Statistical analysis
All data were expressed as mean ± standard deviation. The intra-assay results were compared using t-tests. *P <0.05 was considered to be statistically significant difference. Five medium samples were taken for each experiment, and each experiment was repeated at least two times, using blood samples from different individuals. Data analysis was performed using Graph Prism 6.0 software (RRID:SCR_002798, La Jolla, CA, USA).