Disfibrinogenemia indotta da una catena leggera libera kappa delle immunoglobuline

AUTORI

ABSTRACT

Ig-free light chains induced dysfibrinogenemia

Despite several pathological conditions are associated with free light chains (FLC) deposition in human tissues, only few cases of human diseases caused by the specific binding activity of monoclonal FLC are described. A 65-year old male patient, with highly abnormal functional coagulation tests and undetectable functional fibrinogen was admitted to the Hematological Clinic of the University Hospital of Pisa. The same tests were within the reference intervals one year before. After excluding a number of causes for abnormal coagulation tests, we focused on potential causes of acquired dysfibrinogenemia. Due to the presence of abnormal values of FLC, we performed an immunofixation: while serum did not show any detectable monoclonal band, the immunofixation of a plasma sample revealed the presence of monoclonal FLC of kappa type co-migrating with fibrinogen. The serum kappa FLC concentrations were much lower than plasma levels, suggesting that the majority of these FLC were bound to fibrinogen, remaining associated to fibrin after clotting. Bone marrow biopsy showed 4% monoclonal plasma cells producing kappa light chains. The patient was diagnosed as affected by a FLC MGUS. After two courses of dexamethasone, the plasma concentration of kappa FLC decreased substantially and most of the coagulation tests normalized. The nature of the interaction between fibrinogen and kappa FLC is currently under investigation to elucidate the mechanism able to inhibit fibrinogen polymerization.

BIBLIOGRAFIA