Cerebrospinal fluid in Creutzfeldt–Jakob disease

Calmodulin level is significantly increased in the cerebrospinal fluid of patients with sporadic Creutzfeldt-Jakob disease

BACKGROUND AND PURPOSE

Human prion diseases (PrDs) are a group of fatal and transmissible neurodegenerative disorders that are diagnosed definitively in post mortem brains. Calmodulin (CaM) is a ubiquitous calcium-binding protein. Increased brain CaM level has been reported in prion-infected rodent models and some scrapie-infected cells. However, the putative alteration of CaM in cerebrospinal fluid (CSF) of human PrDs is uncertain. Here, we try to figure out the profiles of CSF CaM in sporadic Creutzfeldt-Jacob disease.

METHODS

Cerebrospinal fluid samples of 40 Chinese patients with probable sporadic Creutzfeldt-Jacob disease (sCJD) and 40 cases without sCJD (non-PrDs) were recruited in this study. The presence of CaM in the CSF was assessed by Western blot, while total tau levels were measured using an enzyme-linked immunosorbent assay kit. In addition, the presence of CaM in another CSF panel consisting of 30 definite sCJD cases and 30 non-PrD cases was evaluated using CaM-specific Western blot analysis.

RESULTS

Cerebrospinal fluid CaM positivity was observed in 28/40 cases of probable sCJD and in 9/40 non-PrD cases. The CSF tau levels in the probable sCJD cases were markedly higher than those in the non-PrD cases. Logistic regression established a significant correlation between CSF CaM signal and total CSF tau level. Similar results were observed in the panel of cases with definite sCJD: the rates of CSF CaM positivity in the definite sCJD cases and the non-PrD cases were 22/30 and 6/30, respectively.

CONCLUSIONS

Although CSF CaM positivity might not be a sCJD-specific phenomenon, a significantly high rate of CaM-positive CSF in sCJD cases, especially in those with high CSF tau levels, rendered it a valuable diagnostic biomarker for sCJD.

Detection of Pathognomonic Biomarker PrPSc and the Contribution of Cell Free-Amplification Techniques to the Diagnosis of Prion Diseases

Transmissible spongiform encephalopathies or prion diseases are rapidly progressive neurodegenerative diseases, the clinical manifestation of which can resemble other promptly evolving neurological maladies. Therefore, the unequivocal ante-mortem diagnosis is highly challenging and was only possible by histopathological and immunohistochemical analysis of the brain at necropsy. Although surrogate biomarkers of neurological damage have become invaluable to complement clinical data and provide more accurate diagnostics at early stages, other neurodegenerative diseases show similar alterations hindering the differential diagnosis. To solve that, the detection of the pathognomonic biomarker of disease, PrP^Sc, the aberrantly folded isoform of the prion protein, could be used. However, the amounts in easily accessible tissues or body fluids at pre-clinical or early clinical stages are extremely low for the standard detection methods. The solution comes from the recent development of in vitro prion propagation techniques, such as Protein Misfolding Cyclic Amplification (PMCA) and Real Time-Quaking Induced Conversion (RT-QuIC), which have been already applied to detect minute amounts of PrP^Sc in different matrixes and make early diagnosis of prion diseases feasible in a near future. Herein, the most relevant tissues and body fluids in which PrP^Sc has been detected in animals and humans are being reviewed, especially those in which cell-free prion propagation systems have been used with diagnostic purposes.

Profiles of 14-3-3 and Total Tau in CSF Samples of Chinese Patients of Different Genetic Prion Diseases

Background

The abnormal alterations of proteins 14-3-3 and tau in cerebrospinal fluid (CSF) are widely used for the diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD), while the situations of CSF biomarkers in genetic prion diseases (gPrDs), particularly in Chinese gPrDs patients, have not been well documented.

Methods

Here, with the help of commercial 14-3-3 and total tau ELISA kits, we evaluated the levels of proteins 14-3-3 and tau in the CSF samples of 140 Chinese patients of 14 different types of gPrDs.

Results

We found that CSF 14-3-3 ELISA values in the patients with P102L GSS and D178N FFI were remarkably low, while those in the patients with T188K, E196A, and E200K gCJD were relatively high. Linear correlation assays identified a positive correlation between positive rate in Western blot (WB) and ELISA values of CSF 14-3-3. ELISA assays for total tau in CSF samples identified relatively high levels in the cases of T188K, E196A, and E200K gCJD (median: 133840.81, 159992.80, and 153342.92 AU/ml), but relatively low levels in those of P102L GSS and D178N FFI (median: 64397.77 and 43856.79 AU/ml).

Conclusion

These data illustrate heterogeneous profiles of CSF 14-3-3 and tau in various types of gPrDs, depending on the differences in the mutations in PRNP.

E200k Familial Creutzfeldt-Jakob Disease Presenting with Subacute Multiple Cranial Neuropathy

Unusual clinical presentations in patients with E200K familial Creutzfeldt-Jakob Disease (fCJD) have been rarely reported. Herein, we described a case of E200K fCJD presenting with subacute cranial multiple neuropathy, initially suspected to be paraneoplastic or due to a leptomeningeal carcinomatosis, considering the neoplastic comorbidity of the patient. Surprisingly, brain MRI was highly suggestive of CJD. Brain histological examination confirmed the diagnosis. Genetic tests led to the definite diagnosis of E200K fCJD. To the best of our knowledge, the current case provides the first report of a histologically-confirmed E200K fCJD starting with cranial multiple neuropathy and may widen the spectrum of the clinical variability of CJD, also in its genetic variant. Unusual presentations may lead, as in this case, to incorrect diagnostic hypothesis and unuseful therapeutic attempts in the first phase of the diagnostic process. Also in the genetic variant of CJD, brain MRI demonstrated a very high sensitivity to detect the typical abnormalities since the earliest phases of the disease.

White paper by the Society for CSF Analysis and Clinical Neurochemistry: Overcoming barriers in biomarker development and clinical translation

Body fluid biomarkers have great potential for different clinical purposes, including diagnosis, prognosis, patient stratification and treatment effect monitoring. This is exemplified by current use of several excellent biomarkers, such as the Alzheimer’s disease cerebrospinal fluid (CSF) biomarkers, anti-neuromyelitis optica antibodies and blood neurofilament light. We still, however, have a strong need for additional biomarkers and several gaps in their development and implementation should be filled. Examples of such gaps are i) limited knowledge of the causes of neurological diseases, and thus hypotheses about the best biomarkers to detect subclinical stages of these diseases; ii) the limited success translating discoveries obtained by e.g. initial mass spectrometry proteomic low-throughput studies into immunoassays for widespread clinical implementation; iii) lack of interaction among all stakeholders to optimise and adapt study designs throughout the biomarker development process to medical needs, which may change during the long period needed for biomarker development.

The Society for CSF Analysis and Clinical Neurochemistry (established in 2015) has been founded as a concerted follow-up of large standardisation projects, including BIOMARKAPD and SOPHIA, and the BioMS-consortium.

The main aims of the CSF society are to exchange high level international scientific experience, to facilitate the incorporation of CSF diagnostics into clinical practice and to give advice on inclusion of CSF analysis into clinical guidelines. The society has a broad scope, as its vision is that the gaps in development and implementation of biomarkers are shared among almost all neurological diseases and thus they can benefit from the activities of the society.