GlycoTyper-a novel liquid-biopsy platform for high-throughput, high-sensitivity targeted glycoproteomics, exemplified by differentiating Systemic Lupus Erythematosus and Lupus Nephritis

Importance of the Topic

Systemic lupus erythematosus (SLE) is a complex autoimmune disease that frequently leads to lupus nephritis (LN), a severe kidney complication. Early detection and monitoring of LN are critical to prevent irreversible renal damage and progression to end-stage renal disease. Currently, diagnosis relies on invasive renal biopsies, highlighting the need for noninvasive, high-throughput liquid biopsy approaches.

Objectives and Study Overview

This study introduces GlycoTyper, a novel liquid-biopsy platform designed to profile N-glycans from affinity-captured target proteins in patient biofluids. The primary goal was to differentiate LN patients from those with SLE without nephritis and healthy controls (HC) and to evaluate glycan signatures associated with response to immunosuppressant therapy over time.

Methodology

• Affinity Capture: IgG antibodies in patient plasma were captured on antibody arrays printed on Nexterion-H-coated glass slides adapted to a multi-well format.
• Glycan Release: Captured IgG N-glycans were enzymatically cleaved using PNGase F.
• Matrix Application and MS Readout: Slides were coated with matrix and analyzed by MALDI mass spectrometry.
• Quality Control: System suitability tests and QC arrays were interspersed to ensure reproducibility and data integrity.
• Data Analysis: A random forest classifier was trained to distinguish LN, SLE, and HC based on glycan feature abundances.

Used Instrumentation

• Bruker timsTOF fleX MALDI mass spectrometer
• Nexterion-H-coated glass slides for glycan array format
• PNGase F enzyme for N-glycan release

Main Results and Discussion

• The random forest model achieved an AUC of 0.87, sensitivity of 0.90, and specificity of 0.88 in distinguishing LN from SLE/HC at baseline.
• Two specific sialylated, afucosylated biantennary N-glycans were among the top predictive features for LN classification and correlated with treatment outcomes.
• Patients with higher baseline levels or increasing trends of these glycans under immunosuppressant therapy exhibited worse renal outcomes as measured by urine protein-to-creatinine ratio (UPCR).

Benefits and Practical Applications

The GlycoTyper platform offers a noninvasive, high-sensitivity method for early LN detection and stratification. Glycan profiling may serve as an independent biomarker source, informing personalized treatment decisions and enabling longitudinal monitoring of therapy response.

Future Trends and Opportunities

Advancements may include multiplexed capture of diverse protein targets, integration with automated sample preparation, expansion to other autoimmune or oncological indications, and adoption of machine-learning models for enhanced diagnostic accuracy.

Conclusion

This work demonstrates that targeted glycoproteomic analysis via the GlycoTyper platform can reliably differentiate LN from SLE and healthy states while providing prognostic insights into immunosuppressant therapy outcomes. The approach holds promise for translation into routine clinical workflows as a minimally invasive diagnostic and monitoring tool.

References

• Huffman G., Grimsley G., Angerstein A., Nowling T., Drake R., Castellino S., Lindpaintner K. GlycoTyper – a novel liquid-biopsy platform for high-throughput, high-sensitivity targeted glycoproteomics, ASMS 2025, TP 082.