The cell-free DNA (cfDNA) is always present in plasma, and it is biomarker of growing interest in prenatal diagnostics as well as in oncology and transplantology for therapy efficiency monitoring. But does this cfDNA have a physiological role? Here we show that cfDNA presence and clearance in plasma of healthy individuals plays an indispensable role in immune system regulation. We exposed THP1 cells to healthy individuals' plasma with (NP) and without (TP) cfDNA. In cells treated with NP, we found elevated expression of genes whose products maintain immune system homeostasis. Exposure of cells to TP triggered an innate immune response (IIR), documented particularly by elevated expression of pro-inflammatory interleukin 8. The results of mass spectrometry showed a higher abundance of proteins associated with IIR activation due to the regulation of complement cascade in cells cultivated with TP. These expression profiles provide evidence that the presence of cfDNA and its clearance in plasma of healthy individuals regulate fundamental mechanisms of the inflammation process and tissue homeostasis. The detailed understanding how neutrophil extracellular traps and their naturally occurring degradation products affect the performance of immune system is of crucial interest for future medical applications.

• MeSH
• Biomarkers blood   MeSH
• Chromatography, Liquid MeSH
• Adult MeSH
• Extracellular Traps immunology   MeSH
• Mass Spectrometry MeSH
• Plasma MeSH
• Middle Aged MeSH
• Humans MeSH
• Young Adult MeSH
• Monocytes immunology   MeSH
• Immunity, Innate * MeSH
• Oligonucleotide Array Sequence Analysis MeSH
• Tandem Mass Spectrometry MeSH
• THP-1 Cells MeSH
• Cell-Free Nucleic Acids blood   MeSH
• Inflammation MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Young Adult MeSH
• Male MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Biomarkers MeSH
• Cell-Free Nucleic Acids MeSH