of acute toxoplasmosis. Toxoplasma encephalitis due to cyclosporine mono-therapy has not been reported yet. The measurement of anti-toxoplasma specific protein antibodies may be useful for the early, accurate diagnosis of toxoplasmosis.

Th1/Th2 balance and HTLV-I proviral load in HAM/TSP patients treated with interferon-alpha.

We studied the immunological and virological effects of interferon-alpha (IFN-alpha) therapy in nine patients with HTLV-I-associated myelopathy (HAM/TSP). After therapy, the percentages of CCR5+ cells in CD4+ cells significantly decreased in the cerebrospinal fluid as well as blood. The therapy also significantly lowered the intracellular IFN-gamma+/interleukin-4+ T-cell ratio in blood. Those helper T-cell type 1 (Th1)-related responses tended to be higher and reduce more evidently following therapy in three patients who clinically improved. Also, all the three patients had one or more HTLV-I copies in five blood mononuclear cells. These results suggest that IFN-alpha suppresses Th1 responses in HAM/TSP and that the patients with higher Th1 immunity and proviral loads may be responders of the therapy. Larger-scale studies are needed to confirm the findings.

Interferon-alpha significantly reduces cerebrospinal fluid CD4 cell subsets in HAM/TSP.

We, for the first time, analyzed T cell and natural killer (NK) cell subsets in the cerebrospinal fluid (CSF) in nine patients with human T-lymphotropic virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) treated with interferon-alpha (IFN-alpha). The CD4/CD8 ratio in CSF was significantly lower after the therapy, which is mainly attributable to the significant reduction in CD4+ cells, especially CD25+CD4 and CD45RO+CD4 cell subsets. Meanwhile, NK, natural T and NKT cell subsets in the CSF remained unchanged. There was no CSF lymphocyte subset significantly associated with the clinical efficacy of IFN-alpha in this small-scale study, and more patients should be analyzed to ascertain the link.

Inflammatory demyelinating disease mimicking malignant glioma.

UNLABELLED: The differential diagnosis between inflammatory demyelinating disease and malignant glioma is difficult based only on neuroimaging methods. METHODS: Four patients with inflammatory demyelinating disease who presented with clinical and neuroimaging findings strongly suggestive of malignant glioma were examined. RESULTS: MRI showed a mass lesion with prolonged T1 and T2 values and gadolinium enhancement in all cases. Proton MR spectroscopy and (201)Tl SPECT showed findings supportive of the diagnosis of malignant glioma in all cases. However, surgical biopsy revealed inflammatory demyelinating disease. After the diagnosis, 2 patients were treated by steroid administration and 2 were just observed. The gadolinium enhancement of all lesions decreased and finally disappeared. CONCLUSION: Such cases illustrate the importance of considering a demyelinating lesion in the differential diagnosis of a mass lesion. The difficulties encountered in establishing the correct diagnosis of inflammatory disease are related to the variations in the radiologic appearance, which require exclusion of gliomas or other brain tumors by surgical biopsy before the therapeutic strategy can be selected.

Conspicuity and evolution of lesions in Creutzfeldt-Jakob disease at diffusion-weighted imaging.

BACKGROUND AND PURPOSE: Diffusion-weighted imaging can disclose distinct hyperintense lesions in Creutzfeldt-Jakob disease (CJD). However, these findings and chronologic changes of CJD at diffusion-weighted imaging have not been fully investigated. Our purpose was to assess the diagnostic value of diffusion-weighted imaging in depicting CJD-related lesions and in tracking the evolution of these lesions. We also compared the sensitivity of diffusion-weighted imaging in depicting CJD-related lesions to that of fluid-attenuated inversion recovery (FLAIR) imaging. METHODS: We reviewed findings in 13 patients with a diagnosis of CJD who underwent MR imaging, including diffusion-weighted imaging. Nine patients were initially examined within 4 months of onset of symptoms (early stage), and eight were examined 4 months or later (late stage). We evaluated four items: 1) distribution of lesions at diffusion-weighted imaging, 2) conspicuity of lesions at diffusion-weighted imaging and FLAIR imaging, 3) chronologic changes in lesions at diffusion-weighted imaging, and 4) chronologic changes in lesions revealed by apparent diffusion coefficient (ADC) maps. RESULTS: Patients had striatal lesions or cerebral cortical lesions or both. The thalamus was involved in only one patient, and the globus pallidus was spared in all patients. The sensitivity of diffusion-weighted imaging in depicting lesions was superior or at least equal to that of FLAIR imaging. Hyperintense lesions at diffusion-weighted imaging changed in extent and intensity over time. Unlike infarction, lesional ADC decreased for 2 weeks or longer. CONCLUSION: The progressively hyperintense changes in the striata and cerebral cortices at diffusion-weighted imaging are considered characteristic of CJD. Diffusion-weighted imaging may be useful for the early diagnosis of CJD.

Familial inclusion body myositis: a report on two Japanese sisters.

Familial occurrence of inclusion body myositis is extremely rare, and only a few cases in Western countries have been reported. In these reports, a strong association of this disease with DR3 (DRB1*0301/0302) and the efficacy of immunosuppressants suggested that an immune pathomechanism is involved in the disease. We, for the first time, report two Japanese sisters who suffered myopathy clinicopathologically similar to inclusion body myositis. One sister received corticosteroid and azathioprine and the therapy relieved dysphagia. Both of our patients had DR15(2)/4 (DRB1*1502/0405), suggesting a distinct genetic association with the disease in the Japanese population.

[A case of Marchiafava-Bignami disease: serial changes with diffusion-weighted MR imaging].

We report a 34-year-old man who presented with alcohol-withdrawal delirium. In the early phase, diffusion-weighted MR imaging demonstrating a high intensity area in the corpus callosum, indicating Marchiafava-Bignami disease. T2-weighted MR imaging did not clearly show the lesion. He was treated and completely recovered in terms of clinical state and MRI findings. Although historically the most of Marchiafava-Bignami disease was not cured, it seems that the lesion is reversible by management in the early stage. We propose that diffusion-weighted MR imaging is useful for the early detection of Marchiafava-Bignami disease.

[Laboratory and imaging studies for the diagnosis of prion disease].

We evaluated the diagnostic sensitivity of periodic synchronous discharge (PSD) in EEG, brain specific proteins in CSF such as neuron specific enolase (NSE), 14-3-3 protein, and tau protein, and imaging studies performed by T2-weighted MRI (T2I) and diffusion-weighted MRI (DWI). 36 patients with a mean age of 68.6 years were enrolled. Their diagnostic levels were as follows: seven were definite, 28 were possible, and one was probable who had a disease-specific point mutation of V180I. The diagnostic sensitivities of PSD, NSE, 14-3-3 protein, tau protein, DWI, and T2I were 50% (N = 36), 70% (N = 30), 80.8% (N = 26), 87.5% (N = 16), 92.3% (N = 26), and 42.3% (N = 26), respectively. DWI could revealed the CJD-related lesions earlier than the appearance of PSD. DWI revealed the lesions even in the patients who did not show PSD. For the diagnosis of CJD, DWI and either 14-3-3 protein or tau protein are useful. Using western blot, we detected the protease-resistant PrP in the urine of 11 of 15 CJD patients. We also detected it in three of 25 disease control patients. Differing from previous reports, the detection of a protease-resistant PrP was not specific to CJD patients. However, the sensitivity was 73.3% and the specificity was 88.9%.

[MR spectroscopy findings of a case of intravascular malignant lymphoma: usefulness for differential diagnosis].

We report a 49-year-old previously healthy woman with acute onset of decrease in attention, dysarthria and ataxia, accompanied by drowsiness. On admission, there were cloudness of consciousness, hallucination and left hemiparesis. Cerebrospinal fluid study revealed a cell count of 1/mm3, and the cytology was class I with a slight increase in protein. MRI of the brain performed on admission showed multiple gadolinium-enhanced lesions with a T2 weighted high intensity area in the cerebral white matter. At first the patient was diagnosed as acute disseminated encephalomyelitis (ADEM), and treated with methylprednisolon pulse therapy. Soon after, she showed transient clinical improvement, but her condition soon worsened. MR spectroscopy revealed elevated choline peak, decreased NAA peak and lactate peak, which indicated a neoplastic lesion. The brain biopsy disclosed diffuse intravascular lymphoma (IVL). MRS was useful in the differential diagnosis of IVL from ADEM.