Abstract Details

Title Evaluation of a Point-of-Care Diagnostic Test for Aquaporin-4 Seropositive Neuromyelitis Optica Spectrum Disorder

Topic Autoimmune Neurology

Presentation(s) S3 - Autoimmune Neurology 1: Mechanisms of Disease, Clinical Practice (2:24 PM-2:36 PM)

Poster/Presentation
Number 008

Background Given the need for sophisticated techniques and specialized laboratories, diagnostic testing for AQP4 is not globally accessible.

Objective To evaluate a novel point-of-care, filter paper-based test for serum antibodies to aquaporin-4 (AQP4), a protein associated with neuromyelitis optica spectrum disorder (NMOSD).

Design/Methods Adults with diagnosed AQP4 seropositive NMOSD were recruited at the Massachusetts General Hospital. Controls were adults with a diagnosis of a different CNS demyelinating disease and documented AQP4 Ab seronegativity. Participants used 1.5mm lancets to draw blood from their index fingers and placed approximately 1mL on Whatman® 903 Protein Saver Cards (in-person or remotely). A 12.5mm circle of each sample was soaked in 200 microL PBS, added to transfected AQP4-GFP HEK293 cells at a 1:9 ratio, and incubated. Cells were washed, fixed, and blocked with 10% goat serum and incubated again. Vectorshield with DAPI was added for visualization. Samples were analyzed by blinded laboratory staff. Results were compared to participants’ clinical AQP4 Ab test results. The primary outcomes were sensitivity, specificity, and positive and negative predictive value.

Results Of 40 participants (mean age 53.7 years; 83% female; 75% White, 10% Black, 8% Asian; 13% Hispanic/Latinx), 25 were cases and 15 were controls. The most common diagnosis of controls was multiple sclerosis (73%). The average NMOSD disease duration was 6.3 years. All seropositive participants were on disease modifying therapies at the time of participation, including rituximab (72%), eculizumab (8%), inebilizumab (8%), mycophenolate mofetil (8%), and ravulizumab (4%). The point-of-care test yielded a sensitivity of 80% and a specificity of 93%. The positive predictive value was 95%, and the negative predictive value was 74%.

Conclusions

The point-of-care AQP4 test demonstrated excellent specificity and sensitivity. This method may reflect a pragmatic option for expanding diagnosis of NMOSD in settings where AQP4 antibody testing is not accessible.

Authors/Disclosures
Dylan R. Rice PRESENTER	Mr. Rice has nothing to disclose.
Shuhei Nishiyama, MD, PhD (Tohoku University Graduate school of Medicine)	Dr. Nishiyama has nothing to disclose.
	No disclosure on file
Ana Maria M. Cabal Herrera, MD (Nationwide Children's Hospital)	Ms. Cabal Herrera has nothing to disclose.
Michael Levy, MD, PhD, FAAN (Massachusetts General Hospital/Harvard Medical School)	Dr. Levy has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Mitsubishi Pharma. Dr. Levy has received personal compensation in the range of $500-$4,999 for serving as a Consultant for UCB Pharma. Dr. Levy has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for Sanofi. Dr. Levy has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Alexion. Dr. Levy has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Horizon. Dr. Levy has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Genentech. Dr. Levy has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Elsevier. Dr. Levy has received personal compensation in the range of $10,000-$49,999 for serving as an Expert Witness for Various law firms. The institution of Dr. Levy has received research support from National Institutes Health.
Farrah J. Mateen, MD, PhD, FAAN (Massachusetts General Hospital)	Dr. Mateen has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Horizon Therapeutics. Dr. Mateen has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Genentech. Dr. Mateen has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for EMD Serono. Dr. Mateen has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Alexion. Dr. Mateen has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Neurology. The institution of Dr. Mateen has received research support from Genentech. The institution of Dr. Mateen has received research support from EMD Serono. The institution of Dr. Mateen has received research support from Novartis. The institution of Dr. Mateen has received research support from Horizon Therapeutics.