Many coagulation disorders have been described in patients with AL amyloidosis (for example, factor X deficiency, factor IX deficiency, and disseminated intravascular coagulation). We report the first case of AL amyloidosis combined with acquired factor V deficiency.

In May 1990, a 33-year-old man had splenectomy after polytraumatism. The prothrombin rate was 91%. In August 1994, gastrointestinal hemorrhage occurred. The surgeon found a voluminous hematoma of the lesser peritoneal sac, but laparotomy and gastrointestinal endoscopy could not trace the origin of the bleeding. The prothrombin rate was 35%, factor V level was 25%, and antiprothrombinase antibody was present. Bleeding time, fibrinogen levels, and platelet counts were normal. Neither disseminated intravascular coagulation nor anti-factor V antibody was seen. The patient received packed red blood cells, prothrombin, and fresh frozen plasma; none of these affected prothrombin rate or factor V level. Laboratory values indicated inflammation, a pure nephrotic syndrome, and liver abnormalities with cytolysis and cholestasis. The patient did not have hypertension or renal failure. Ultrasonography showed two normal kidneys without dilatation of the urinary tract and showed hepatomegaly without thrombosis of the portal, hepatic, or renal veins. The patient was negative for serologic markers of hepatitis B and C. Prothrombin rate was 33%, and the factor V level was 17%. Antiprothrombinase antibody was detected. Bleeding time and platelet counts were normal, and no anti-factor V antibody was seen.

Liver and renal biopsies permitted diagnosis of AL amyloidosis. The patient did not have myeloma but did have a medullary infiltration with plasmocytes expressing only k light chain. Cutaneous biopsy and electromyography yielded normal results. Echo-cardiography showed alterations of left ventricular relaxation. Monthly courses of vincristine, melphalan, cyclophosphamide, and prednisone were started in December 1994. Three months later, a 54% prothrombin rate and a 60% factor V level were noted, without renal improvement. Bone marrow transplantation was done in May 1995, but the patient died in June 1995 after massive gastrointestinal hemorrhage without ulceration.

This patient had AL amyloidosis with renal, liver, medullary, and probably gastric involvement. There was no obvious myeloma, but a plasmacyte dyscrasia was seen. Factor X deficiency during amyloidosis is well known and seems to be due to an immobilization of the coagulation protein in the vasculature [1]. This explains why patients are refractory to factor X concentrates. Another study [2] showed that amyloid fibrils bind factor X and, to a much lesser extent, factor IX and prothrombin. Factor V deficiency in our patient was probably linked to amyloidosis because the patient had neither a congenital deficiency nor a deficiency due to hepatocellular deficiency, disseminated intravascular coagulation, splenomegaly, or anti-factor V antibody. Moreover, measurement of factor V levels before and after infusions of fresh frozen plasma showed that factor V levels did not increase. The mechanism of factor V deficiency may be linked to the fixation of this factor in the amyloid fibrils.