Binding of Myeloma Monoclonal Immunoglobulin with Fibrinogen and Fibrin

Blood and plasma clots are frequently abnormal in patients with multiple myeloma a evidenced by the prolongation of clotting time, formation of bulky and gelatinous cloes and inhibition of clos retraction. It has been demonstrated in several multiple myeloma cases that the isolated immunoglobulin inhibited clot formation in normal plasma and decreased the rate of fibrin polymerization. In this work a hypothesis was tested whether these phenomena originate from binding of multiple myeloma immunoglobulin with fibrinogen and fibrin. Blood was obtained from a patient (J.I.) having IgAH gammopath; with prolonged clotting time and abnormal clot retraction. Washed plasma clots contaii ed largo amount of monoclonal IgAλ demonstrated by precipitation with anti-α or anti-λ antibodies and by the presence of heavy (65,000) and light (25,000) polypeptide chains. This myeloma IgA was incorporated into clots regardless of crosslinking and was extract able. Affinity chromatography of serum or heated plasma on insolubilized fibrin monoment resulted in recovery of large amount of myeloma monoclonal IgA, but not IgG, IgH or Igl. The isolated fibrin-specific IgA was taken up by clots obtained from normal plasma or purified fibrinogen, lnso]ubilized fibrinogen bound myeloma monoclonal IgA From plasma. Two-dimensional agarose/polyacrylamide slab gel electrophoresis demonstrated the presen of a fibrinogen-IgA complex in patient’s plasma. The results indicate that a myeloma monoclonal immunoglobulin binds with fibrinogen and fibrin, probably forming an antibot antigen complex, implying the Formation of autoantibodies against these proteins.