A practical alternative to live cell-based assay for AQP4 and MOG antibody detection

Area of Science:

• Neurology
• Immunology
• Biotechnology

Background:

• Live cell-based assays (LCBA) are standard for detecting aquaporin-4 (AQP4) and myelin oligodendrocyte glycoprotein (MOG) autoantibodies in NMOSD and MOGAD.
• However, LCBA is less practical, standardizable, and cost-effective than fixed cell-based assays (FCBA).

Purpose of the Study:

• To develop and evaluate AbFine, a novel reagent to improve FCBA performance.
• To compare the diagnostic accuracy of conventional FCBA, FCBA-AbFine, and LCBA for AQP4-IgG and MOG-IgG detection.

Main Methods:

• Developed AbFine, a lysate to pre-bind and deplete interferents in patient sera before FCBA.
• Conducted a multicenter, double-blind, prospective study comparing FCBA, FCBA-AbFine, and LCBA.
• Included patients with NMOSD, MOGAD, seronegative inflammatory demyelination syndromes, and neurological disorder controls.

Main Results:

• FCBA-AbFine demonstrated higher sensitivity for AQP4-IgG (90.2%) and MOG-IgG (90.6%) compared to conventional FCBA.
• FCBA-AbFine sensitivity was comparable to LCBA for both antibodies.
• All assays achieved high specificity (>99.5%), with FCBA-AbFine showing a significantly higher area under the curve than conventional FCBA.

Conclusions:

• AbFine enables FCBA to serve as a practical and cost-efficient alternative to LCBA for AQP4-IgG and MOG-IgG detection.
• The AbFine approach can potentially be extended to other fixed cell-based assays.
• This advancement improves diagnostic capabilities for NMOSD and MOGAD.