Platelets are best known for their role in blood clotting, but they have a far broader toolkit. In addition to helping form scabs, they contribute to immune surveillance and even the direct destruction of pathogens.
Now, collaborating with Ludwig Oxford’s Ben Schuster-Böckler, University of Edinburgh’s Chris Gregory and Swansea University’s Paul Rees, the Psaila group have discovered another function – suppressing systemic inflammation. Platelets are scavengers, able to mop up fragments of DNA released by dead or dying cells, as well as viral RNA or DNA, clearing the accumulation of debris that could trigger inflammation or autoimmune reactions.
Cell-free (cf) DNA can also include traces of circulating tumour cell-derived DNA (ctDNA), shed by cancer cells. ctDNA is already increasingly monitored for non-invasive ‘liquid biopsies’ which detect cancers and monitor treatment responses. However, ctDNA is usually found in low levels in blood, especially during the early stages of disease, making it difficult to detect. Furthermore, current protocols isolate the cfDNA from blood plasma, once all the blood cells, including platelets, have been removed.
The study findings suggest that a substantial proportion of the cf- and ct-DNA present is contained within platelets, meaning that current tests may be missing these fragments. By adjusting the protocols used for liquid biopsies and including platelet derived DNA in the analysis, we may be able to significantly improve the early detection of cancer and the sensitivity of prenatal screening using minimally invasive methods.
To learn more about this research, read the full paper in Science: https://www.science.org/doi/10.1126/science.adp3971#sec-1