Invasive infections caused by the important pathogen Streptococcus pyogenes are often associated with disturbed blood coagulation in the human host, and may in severe cases develop into the life-threatening condition disseminated intravascular coagulation. In this study, the addition of M1 protein to human blood or purified peripheral blood mononuclear cells led to a dose-dependent increase of pro-coagulant activity, which was mediated by an upregulation of tissue factor on monocytes. Analysis of the resulting clots by transmission electron microscopy revealed that the cells were covered with a fibrin network that seemed to originate from the cell surface. Taken together, the results imply an important role for M proteins in the induction of haemostatic disorders in invasive streptococcal infectious diseases. © 2007 SGM.
Påhlman, L. I., Malmström, E., Mörgelin, M., & Herwald, H. (2007). M protein from Streptococcus pyogenes induces tissue factor expression and pro-coagulant activity in human monocytes. Microbiology, 153(8), 2458–2464. https://doi.org/10.1099/mic.0.2006/003285-0