Comparison of Methods of Detecting IL-1β in the Blood of Alzheimer's Disease Subjects.

Interleukin (IL)-1β is a pro-inflammatory cytokine whose levels are increased in the brains of Alzheimer's disease (AD) patients. Despite the role of IL-1β in the pathology of AD, the fact that it is expressed at very low levels makes it a challenging cytokine to measure, hence limiting its potential use as a reliable biomarker. Moreover, being able to accurately and reliably measure the levels of IL-1 β in blood makes it possible to evaluate this cytokine as a potential biomarker of the inflammatory response in AD. In this study, we compared three quantification methodologies, Meso-Scale Discovery (MSD), both V-Plex and S-Plex versions, and Quanterix's SIMOA (Single-Molecule Array), to measure IL-1β in the serum of AD patients and age-matched controls. These assays are routinely used to measure IL-1β serum levels with high specificity and sensitivity in human AD patients, yet to the best of our knowledge, no study has compared all three techniques for their accuracy to measure IL-1β as biomarkers. Our findings indicate the two MSD assays can be used to measure IL-1β levels in AD and control serum, but the SIMOA assay showed the highest receiver operating characteristics (ROCs), with an area under the curve (AUC) of 0.9532, which can be compared to the AUC values for the V-Plex assay, 0.5660, and the S-Plex assay, 0.6632. Taken together, these data show that although all technologies are useful in the measurement of IL-1β in the blood, the SIMOA IL-1β 3.0 assay is more reliable and sensitive in measuring biomarkers of AD.