Av Gro Grimnes
Stipendiat ved TREC
When challenged with a bacterial infection, the immune system is activated, and 
through this, the body fights infection. This results in inflammation. Inflammation is closely linked to coagulation, and activated coagulation has been thought to contribute to microvascular and organ failure in severe infections.
Contrary to this, a concept called immunothrombosis has been suggested, where the formation of micro-thrombi (small blood clots) can reduce bacterial overgrowth. The different roles of coagulation during immune activation is not completely understood.
In a recent published study from Dutch researchers, mice infected with a bacteria called Klebsiella were used to study the role of thrombin in the immune response. Thrombin is an important enzyme in the coagulation cascade. Survival, spread of infection and function of parts of the immune response were compared between mice fed with a thrombin-inhibitory drug (dabigatran) and controls with normal thrombin function.
They found that mice in the treatment group had worse outcome than the control group. The infection spread to other organs earlier, their behavior was more affected, and they died earlier.
They conclude that thrombin, a central actor in coagulation, also seems to play an important role in protective immunity.
Both immune responses and coagulation are complex processes, and more research is needed in this field to get a better understanding of their interactions. There is a long way to go from laboratory studies on mice to a clinical setting with human patients. The question of whether coagulation activation during infection is a friend or foe is still not answered, and we look forward to future publications in this field!
Referanse: Claushuis TA, de Stoppelaar SF, Stroo I, et al. Thrombin contributes to protective immunity in pneumonia-derived sepsis via fibrin polymerization and platelet-neutrophil interactions. Journal of thrombosis and haemostasis (2017).
