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. 2013 Apr 23;8(4):e62101.
doi: 10.1371/journal.pone.0062101. Print 2013.

Blood levels of glial fibrillary acidic protein (GFAP) in patients with neurological diseases

Christoph A Mayer  1 , Robert Brunkhorst, Marion Niessner, Waltraud Pfeilschifter, Helmuth Steinmetz, Christian Foerch
Affiliations

Blood levels of glial fibrillary acidic protein (GFAP) in patients with neurological diseases

Christoph A Mayer et al. PLoS One. .

Abstract

Background and purpose: The brain-specific astroglial protein GFAP is a blood biomarker candidate indicative of intracerebral hemorrhage in patients with symptoms suspicious of acute stroke. Comparably little, however, is known about GFAP release in other neurological disorders. In order to identify potential "specificity gaps" of a future GFAP test used to diagnose intracerebral hemorrhage, we measured GFAP in the blood of a large and rather unselected collective of patients with neurological diseases.

Methods: Within a one-year period, we randomly selected in-patients of our university hospital for study inclusion. Patients with ischemic stroke, transient ischemic attack and intracerebral hemorrhage were excluded. Primary endpoint was the ICD-10 coded diagnosis reached at discharge. During hospital stay, blood was collected, and GFAP plasma levels were determined using an advanced prototype immunoassay at Roche Diagnostics.

Results: A total of 331 patients were included, covering a broad spectrum of neurological diseases. GFAP levels were low in the vast majority of patients, with 98.5% of cases lying below the cut-off that was previously defined for the differentiation of intracerebral hemorrhage and ischemic stroke. No diagnosis or group of diagnoses was identified that showed consistently increased GFAP values. No association with age and sex was found.

Conclusion: Most acute and chronic neurological diseases, including typical stroke mimics, are not associated with detectable GFAP levels in the bloodstream. Our findings underline the hypothesis that rapid astroglial destruction as in acute intracerebral hemorrhage is mandatory for GFAP increase. A future GFAP blood test applied to identify patients with intracerebral hemorrhage is likely to have a high specificity.

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Conflict of interest statement

Competing Interests: The authors have read the journal's policy and have the following conflicts: C. Mayer received travel grants from Novartis Pharma, Biogen Idec and Merck Serono. C. Mayer received research funding from Novartis Pharma. C. Foerch, designated as inventor in the following European patent application: Use of GFAP for identification of intracerebral hemorrhage (patent application 03021571.9) C. Foerch received honoraria for participation in advisory boards at Roche Diagnostics. M. Niessner is employed at Roche Diagnostics. This does not alter the authors' adherence to all the PLOS ONE policies on sharing data and materials.

Figures

Figure 1
Figure 1. Patients are grouped according to discharge diagnosis (“ICD” = International Classification of Diseases).
“n” depicts the number of patients per diagnosis. “n<0.05” displays the number of patients per diagnosis with GFAP values below the lower detection limit of the used immunoassay. The remaining values (those above the lower detection limit) are displayed as individual values in the graph. Individual patients with increased GFAP values are easy to recognize. Mean GFAP values and standard deviation (SD) are also provided for each diagnosis. The diagnoses with the three highest mean GFAP values are labelled in red. * = GFAP value of one sample is missing. ** = Results of the BE FAST study for comparison .
See this image and copyright information in PMC

References

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