The possible role of fibronectin in multiple myeloma

Fibronectin (FN) has an active role in the immune response, interacting with a number of different cells and components. It has been implicated in the formation of cryoprecipitates in rheumatic diseases and is present in tissues where under pathological conditions immune complexes are deposited. Under physiological conditions of pH and ionic strength both heavy and light chain of all multiple myeloma and normal IgG show affinity to FN. FN binds to both B and T cells and is shown to inhibit thrombin and collagen-induced platelet aggregation. We have found elevated levels of FN in the plasma of multiple myeloma patients tested compared to a group of normal subjects. Even though the level of FN did not correlate with the level of the paraprotein, our findings raise the possibility that FN might be implicated in some of the clinical symptoms of multiple myeloma.