Development and Validation of Multiplex Assays for Lupus Nephritis Activity Biomarkers

Area of Science:

• Biomarker Discovery
• Immunodiagnostics
• Nephrology

Background:

• Lupus nephritis diagnosis relies on accurate biomarker measurement.
• Multiplex assays offer potential for simultaneous detection of multiple biomarkers.
• Evaluating novel multiplex assay platforms is crucial for clinical application.

Purpose of the Study:

• To develop and validate multiplex (MLP) assays for six key biomarkers of the Renal Activity Index for Lupus (RAIL).
• To compare the performance of MLP assays using Milliplex and Mesoscale Discovery (MSD) technologies against established single immunoassays.
• To establish optimal conditions for MLP assay performance in urine samples.

Main Methods:

• Development of MLP assays for adiponectin, NGAL, MCP-1, KIM-1, ceruloplasmin, and hemopexin.
• Assay validation using 104 lupus patient urine samples.
• Comparison of MLP assay results with single immunoassay gold standards on Milliplex and MSD platforms.
• Optimization of urine sample dilution for MLP assays.

Main Results:

• A 1:25 urine dilution was optimal for MLP assays.
• Milliplex MLP assays showed strong to moderate correlations with single immunoassays for KIM-1, MCP-1, NGAL, and adiponectin.
• MSD platform demonstrated weaker correlations with single immunoassays across most biomarkers.
• Ceruloplasmin and KIM-1 showed weak correlation on the MSD platform.

Conclusions:

• Milliplex MLP technology is suitable for measuring RAIL biomarker concentrations in urine samples.
• MLP assays provide a reliable method for assessing lupus nephritis activity.
• Further validation may be needed for specific biomarkers on the MSD platform.