Abstract Text: Traditional immunoassay methodologies such as ELISAs and multiplex arrays demonstrate limitations in sensitivity. These factors reduce the utility of traditional immunoassays for the detection of low-abundant plasma cytokine and chemokine levels in healthy subjects and patients, thus hampering statistical analysis among study groups. To identify the best platform for use in low abundant biomarkers, we conducted a comprehensive cross-platform and cross-assay evaluation across two leading platform technologies. The goal of this study is to evaluate the technical performance in plasma samples from kidney transplant patients with/without CMV viremia and healthy controls receiving seasonal influenza vaccination (cohort from the University of Georgia - Center for Vaccine Research for High-Risk Populations). We measured IL-2 and IL-15 using the Single molecule ultrasensitive assay (Simoa) compared to the Luminex array in plasma samples from 24 kidney transplant patients with/without CMV viremia. All 24 samples have detectable IL-2 by Simoa, 21/24 (87%) were not detectable by Luminex. 22/24 (92%) of samples have detectable IL-15 by Simoa whereas 7/22 (32%) were not detectable by Luminex. In a cohort of healthy individuals receiving a seasonal influenza vaccine, we were able to detect IL-1a in 189/212 (89%) by Simoa while it was not detected in 125/189 (66%) by Luminex. Our data suggest that ultrasensitive immune assays represent a highly accurate approach for studies that include healthy subjects or populations with a potentially heightened inflammatory state.
