Journal of Bioanalysis & Biomedicine

Estimation of the True Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) Autoantibody Concentration in the Sera of Normal Subjects

Abstract

Keiko Shiiya, Mariko Iizuka, Yuko Ito, Seino Utako, Hashimoto Atsushi, Takahiro Tanaka, Keiichi Akasaka, Nobutaka Kitamura, Yoshikazu Inoue, Ryushi Tazawa and Koh Nakata*

According to our previous studies, Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) autoantibodies (GMAbs) are normally present in healthy people. To date, antigen-antibody capture assay has measured the concentrations. However, nonspecific IgG other than GMAbs and immune complex formation with intrinsic GM-CSF prevents us from measuring the accurate concentrations. To solve these problems, we developed a liquid phase high-sensitivity assay using biotinylated GM-CSF (bGM-CSF) and streptavidin coated plate, which could measure the concentration of GMAbs over 0.02 ng/ml. Using this method, the true GMAbs concentration in 30 normal subjects was estimated to be 52.6 ng/ml for the median value, ranging 10.6 to 799.5 ng/ml. Thus, we propose a novel method that enables us to estimate the true concentration of GMAbs in the sera of healthy subjects.