Immunoglobulin Light Chain Amyloidosis with Severe Liver Dysfunction Accompanied by Factor X Deficiency

Severe hepatic failure is rarely a cause of death in patients with immunoglobulin light chain (AL) amyloidosis. We herein report a case of AL amyloidosis involving a bleeding tendency due to factor X deficiency and marked hepatic involvement of amyloidosis. The patient died due to severe liver dysfunction two weeks after admission. The diagnosis was confirmed histologically by AL-λ amyloidosis, with the liver and spleen as the main lesions, on an autopsy. As treatment-related toxicity is strong in advanced cases, appropriate treatments are required to improve the prognosis of AL amyloidosis with severe liver dysfunction.

Factor X Deficiency Caused by Nonsecretory Myeloma Successfully Corrected with Bortezomib: A Case Report and Review of the Literature

A 62-year-old female presenting with anemia and extensive hemorrhages is reported. Coagulation tests showed significantly prolonged prothrombin time (PT) and activated partial thromboplastin time. Decreased levels of clotting factor X activity were determined (5.4%). Bone marrow biopsy revealed neoplastic plasma cells. Serum and urine protein electrophoresis were both negative for monoclonal gammopathy, and both bone marrow and abdominal fat biopsies were negative for amyloid deposition. The patient was diagnosed as suffering from nonsecretory multiple myeloma (MM) complicated by acquired factor X deficiency. A complete response (CR) of the myeloma and recovery of factor X activity (56.6%) were achieved after the administration of treatment, including chemotherapy and bortezomib. We suggest that patients with nonsecretory MM might present with factor X deficiency and should be carefully screened for light chain amyloidosis. Novel agents such as bortezomib should be highly considered as treatment in these patients.

A case of factor X deficiency in a Chihuahua dog

A juvenile Chihuahua dog developed hemoperitoneum after routine ovariohysterectomy. She was managed with packed red blood cell and fresh frozen plasma transfusions as well as an exploratory laparotomy to verify ligature sites. No recurrence of hemorrhage occurred. Factor X deficiency was diagnosed and confirmed with repeat analysis including during times of health.

[Isolated factor X deficiency in chronic myelomonocytic leukemia: Report of one case]

Bleeding disorders are commonly associated with hemato-oncologic diseases. We report a 68 years old male with a chronic myelomonocytic leukemia derived from a long lasting mielodysplastic syndrome that did not respond to treatment with Azacitidine. The patient was hospitalized due to tonic clonic seizures. A CAT scan showed a hematoma in the frontal lobe. A new assessment of hemostasis revealed an isolated deficiency of Factor X. We speculate that this deficit could be secondary to consumption due to the chronic Myelomonocytic Leukemia.

[Acquired factor X deficiency developed four years after autologous transplantation in a patient with multiple myeloma associated with systemic AL amyloidosis]

We describe a case of acquired factor X deficiency after high-dose melphalan with autologous stem cell transplantation (HDM/ASCT) for multiple myeloma (MM) with systemic AL amyloidosis. A 68-year-old woman with renal amyloidosis was diagnosed as having MM in 2007. She achieved a partial response after VAD (vincristine, adriamycin, dexamethasone) therapy and HDM/ASCT. In December 2011, coagulation tests revealed a prolonged prothrombin time (PT) of 17.6 sec and she was administered vitamin K. In January 2012, she received low anterior resection with colostomy for rectal cancer. She received fresh frozen plasma (FFP) infusion but the perioperative bleeding tendency persisted. In February 2012, she was referred from surgery for colostomy closure. She showed no progression of MM and had prolonged PT, corrected by mixing with normal plasma. Factor X activity was markedly decreased. She was diagnosed as having an acquired factor X deficiency and was given FFP infusion for colostomy closure. Although acquired factor X deficiency after HDM/ASCT for MM with systemic AL amyloidosis is rare, we should be aware of the possibility of this disease in MM patients with a bleeding tendency.

Acquired factor X deficiency associated with atypical AL-amyloidosis

We herein describe the case of a 77-year-old woman with acquired factor X deficiency that was likely caused by atypical amyloidosis. The patient developed severe gastrointestinal bleeding as a result of a significant decrease of factor X activity. Neither proteinuria nor diarrhea was observed as an initial manifestation. Although a bone marrow examination revealed direct fast scarlet-positive extracellular deposits, they did not exhibit red-to-green dichroism under polarized light. Immunofluorescence microscopy showed that the fibrillar proteins were positive for CD138 but negative for β2-microglobulin or amyloid A antibodies. These atypical pathological features of immunoglobulin light chain-amyloidosis in this patient might be related to its unique clinical presentation.

[AL amyloidosis-associated factor X deficiency]

BACKGROUND

An acquired bleeding tendency is a specific symptom that can indicate an underlying disease.

CASE DESCRIPTION

Here we describe a 69-year-old patient with an acquired bleeding tendency resulting from a factor X deficiency due to an underlying amyloid light-chain (AL) amyloidosis. Factor X deficiency in AL amyloidosis arises from a quantitative and qualitative deficiency of factor X because it binds to amyloid fibrils exposed to circulating blood.

CONCLUSION

Bleeding tendency is a rare complication of AL amyloidosis, often resulting from a factor X deficiency.

Acquired-transient factor X deficiency in a teenager with extensive burns

Acquired factor X deficiency is an extremely rare situation. It has shown to be associated with systemic amyloidosis, respiratory mycoplasma infection, factor X inhibitors, antiphospholipid antibodies, vitamin K deficiency/liver disease as well as the use of certain medications (meropenem, valproic acid). The pathogenesis and transient nature of this deficit remain poorly understood. The authors describe the case of a teenager hospitalised for extensive burns that developed active bleeding after removal of central venous catheter. He was diagnosed with transient factor X deficiency. Normalisation of coagulation status and factor X levels occurred spontaneously 10 days after the bleeding episode.

Systemic AL amyloidosis with acquired factor X deficiency: A study of perioperative bleeding risk and treatment outcomes in 60 patients

Systemic light-chain (AL) amyloidosis may be associated with acquired factor X (FX) deficiency and optimal management of this coagulopathy is unknown. We reviewed our experience with 60 patients with isolated FX deficiency (< or =50%) due to AL amyloidosis that underwent an invasive procedure between 1975 and 2007. They were classified as having severe (<10%; n = 6), moderate (10-25%; n = 15), or mild (26-50%; n = 39) FX deficiency. The patients underwent a total of 112 procedures, 19 (17%) of which were managed with periprocedural treatment with one or more hemostatic agents. There were complications in 14 (13%) procedures (bleeding = 12, thrombosis = 1, death = 1). Baseline FX level was not predictive of bleeding risk; the only association with postintervention bleeding was central venous catheter placement. However, bleeding complications were relatively infrequent, particularly in patients with mild or moderate FX deficiency undergoing nonvascular procedures. Activated recombinant factor VII might be considered in patients undergoing major surgical procedures, but further experience is needed. Optimal management of AL patients with FX deficiency undergoing invasive procedures remains to be determined.

Treatment of acquired factor X inhibitor by plasma exchange with concomitant intravenous immunoglobulin and corticosteroids

A patient with spontaneous hemorrhage from multiple body sites was found to have markedly prolonged international normalized ratio (INR) and activated partial thromboplastin times (aPTT) with incomplete correction of aPTT on mixing studies using normal plasma. The cause of this severe hemorrhage was due to a specific factor X inhibitor. No underlying or associated diseases were found. Initial treatment with fresh frozen plasma, vitamin K, and recombinant activated factor VII (rFVIIa) was unsuccessful. However, therapy utilizing plasma exchange with concomitant intravenous immunoglobulin and corticosteroids resulted in a rapid and sustained normalization of factor X levels with a clinical hemostatic response.

Refractory hematuria from amyloidosis successfully treated by splenectomy

Systemic amyloidosis can result in a coagulopathy that is associated with low levels of factor X. We present a case of intractable, life-threatening hematuria that was successfully managed with activated recombinant human factor VII and splenectomy.

Spontaneous major bleeding in acquired factor X deficiency secondary to AL-amyloidosis

Abnormal bleeding may be seen in up to a third of patients with amyloidosis. Factor X deficiency is the commonest acquired coagulopathy in amyloidosis. While mild intracutaneous bleeding is common, spontaneous life-threatening haemorrhage is rare. We report a case of acquired FX deficiency due to amyloid light chain (AL)-amyloidosis presenting with spontaneous retroperitoneal bleeding. The diagnostic and management issues in this patient are discussed.

Four factor deficiency

Four factor deficiency is variably associated with mild to fatal bleeding. We describe a 3-month-old boy, born of consanguineous parents, who presented with a right subdural haematoma and a clotting screen showing a prothrombin time (PT) > 100 s, an activated partial thromboplastin time (aPTT) > 150 s, a fibrinogen of 0.4 g/l, and fibrinogen degradation products < 1 microg/ml. He was given 300 U of factor IX concentrate (containing factors II and X) and 1 mg of vitamin K intravenously. Forty-five minutes later, clotting tests showed a PT of 24 s, an aPTT of 31 s and a fibrinogen of 2.6 g/l. The patient was found to be deficient in all the vitamin K-dependent factors: factors II, VII, IX and X, protein C and protein S. A 14-base deletion was found in intron 1 (bases 1056-1069) of the gamma-carboxylase gene. The patient and his elder sister were homozygous for this deletion, whereas both parents were heterozygous. The deletion destroys a reverse palindromic sequence (TTGAGGCAA) of the type often associated with cis-acting elements. Our results suggest that this element may be involved in the regulation of gamma-carboxylase expression. Expression studies are being completed so that this region can be definitively ascribed as a cis-acting element involved in gene regulation.

Successful perioperative management of factor X deficiency associated with primary amyloidosis

Acquired bleeding abnormalities are common in patients with primary amyloid light-chain amyloidosis. Factor X deficiency is the most common coagulopathy associated with life-threatening hemorrhagic complications when surgery is indicated. Fresh-frozen plasma (FFP) or prothrombin complex concentrates (PCCs) are the most frequently used blood products in this disease; however, FFP is often ineffective in controlling bleeding and PCCs have a significant risk of thrombosis when used intraoperatively. This report describes a patient with primary amyloidosis and factor X deficiency who underwent hemicolectomy with preoperative and intraoperative administration of recombinant human factor VIIa and postoperative administration of Bebulin (a PCC that contains the highest concentration of factor X). The management was successful with no signs of bleeding postoperatively. To our knowledge, few reports of successful perioperative management of factor X deficiency have been published to date. This is the first case report using recombinant human factor VIIa and Bebulin in the perioperative management of factor X deficiency associated with primary amyloidosis. Recombinant human factor VIIa and Bebulin may allow for successful perioperative management of bleeding disorders in patients with primary amyloidosis.

Successful treatment of systemic amyloidosis with hepatic involvement and factor X deficiency by high dose melphalan chemotherapy and autologous stem cell reinfusion

Systemic amyloidosis with hepatic involvement is a rare disorder, which is characterized by the deposits of amyloid fibrils in the liver. The prognosis is poor and the median survival is 13 months. Bleeding problems resulting from coagulopathy frequently complicates systemic amyloidosis. We present two patients with a severe factor X deficiency and hepatomegaly as the presenting abnormalities of systemic amyloidosis. One of the patients was treated with high dose melphalan chemotherapy and autologous stem cell reinfusion, resulting in a normalization of the liver enzyme tests and the factor X level. The diagnosis and treatment of systemic amyloidosis with hepatic involvement and the management of the multifactorial coagulopathy in these cases is discussed.

Lupus anticoagulant associated with transient severe factor X deficiency: a report of two patients presenting with major bleeding complications

Acquired factor X (FX) deficiency is rare, but has been reported in diverse disease states, including systemic amyloidosis and respiratory infections. FX deficiency associated with lupus anticoagulant (LA) and a bleeding diathesis has not been previously reported. We report two patients both of whom presented with a severe bleeding diathesis after a preceding respiratory infection due to isolated FX deficiency associated with a LA. The FX deficiency and LA were transient. We conclude that patients with LA may rarely present with severe acquired FX deficiency. This may be another mechanism whereby patients with antiphospholipid antibodies present with bleeding complications.

Acquired factor X deficiency in patients with amyloid light-chain amyloidosis: incidence, bleeding manifestations, and response to high-dose chemotherapy

Acquired deficiency of factor X occurs in patients with systemic amyloid light-chain (AL) amyloidosis, presumably due to adsorption of factor X to amyloid fibrils. Of 368 consecutive patients with systemic AL amyloidosis evaluated at Boston Medical Center, 32 patients (8.7%) had factor X levels below 50% of normal. Eighteen of these patients (56%) had bleeding complications, which were more frequent and severe in the 12 patients below 25% of normal; 2 episodes were fatal. Ten factor X-deficient patients received high-dose melphalan chemotherapy followed by autologous stem cell transplantation. Of 7 patients alive 1 year after treatment, 4 had a complete hematologic response, and all 4 experienced improvement in their factor X levels. One of 2 additional patients with partial hematologic responses had improvement in factor X. Thus, aggressive treatment of the underlying plasma cell dyscrasia in AL amyloidosis can lead to the amelioration of amyloid-related factor X deficiency.

[Decreased Quick percentage, acquired factor X deficiency, hemarthrosis and ecchymosis: amyloidosis]

A 68-year-old woman suffered from spontaneous hemarthrosis of the right elbow joint in april 1994. Cutaneous ekchymoses had been noted since summer 1993. Prothrombin time was prolonged (Quick percentage 40-50%) and was not corrected by prolonged administration of vitamin K. Coagulation studies showed isolated factor X (FX) deficiency without circulating FX inhibitor. This suggested the diagnosis of systemic amyloidosis which was retrospectively confirmed in small bowel biopsy specimens obtained one year before. Bilateral femoral head necrosis and femoral neck fracture due to amyloidosis, necessitated orthopedic surgery. The patient died four weeks postoperatively after several episodes of bleeding complications. Isolated FX deficiency may be hereditary but should--in the clinical context--also evoke the diagnosis of systemic amyloidosis. The possible bleeding tendency associated with amyloidosis is not attributable to acquired FX deficiency alone, but may also be caused by amyloid deposition in the microvasculature leading to acquired vascular hemorrhagic diathesis.

Successful treatment of transient acquired factor X deficiency by plasmapheresis with concomitant intravenous immunoglobulin and steroid therapy

Two patients with no history of previous bleeding diatheses presented with active bleeding from multiple body sites, declining hemoglobin levels, and markedly prolonged prothrombin times (PT) and activated partial thromboplastin times (aPTT) with incomplete correction on PT mix assays. Both patients demonstrated a severe deficiency of factor X (F.X) (<1%; reference range 60-150%). F.X levels and bleeding were refractory to multiple transfusions of fresh frozen plasma (FFP) in both patients. In contrast, daily therapeutic plasma exchange (PLEX) with concomitant administration of intravenous immunoglobulin (IV IgG) and steroids produced a rapid increase in F.X levels with cessation of bleeding, followed by stabilization and normalization of F.X levels and progressive correction of coagulation times. Neither patient has demonstrated a recurrence of the bleeding tendency following discontinuation of steroid therapy. These patients had transient acquired F.X deficiency, a rare coagulopathy, which can result in a lethal bleeding diathesis. An IgG inhibitor that selectively inhibited F.X activation in Russell's viper venom or tissue factor/F.VIIa assays was demonstrated in one patient's pretreatment plasma. Previous treatment of hemorrhage in transient acquired F.X deficiency has been prothrombin complex and/or activated clotting concentrates, which can be associated with transient hypercoagulable states. This is the first reported use of PLEX in transient acquired F.X deficiency. PLEX is safe, efficacious, and rapidly restores hemostasis in this rare acquired bleeding disorder.

Normalization of plasma factor X levels in amyloidosis after plasma exchange

Some patients with systemic light chain amyloidosis develop bleeding complications that can be caused by vascular infiltration with amyloid or by alterations of the coagulation or fibrinolytic systems. Factor X deficiency is the most common cause of bleeding manifestations, although deficiencies of other clotting factors, a disruption in the conversion of fibrinogen to fibrin, and circulating heparin-like anticoagulants have also been reported. Deficiency of factor X is a well-recognized cause of bleeding manifestations in patients with light chain amyloidosis. This acquired disorder appears to be secondary to adsorption of factor X to the amyloid fibrils. Previous studies have shown that infusion of plasma into patients with acquired factor X deficiency and amyloidosis induces a transitory improvement of the coagulation tests. However, there is a rapid return to pretransfusion levels. In this manuscript we report the clinical application of plasma exchange in the management of a patient with systemic light chain amyloidosis with acquired factor X deficiency.

Retroperitoneal amyloidosis, factor IX and X deficiency,and gastrointestinal bleeding

A patient with gastrointestinal bleeding due to amyloidosis-related factor X deficiency had extensive calcified retroperitoneal amyloid deposition that was visible on plain radiographs and then localized by computed tomography. The radiologic findings were important in arriving at the proper diagnosis despite negative biopsies.

Five novel point mutations: two causing haemophilia B and three causing factor X deficiency

Factors IX and X are plasma glycoproteins important in the middle phase of the coagulation cascade, and a bleeding disorder of variable severity results from abnormalities in the expression of either gene encoding these proteins. Nearly 380 unique molecular mechanisms cause factor IX deficiency, or haemophilia B, but only a limited number of mutations causing congenital factor X deficiency have been characterized to date. In this study enzymatic amplification has been used to examine the molecular basis for factor IX deficiency in two patients and factor X deficiency in two patients. Genomic DNA was isolated from each patient and synthetic oligonucleotide primers were used in the polymerase chain reaction to amplify each exon, splice junction and polyadenylation site. Amplified DNA was then cloned into pUC18 and sequenced. Five novel point mutations were identified, two occurring in the eighth exon of the factor IX gene and three in the eighth exon of the factor X gene. One of the haemophilia B mutations and one of the factor X mutations altered homologous histidine residues near the serine of the catalytic triad.

A unique circulating inhibitor with specificity for coagulation factor X

An 84-year-old woman presented with extensive cutaneous and gastrointestinal bleeding. Initial laboratory studies revealed a prolonged prothrombin time and activated partial thromboplastin time. Further investigations revealed a circulating anticoagulant with specificity for factor X. The patient's hemorrhage resolved with supportive measures only. Approximately 11 months after presentation, the inhibitor disappeared.

Vitamin K-dependent multifactor coagulopathy in Devon Rex cats

A coagulopathy attributable to a deficiency of vitamin K-dependent clotting factors (II, VII, IX, and X) was diagnosed in 3 Devon Rex cats. There was no evidence for exposure to vitamin-antagonist-related rodenticides. The cats did not have evidence of hepatic disease, gastrointestinal disease, or fat malassimilation. Oral treatment with vitamin K1 resulted in normalization of clotting factor concentrations. However, when treatment was discontinued in 2 cats, prothrombin and activated partial thromboplastin values became prolonged again, although the cats did not have clinical signs of a bleeding disorder.

Coagulation factor abnormalities as possible thrombotic risk factors after Fontan operations

Severe thromboembolism occurred in 3 of 37 patients who had undergone Fontan-type operations for correction of congenital heart defects several months to years after the operation. The patients were screened for coagulation factor abnormalities to find out whether known prothrombotic risk factors could explain the high frequency of thromboembolism. 63 abnormalities were found in 24 of the 37 patients. The commonest and most pronounced abnormality was deficiency of protein C, a known risk factor. Concentrations of antithrombin III and factors II and X were significantly lower in protein-C-deficient patients than in those with normal protein C concentrations. These findings suggest that the high thrombotic risk in these patients is caused or at least associated with an imbalance between procoagulant and anticoagulant factors.

Autologous bone marrow transplantation and factor XII, factor VII, and protein C deficiencies. Report of a new association and its possible relationship to endothelial cell injury

Four patients who underwent treatment with high-dose chemotherapy (HDC) and autologous bone marrow transplantation (ABMT) and in whom posttreatment deficiencies of Factor XII and protein C subsequently developed are reported. Factor VII or Factor X deficiencies also developed in several of these patients. Three of these patients experienced chemotherapy-related cardiac, hepatic, or pulmonary toxicity. It is believed by many that endothelial cell injury may be the underlying lesion responsible for these various organ system toxicities seen in the setting of ABMT, although direct evidence of this is lacking. It is proposed that the factor deficiencies described in this report may be an additional consequence of endothelial cell injury or dysfunction. These coagulation factor deficiencies may therefore serve as both a marker to follow these organ system toxicities with and as a useful tool to better study and understand the mechanisms underlying these events. Additionally, deficiencies of either Factor VII or Factor X developed in several patients that were of a sufficient magnitude such that factor replacement therapy would be indicated before any invasive procedures or in the event of significant hemorrhage.

Progressive systemic sclerosis with the nephrotic syndrome and acquired factor X deficiency

A patient with progressive systemic sclerosis (PSS) involving skin, digit, esophagus, and lung developed the nephrotic syndrome and rapidly progressive renal insufficiency. Renal pathology revealed capillary collapse, cellular crescents, arteriolar hyaline deposition, and mesangial proliferation. On immunofluorescence IgM, C3, and fibrinogen were present in mesangium and capillary walls. Prebiopsy coagulation screening revealed a factor X deficiency which caused substantial prolongation of the partial thromboplastin time without an overt bleeding diathesis. The acquired factor X deficiency resolved after fresh frozen plasma and vitamin K administration, although some spontaneous improvement was noted. Nephrotic syndrome may occasionally be seen in the acute fulminant form of PSS and should not deter diagnosis of PSS.

Systemic amyloidosis associated with factor X deficiency

An autopsy case of amyloidosis associated with factor X deficiency is reported. The patient showed a markedly decreased level of factor X (9% normal) and an extremely shortened half-life of intravenously infused factor X. Amyloid deposition was present in most of the visceral organs with special involvement of the liver and spleen. The amyloid in this case was thought to be AL protein, since it was potassium-permanganate-resistant and a small amount of Bence Jones protein was detected after dimethyl sulfoxide therapy. Electron microscopic study revealed a typical appearance of amyloid fibrils radiating from invaginated cell membrane of Kupffer cells, which may indicate rather rapid turnover of the amyloid. Rapidity and severity of amyloid deposition, especially in the liver and spleen, may play an important role in the development of the factor X deficiency associated with systemic amyloidosis.

Prolongation of thrombin and reptilase times in patients with amyloidosis and acquired factor X deficiency

A patient with acquired factor X deficiency due to amyloidosis had a prolonged thrombin time. Investigation of this abnormality suggested that an inhibitor of thrombin was present. A review of the literature demonstrated that prolonged thrombin time or reptilase time was present in many of the patients with acquired factor X deficiency due to amyloidosis. We were unable to relate prolongation of the thrombin time or reptilase time to the severity of bleeding. We believe that determination of thrombin and reptilase times should be part of the coagulation profile in all patients with acquired factor X deficiency.

[Factor X deficiency and systemic amylosis]

The case of a 52-year-old patient with systemic amylosis diagnosed upon examination of an osteomedullary biopsy specimen is reported. The most prominent clinical manifestation was a major hemorrhagic syndrome which was recognized as being a result of severe factor Stuart deficiency. The new classification of amyloses based on the latest biochemical and immunological findings is recalled. Current physiopathogenic speculations put emphasis on plasmocyte-macrophage cooperation. Lastly, factor Stuart deficiency, which is as classical as it is uncommon, could originate in the particular affinity of amyloid fibers for this factor and in a "mass effect" (quantity of amyloid substance directly exposed to blood flow), explaining why splenectomy is effective in some instances.

Bulimia nervosa complicated by deficiency of vitamin K-dependent coagulation factors

A 28-year-old woman manifested a hemorrhagic tendency caused by a deficiency of vitamin K-dependent coagulation factors. Her condition was diagnosed as bulimia nervosa in view of a previous history of anorexia nervosa and episodes of self-induced vomiting and purging. There were no remarkable lesions in her alimentary system. In treatment of bulimia nervosa, attention should be given not only to the loss of body fluids and electrolytes, but also to the possibility of a deficiency of vitamin K-dependent coagulation factors.

Transient, selective factor X deficiency and acute liver failure following chest infection treated with erythromycin BP

A 57-year-old man developed symptoms of a respiratory tract infection which was treated with erythromycin BP. He subsequently went into acute liver failure. Investigation of a very prolonged prothrombin time revealed a marked, selective factor X deficiency (1% of normal activity). He later recovered virtually normal liver function and completely normal factor X activity.

Characterization of amyloid deposits and P component from a patient with factor X deficiency reveals proteins derived from a lambda VI light chain

Amyloid fibrils were isolated from a spleen obtained at surgery from a 58-year-old white man with primary amyloidosis presenting with factor X deficiency and responding dramatically to splenectomy. Gel filtration on Ultragel ACA 54 in 5 M guanidine 1 M acetic acid yielded components with molecular weights between 17,000 and 13,000. Two of them (17K and 15K) were studied in detail. Antigenic and amino acid sequence analysis showed that these proteins were related to lambda VI immunoglobulin light chain. The predominant protein subunits of the amyloid fibril of the deposits (17K) was processed at the carboxy terminus in the same section of the constant region as the only other lambda VI amyloid protein previously reported. Amino terminal sequence of the 15K protein revealed not only degradation at the C terminal, but also minor degradation at the amino terminal (three residues difference from the 17K species). P component was also isolated from the spleen and characterized. This represents the first antigenic and sequence analysis of tissue amyloid proteins and P component from a patient presenting with factor X deficiency and another example of amyloid proteins derived from the newly discovered amyloidogenic lambda VI light chain subgroup.

Acquired isolated factor X deficiency associated with systemic amyloidosis. Case report and review of literature

The demonstration of acquired isolated factor X deficiency and of a biclonal homogeneous lambda and kappa light polypeptide chain proteinuria in a patient of 49 years having an obscure hepatomegaly gave clinical evidence for the rate, amyloidosis-associated factor X deficiency, which could be proven by postmortem examination. The mechanisms by which amyloid may affect factor X levels in this case may be preferentially binding to the amyloid fibrils of lambda light chain type.