ABSTRACT
This chapter investigates human peripheral blood cells in smears for FXIII content using immunomorphological methods. FXIIIa is a transglutaminase that cross-links fibrin by catalyzing the formation of ϵ(γ-glutamyl)lysyl isopeptide bonds. There are pieces of evidence suggesting that the physiopathologic importance of FXIII is not limited exclusively to blood coagulation. It has an essential role in the process of wound healing by stimulating proliferation. Monocytes stained for FXIII subunit a showed a highly intensive reaction of cytoplasmic localization, which was completely abolished by the preabsorption of the antiserum with highly purified human FXIII. In normal lymph nodes FXIII-containing cells occurred almost exclusively in the connective tissue of capsule and in the sinus. On the role of FXIII present in this cell population only speculation can be provided. FXIII activity secreted or released from destroyed macrophages into the surroundings is by all means involved in cross-linking of fibrin in the tumor stroma.
