A Serum Biomarker Panel and Miniarray Detection System for Tracking Disease Activity and Flare Risk in Lupus Nephritis

Chenling Tang¹Gongjun Tan¹Aygun Teymur¹Jiechang Guo¹Arturo Haces-Garcia¹Weihang Zhu¹Richard Williams²Jing Ning³Ramesh Saxena⁴Tianfu Wu^1*

• ¹University of Houston, Houston, United States
• ²Iolight Co, Hampshire, United Kingdom
• ³Department of Biostatistics, University of Texas MD Anderson Cancer Center, Houston, Texas, United States
• ⁴University of Texas Southwestern Medical Center, Dallas, Texas, United States

By integrating serum immunoassay screening with genomic expression databases and machine learning techniques, we discovered a biomarker panel of lupus nephritis (LN) to develop a sandwich-structure quantitative immunoarray. The sensitivity, specificity, reproducibility, and stability of the biomarker-panel mini-array (BPMA) were examined. Serum samples from LN patients and healthy controls were tested to compare the performance of BPMA with ELISA. The performance of BPMA in disease monitoring was validated with machine models using a larger cohort of LN. The BPMA was also used to determine LN flare using a machine-learning generated flare score (F-Score).Among 32 promising LN serum biomarkers, VSIG4, TNFRSF1b, VCAM1, ALCAM, OPN, and IgG anti-dsDNA antibody were selected to constitute an LN biomarker Panel, which exhibited excellent discriminative value in distinguishing LN from healthy controls (AUC = 1.0) and active LN from inactive LN (AUC = 0.92), respectively. Also, the 6-biomarker panel exhibited a strong correlation with key clinical parameters of LN. A multiplexed immunoarray was constructed with the 6-biomarker panel (named BPMA-S6 thereafter). An LN-specific 8-point standard curve was generated for each protein biomarker. Cross-reaction between these biomarkers was minimal (< 1%). BPMA-S6 test results were highly correlated with those from ELISA (Spearman's correlation: fluorescent detection, rs = 0.95; colorimetric detection, rs = 0.91). The discriminative value of BPMA-S6 for LN was further validated using an independent cohort (AUC = 0.94). Using a longitudinal cohort of LN, the derived F-Score exhibited superior discriminative value in the training dataset (AUC = 0.92) and testing dataset (AUC=0.82) to distinguish flare vs remission.BPMA-S6 may represent a promising point-of-care test (POCT) for the diagnosis, disease monitoring, and assessment of LN flare.