DNA methylation is an epigenetic mechanism that ensures specific gene expression in different cell types.
In 2007, scientists at Epiontis GmbH (Berlin, Germany) identified genomic regions that are specifically de-methylated (i.e. no DNA methylation) in FOXP3+ regulatory T cells (Treg)1).
Regulatory T cells play important roles in fine-tuning the immune system to keep a balance between defending "foreign" and tolerating "own" cells in the body.
Epiontis scientists then developed quantitative real-time PCR (qPCR) assays to enumerate Treg cells by extracting DNA from human samples and subjecting the isolated DNA to epigenetic qPCR2).
Enumeration of Treg (and other immune cells) is important for clinicians to determine the immune status of patients with e.g. autoimmune diseases or inherited disorders of the immune system3).
Different to the current standard in clinical practice, epigenetic immune cell quantification does not require a fresh blood draw but only a drop of blood that can be dried on a filter paper or frozen and sent to a central laboratory for analysis.
Meanwhile, more than 20 immune cell type-specific epigenetic qPCR assays were established and successfully applied in more than 100 clinical studies with pharmaceutical companies.
It was successfully shown that the results obtained by epigenetic qPCR are equivalent to the results generated by flow cytometry - the current standard for enumeration of immune cells in human samples4).
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