Abstract Details

Title Relationship of Transcobalamin Receptor Antibodies with Baseline Features and Clinical Progression in Parkinson’s Disease

Topic Movement Disorders

Presentation(s) P6 - Poster Session 6 (5:00 PM-6:00 PM)

Poster/Presentation
Number 16-008

Objective To measure the prevalence of serum transcobalamin receptor antibodies (CD320ab) in a large cohort of patients with early Parkinson’s disease (PD) and to assess their relationship with baseline characteristics and clinical progression.

Background The transcobalamin receptor (CD320) mediates the entry of holoTC, transporting vitamin B12 (B12) into the central nervous system (CNS). CD320ab have recently been identified which block CNS uptake of holoTC and are associated with “Autoimmune B12 Central Deficiency,” a condition in which neurological symptoms related to B12 deficiency occur despite normal serum B12. Since low B12 levels have been shown to be associated with severity and rate of progression of PD, we sought to determine whether CD320ab are common in PD, and whether they were associated with baseline features or clinical progression.

Design/Methods Measurements of baseline CSF and serum B12 and holoTC were available from participants with early untreated PD from the DATATOP study. Serum samples were tested using a Luminex assay to detect CD320ab. Samples were considered seropositive for the CD320 antigen (CD320ab+) using a fold change cutoff of 100. An unpublished study for this assay in a control population without PD showed a prevalence rate of 9.4%.

Results The prevalence rate of CD320ab+ was 12.7% (72/566). The mean (SD) CSF holoTC/serum holoTC ratio in males was lower in CD320ab+ than in CD320ab- (0.23 (0.07) vs 0.25 (0.02), p=0.03), but not in females. Baseline clinical features did not differ between CD320ab+ and CD320ab- participants. Mean annualized change in UPDRS and MMSE did not differ between these groups.

Conclusions We found a numerically higher prevalence of CD320ab+ in this cohort than in a control population. Baseline features and annualized rates of progression did not differ according to CD320ab status. Further studies are needed to determine whether CD320ab are associated with an elevated risk for PD.

Authors/Disclosures
Chadwick W. Christine, MD, FAAN PRESENTER	The institution of Dr. Christine has received research support from Michael J Fox Foundation for Parkinson's Research. The institution of Dr. Christine has received research support from Aspen Neurosciences. The institution of Dr. Christine has received research support from ASK BIo. The institution of Dr. Christine has received research support from Bayer.
John Pluvinage, MD, PhD (UCSF)	The institution of Dr. Pluvinage has received research support from NINDS.
Peggy Auinger (University of Rochester)	Ms. Auinger has nothing to disclose.
Esther Rodriguez-Forti	Esther Rodriguez-Forti has nothing to disclose.
Lyvin Tat (ÚC Davis Medical Center)	Lyvin Tat has nothing to disclose.
Ralph Green (UCDavis)	Dr. Green has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for WiiTi. Dr. Green has received personal compensation in the range of $5,000-$9,999 for serving on a Speakers Bureau for Abbott.
Michael R. Wilson, MD, FAAN (University of California San Francisco)	Dr. Wilson has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Pfizer. Dr. Wilson has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Ouro Medicines. Dr. Wilson has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Vertex Pharmaceuticals. Dr. Wilson has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Indapta Therapeutics. Dr. Wilson has received personal compensation in the range of $50,000-$99,999 for serving as an officer or member of the Board of Directors for Delve Bio. Dr. Wilson has received personal compensation in the range of $500-$4,999 for serving as an Expert Witness for Cambridge Medical Experts. Dr. Wilson has received personal compensation in the range of $5,000-$9,999 for serving as an Expert Witness for Dunham Hallmark. Dr. Wilson has stock in Delve Bio. The institution of Dr. Wilson has received research support from Genentech / Roche. The institution of Dr. Wilson has received research support from NIH. The institution of Dr. Wilson has received research support from Novartis. The institution of Dr. Wilson has received research support from National Multiple Sclerosis Society. The institution of Dr. Wilson has received research support from Fanconi Anemia Research Foundation. The institution of Dr. Wilson has received research support from Department of Defense. The institution of Dr. Wilson has received research support from Chan Zuckerberg Initiative. The institution of Dr. Wilson has received research support from Kyverna Therapeutics. Dr. Wilson has received intellectual property interests from a discovery or technology relating to health care. Dr. Wilson has received intellectual property interests from a discovery or technology relating to health care. Dr. Wilson has received personal compensation in the range of $10,000-$49,999 for serving as a Expert Witness with US Dept of Justice.

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