A Complete-Panel Islet Autoantibody Multiplex ECL Assay

Background: Type 1 diabetes (T1D), a major chronic autoimmune disease starting mostly from childhood, is now predictable with the measurement of four major islet autoantibodies (IAbs) including IAA, GADA, IA-2A and ZnT8A. Currently, there are approximately 1.4 million people affected with T1D in the United States and the incidence has doubled in the last 20 years, especially in young children. Mass screening for eligible subjects and the general population remains inefficiency and laborious bottleneck. Methods: With the platform of our extensively validated high affinity electrochemiluminescence (ECL) assay, we have developed a simple multiplexed ECL assay to combine all four major IAb assays in a single well. Two cohorts were studied including 80 samples from newly diagnosed patients with T1D and 1,140 from Autoimmunity Screening for Kids (ASK) study. Both multiplex ECL assay and standard radio-binding assay (RBA) were performed in parallel. Results: With >99th percentile of specificity for both assays in over 1,000 samples from general population, sensitivity of multiplex ECL assay in new onset patients with T1D were similar to RBA, GADA 75% vs. 71%; IA-2A 91% vs. 90%; IAA 61% vs. 65%; ZnT8A 90% vs. 87%. In ASK cohort, multiplex ECL assay was concordant with RBA among children with multiple IAbs (42/44, 96%). In contrast, only 39% (21/54, p<0.0001) of children with single IAb by RBA were positive by multiplex ECL assay. Conclusion: Multiplex ECL assay illustrated its high sensitivity/specificity as RBA in T1D patients. In general population screening, multiplex ECL assay, similar to single ECL assay, is capable to discriminate high risk IAbs from low risk IAbs generated by RBA. With a multiplexing feature, it provides a high throughput tool with low cost and low sample volume for large scale of population screening for T1D. Disclosure L. He: None. X. Jia: None. D. Miao: None. C. Geno rasmussen: None. M. Rewers: Advisory Panel; Self; Provention Bio, Inc., Consultant; Self; RTI, Research Support; Self; Janssen Research & Development, LLC, JDRF. L. Yu: None. Funding JDRF (2-SRA-2018-533-S-B, 1-SRA-2016-208-S-B); National Institutes of Health (DK32083); Diabetes Research Center (P30DK116073)