Abstract 2241: Serum and plasma IL-17A concentrations in lung cancer patients and controls

Abstract

Abstract Purpose: IL-17A, a cytokine produced by Th17 cells, is reportedly a central regulator of lung tumor growth (Reppert et al., OncoImmunology 1, 2012) and a potential serum biomarker for lung cancer (Xu et al., Biomarkers, 2014). Serum concentrations of IL-17A are too low to measure in most samples (on the order of 0.1 pg/mL) using commercially available ELISAs. In order to overcome this limitation, we developed the S-PLEX™ Human IL-17A ultrasensitive assay which is capable of accurately measuring IL-17A in serum and plasma. We used this assay to measure IL-17A concentrations in serum samples from lung cancer patients and controls. Methods: Serum samples from 59 lung cancer patients and 44 apparently healthy controls (including 14 heavy smokers) were analyzed using S-PLEX technology to determine IL-17A concentrations. In addition, IL-17A concentrations were measured in matched plasma samples from 24 of the controls. S-PLEX is a new ultrasensitive immunoassay format based on MSD's MULTI-ARRAY® electrochemiluminescence technology. The IL-17A assay requires only 25 μL of serum or plasma per measurement and can be run on the MESO® SECTOR S 600 and MESO QuickPlex® SQ 120 instruments. Results: The S-PLEX Human IL-17A assay was capable of accurately measuring IL-17A concentrations in 125 of the 127 samples tested. The lower limit of detection was 6 fg/mL and the assay range (LLOQ to ULOQ) was from 20 fg/mL to 200,000 fg/mL. Typical intra-plate coefficients of variation (CVs) ranged between 5% and 15%. Control samples run at 3 levels, in multiple replicates over multiple days, produced CVs <20%. Spike recovery and dilution linearity were between 80% and 120%, and IL-17A levels in matched serum and plasma samples were similar. Specificity of the assay was demonstrated by analyte depletion using several anti-IL-17A specific antibodies, indicating the assay is specific for the IL-17A homodimer. There was no detectable cross-reactivity to the IL-17F homodimer, and the IL-17A/F heterodimer cross-reactivity was less than 1%. In this study, IL-17A serum concentrations were not found to be significantly different between lung cancer patients and controls, with a median concentration of 183 fg/mL and interquartile range (IQR) of 88-369 fg/mL (n = 59) for lung cancer patients, compared to 128 fg/mL with an IQR of 75-198 fg/mL (n = 44) for controls. Conclusion: We have developed a highly specific and sensitive IL-17A assay that is 100 times more sensitive than the current limits of ELISA technology. This assay enables accurate determination of IL-17A concentrations in serum and plasma samples from lung cancer patients and healthy controls. The results from this study do not support the use of IL-17A as an effective serum biomarker for the presence of lung cancer. Citation Format: Animesh Shukla, Sheldon Grove, Simone Barbero, Galina N. Nikolenko, Anu Mathew, Martin K. Stengelin, Eli N. Glezer, Jacob N. Wohlstadter. Serum and plasma IL-17A concentrations in lung cancer patients and controls. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2241.