This
is a monoclonal antibody to the A-subunit of human coagulation Factor XIII. It
recognizes human Factor XIII A-chain in both reduced and non-reduced forms. It
does not react with human Factor XIII B-chain or human Factor XII. Factor XIII
is a betaglobulin found in plasma and is composed of two subunits. Factor XIII-A
is the catalytic subunit and is a dimer of M.W. 160,000. Factor XIII is present
in plasma as an alpha2beta2 heterodimer (M.W. 320,000); whereas in platelets,
only the alpha2 unit exists. Factor XIIIa is a dermal dendrocyte marker and
shows variable reaction with these types of tumors. It can be used for
histiocytic phenotyping and has been reported to mark capillary hemangiomas and
tumors of the central nervous system. Factor XIIIa has also been used with CD34
to differentiate between dermatofibroma and dermatofibrosarcoma
protuberans.