Neuroinflammation Screening in Immunotherapy Trials against Alzheimer's Disease

Due to side effects in the form of meningoencephalitis in the interrupted phase II AN1792 trial of active antiamyloid β(Aβ) immunization against Alzheimer's disease (AD), there has been concern that anti-Aβ immunization may cause destructive neuroinflammation. Here, we report on two patients fulfilling clinical AD criteria who were diagnosed with Lyme neuroborreliosis during screening before inclusion in anti-Aβ immunotherapy trials. The two cases illustrate the necessity of careful biochemical screening for neuroinflammatory/neuroinfectious conditions before an AD diagnosis is made and before clinical AD patients are included in trials of therapy that could impact the immune system. Should the two cases have been included and deteriorated, additional investigations might have led to the erroneous conclusion that therapy-induced meningoencephalitis had occurred

Cerebrospinal Fluid Analysis Should Be Considered in Patients with Cognitive Problems

Hepatologists assay liver enzymes and cardiologists structural heart proteins in serum to diagnose and monitor their patients. This way of thinking has not quite made it into the memory clinics yet, in spite of the availability of validated cerebrospinal fluid biomarkers for key pathological events in the brain in neurodegeneration. Here, we argue that a spinal tap should be considered in all patients who seek medical advice for memory problems and list the highly relevant clinical questions CSF analyses can address

Cerebrospinal Fluid Biomarker Levels as Markers for Nursing Home Placement and Survival Time in Alzheimer's Disease

BACKGROUND: Cerebrospinal fluid (CSF) biomarkers are associated with conversion from mild cognitive impairment to Alzheimer's disease (AD), but their predictive value for later end-points has been less evaluated with inconsistent results.OBJECTIVE: We investigated potential relationships between CSF amyloid-β1-42 (Aβ42), phosphorylated tau (P-tau), and total tau (T-tau) with time to nursing home placement (NHP) and life expectancy after diagnosis.METHODS: This prospective observational study included 129 outpatients clinically diagnosed with mild-to-moderate AD who underwent a lumbar puncture. The CSF biomarkers were analysed with xMAP technology. Dates of institutionalisation and death were recorded.RESULTS: After 20 years of follow-up, 123 patients (95%) were deceased. The participants with abnormal P-tau and T-tau (A+ T+ (N)+) died earlier than those with normal P-tau/abnormal T-tau (A+ T- (N)+) (mean, 80.5 vs. 85.4 years). Linear associations were demonstrated between lower Aβ42 and shorter time to NHP (p = 0.017), and higher P-tau and younger age at death (p = 0.016). No correlations were detected between survival after AD diagnosis and CSF biomarkers. In sex- and-age-adjusted Cox regression models, higher P-tau and T-tau were independent predictors of shorter lifespan after diagnosis. In multivariate Cox models, older age and lower baseline cognitive status, but not elevated tau, significantly precipitated both institutionalisation and death.CONCLUSION: These findings suggest that CSF biomarker levels plateau in the dementia phase of AD, which may limit their possible relationships with clinical end-points, such as NHP and survival time. However, the biomarkers reflect the central pathophysiologies of AD. In particular, pathologic tau is associated with more advanced disease, younger age at onset, and earlier death

Lessons from Multicenter Studies on CSF Biomarkers for Alzheimer's Disease

Several single-center studies have confirmed the usability of cerebrospinal fluid (CSF) biomarkers for the diagnosis of Alzheimer's disease (AD), even in early disease stages. Large scale multicenter studies have principally confirmed this, although such studies have also indicated the presence of significant intercenter and interlaboratory variations in biomarker measurements. Such variations may hamper the development of biomarkers and their introduction into clinical routine practice. Recently a quality control program run by the Alzheimer's Association was started in order to harmonize procedures of laboratories world-wide. This program provides both standardized guide lines and external control CSF samples, and will allow longitudinal evaluation of laboratory performance

Fluid biomarkers in Alzheimer's disease - current concepts

The diagnostic guidelines of Alzheimer's disease (AD) have recently been updated to include brain imaging and cerebrospinal fluid (CSF) biomarkers, with the aim of increasing the certainty of whether a patient has an ongoing AD neuropathologic process or not. The CSF biomarkers total tau (T-tau), hyperphosphorylated tau (P-tau) and the 42 amino acid isoform of amyloid beta (A beta 42) reflect the core pathologic features of AD, which are neuronal loss, intracellular neurofibrillary tangles and extracellular senile plaques. Since the pathologic processes of AD start decades before the first symptoms, these biomarkers may provide means of early disease detection. The updated guidelines identify three different stages of AD: preclinical AD, mild cognitive impairment (MCI) due to AD and AD with dementia. In this review, we aim to summarize the CSF biomarker data available for each of these stages. We also review results from blood biomarker studies. In summary, the core AD CSF biomarkers have high diagnostic accuracy both for AD with dementia and to predict incipient AD (MCI due to AD). Longitudinal studies on healthy elderly and recent cross-sectional studies on patients with dominantly inherited AD mutations have also found biomarker changes in cognitively normal at-risk individuals. This will be important if disease-modifying treatment becomes available, given that treatment will probably be most effective early in the disease. An important prerequisite for this is trustworthy analyses. Since measurements vary between studies and laboratories, standardization of analytical as well as pre-analytical procedures will be essential. This process is already initiated. Apart from filling diagnostic roles, biomarkers may also be utilized for prognosis, disease progression, development of new treatments, monitoring treatment effects and for increasing the knowledge about pathologic processes coupled to the disease. Hence, the search for new biomarkers continues. Several candidate biomarkers have been found in CSF, and although biomarkers in blood have been harder to find, some recent studies have presented encouraging results. But before drawing any major conclusions, these results need to be verified in independent studies