Local activation of coagulation factor XIII reduces systemic complications and improves the survival of mice after Streptococcus pyogenes M1 skin infection.

Coagulation is a mechanism for wound healing after injury. Several recent studies delineate an additional role of the intrinsic pathway of coagulation, also known as the contact system, in the early innate immune response against bacterial infections. In this study, we investigated the role of factor XIII (FXIII), which is activated upon coagulation induction, during Streptococcus pyogenes-mediated skin and soft tissue infections. FXIII has previously been shown to be responsible for the immobilization of bacteria within a fibrin network which may prevent systemic bacterial dissemination. In order to investigate if the FXIII-mediated entrapment of S. pyogenes also influences the disease outcome we used a murine S. pyogenes M1 skin and soft tissue infection model. Here, we demonstrate that a lack of FXIII leads to prolonged clotting times, increased signs of inflammation, and elevated bacterial dissemination. Moreover, FXIII-deficient mice show an impaired survival when compared with wildtype animals. Additionally, local reconstitution of FXIII-deficient mice with a human FXIII-concentrate (FibrogamminP) could reduce the systemic complications, suggesting a protective role for FXIII during early S. pyogenes skin infection. FXIII therefore might be a possible therapeutically application to support the early innate immune response during skin infections caused by S. pyogenes.