Phosphorylated neurofilament heavy subunit (pNF-H) in peripheral blood and CSF as a potential prognostic biomarker in amyotrophic lateral sclerosis
- Kevin B Boylan1,
- Jonathan D Glass2,
- Julia E Crook3,
- Cui Yang4,
- Colleen S Thomas3,
- Pamela Desaro1,
- Amelia Johnston1,
- Karen Overstreet1,
- Crystal Kelly2,
- Meraida Polak2,
- Gerry Shaw4
- 1Department of Neurology, Mayo Clinic, Jacksonville, Florida, USA
- 2Department of Neurology, Emory University School of Medicine, Atlanta, Georgia, USA
- 3Biostatistics Unit, Mayo Clinic, Jacksonville, Florida, USA
- 4Department of Neuroscience, McKnight Brain Institute, University of Florida College of Medicine, Gainesville, Florida, USA
- Correspondence to Dr K B Boylan, Department of Neurology, Mayo Clinic, Jacksonville, FL 32224, USA;
- Received 26 July 2012
- Revised 12 September 2012
- Accepted 4 October 2012
- Published Online First 31 October 2012
Background The phosphorylated neurofilament heavy subunit (pNF-H), a major structural component of motor axons, is a promising putative biomarker in amyotrophic lateral sclerosis (ALS) but has been studied mainly in CSF. We examined pNF-H concentrations in plasma, serum and CSF as a potential biomarker for disease progression and survival in ALS.
Methodology We measured pNF-H concentration by monoclonal sandwich ELISA in plasma (n=43), serum and CSF (n=20) in ALS patients collected at the Mayo Clinic Florida and Emory University. We included plasma from an ALS cohort (n=20) from an earlier pilot study in order to evaluate baseline pNF-H levels in relation to disease progression using the Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS-R), survival and anatomical region of ALS onset.
Results Higher pNF-H levels in plasma, serum and CSF showed evidence of association with faster decline in ALSFRS-R. There was evidence for a relationship of higher serum and plasma pNF-H levels with shorter survival, although evidence was weaker for CSF. pNF-H concentration in plasma (n=62) may be higher in patients with bulbar onset than in patients with spinal onset.
Conclusions In ALS, increased pNF-H concentration in plasma, serum and CSF appears to be associated with faster disease progression. Factors affecting pNF-H levels or their detection in serum and plasma in relation to disease course may differ from those in CSF. Data raising the possibility that site of ALS onset (bulbar vs spinal) may influence pNF-H levels in peripheral blood seems noteworthy but requires confirmation. These data support further study of pNF-H in CSF, serum and plasma as a potential ALS biomarker.