Normalization of plasma factor X levels in amyloidosis after plasma exchange

Prevalence, clinical characteristics and treatment outcome of factor X deficiency in a consecutive cohort of primary light-chain amyloidosis

Factor X (FX) deficiency is prevalent in light-chain (AL) amyloidosis but its clinical significance was not investigated deeply. We conducted a retrospective analysis of a consecutive cohort with 207 primary AL amyloidosis patients. FX deficiency was present in 129 patients (62.3%). Those with FX deficiency had higher dFLC (299.6 mg/L vs. 102.3 mg/L, P < 0.001), higher cardiac troponin I (0.05 μg/L vs. 0.02 μg/L, P < 0.001) and N-terminal pro-brain natriuretic peptide (3115 ng/L vs. 392 ng/L, P < 0.001), and more patients with bone marrow plasma cells > 10% (18.0% vs. 4.3%, P = 0.008). The prevalence of FX deficiency increased with the Mayo 2004 stage. FX-deficient patients exhibited inferior overall survival (P < 0.001) and progression-free survival (P < 0.001) than others. Fifty-five patients with FX deficiency received retesting of FX activity after anti-plasma cell therapy. The median variation in FX activity was + 6.8% (range, -24.5% ~ +73.4%). Better improvement of FX activity was observed in patients with complete hematologic response (+18.2% vs. +4.0%, P = 0.036) and at least one organ response (+14.4% vs. +3.4%, P = 0.024). FX deficiency is associated with a heavier disease burden and poorer survival in primary AL amyloidosis. Improvement of FX activity tends to appear in patients with better hematologic and organ responses after chemotherapy.

Coagulation Abnormalities in Light Chain Amyloidosis

OBJECTIVE

To assess the prevalence of coagulation abnormalities in patients with systemic light chain (AL) amyloidosis and their association with disease-related characteristics, disease progression, and survival.

PATIENTS AND METHODS

This is a retrospective study of patients with AL amyloidosis seen at Mayo Clinic, Rochester, Minnesota, from January 1, 2006, to December 31, 2015. We studied the association between abnormal coagulation parameters and baseline characteristics and their association with survival outcomes.

RESULTS

The study included 411 patients. Abnormalities at diagnosis included prolonged clotting times and coagulation factor deficiencies; prolonged prothrombin time (PT) and factor X (FX) deficiency were found in 19% (73 of 390) and 43% (177 of 411) of patients, respectively. The FX deficiency was associated with higher Mayo stage, involvement of more than 1 organ, liver and cardiac involvement, and greater than 10% bone marrow plasma cells. On univariate analysis, the risk for disease progression or death was higher in patients with abnormal values for PT and factor V, factor VII (FVII), FX, and factor XII compared with those with normal values. Prolonged PT and FVII and FX deficiencies were independent predictors of death after adjusting for Mayo stage and more than 1 organ involvement. Only 106 patients had repeat testing after treatment; no clear relationship was found between treatment response and changes in coagulation parameters.

CONCLUSION

Coagulation abnormalities occur in a significant proportion of patients with AL amyloidosis and are associated with advanced disease and inferior outcomes. Larger studies are needed to establish whether a relationship exists between treatment response and improvement in individual parameters.

Acquired Factor X Deficiency in Patients With Primary Light Chain Amyloidosis

Acquired factor X (FX) deficiency is a rare but serious complication of primary amyloidosis, presumably caused by the binding of amyloid proteins to the clotting factors. The prolonged prothrombin time, partial thromboplastin time, and low FX level, which are correctable by mixing study, are the disease hallmarks. An immediate goal of care is to stop bleeding. Clotting factor replacement requires close monitoring of coagulogram and FX levels due to varying FX clearance among patients. High-purity FX is currently approved for hereditary FX deficiency and has been successfully used in some acquired FX deficiency cases. Ongoing bleeding risk complicates the treatment decision. Novel therapies yielding rapid and deep response reduce amyloid protein production and improve long-term outcome.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice - Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Eighth Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating and categorizing indications for the evidence-based use of therapeutic apheresis (TA) in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Eighth Edition of the JCA Special Issue continues to maintain this methodology and rigor in order to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Eighth Edition, like its predecessor, continues to apply the category and grading system definitions in fact sheets. The general layout and concept of a fact sheet that was introduced in the Fourth Edition, has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of TA in a specific disease entity or medical condition. The Eighth Edition comprises 84 fact sheets for relevant diseases and medical conditions, with 157 graded and categorized indications and/or TA modalities. The Eighth Edition of the JCA Special Issue seeks to continue to serve as a key resource that guides the utilization of TA in the treatment of human disease.

Long-Term Outcomes of Patients With Amyloidosis Following Kidney Transplant

OBJECTIVES

Reported graft and patient survival rates in amyloidosis after renal transplant differ considerably between studies.

MATERIALS AND METHODS

Group 1 included 24 patients who had end-stage renal disease secondary to amyloidosis. Group 2 (the control group) included 24 consecutive patients who had kidney disease secondary to various causes other than amyloidosis. Comparisons between groups were made for kidney and patient survival rates and other complications following kidney transplant. We also compared survival rates of patients in group 1 versus another control group that included patients with amyloidosis who were treated with hemodialysis (group 3; n = 25).

RESULTS

Mean follow-up was 109.5 ± 79.8 months. Biopsy-proven acute rejection and graft failure rates were not significantly different between groups. In group 1 versus group 2, the cumulative 10-year and 20-year patient survival rates were 68.2% versus 86.1% and 36.9% versus 60.3%, respectively (P = .041). Survival was not significantly different in group 1 compared with group 2 and group 3, although patients in group 3 had significantly shorter duration of time to death after the start of renal replacement therapy.

CONCLUSIONS

Patient survival may be lower in kidney transplant recipients with amyloidosis compared with patients with end-stage renal disease due to other causes. However, graft failure and acute rejection rates seem to be similar.

Factor X deficiency: an uncommon presentation of AL amyloidosis

Factor X deficiency is the most common coagulation factor deficiency amongst patients with AL amyloidosis. It presumably occurs due to adsorption of factor X to amyloid fibrils. The deficiency of this factor, in conjunction with other hemostatic defects, can cause bleeding complications. A case of acquired factor X deficiency due to AL amyloidosis is reported, where abnormal coagulation parameters were the only presenting feature.

Presurgical plasma exchange is ineffective in correcting amyloid associated factor X deficiency

In patients with rare factor deficiencies, for which no factor concentrates are available, plasma exchange (PE) is an option for raising the desired factor level to approximately 80% for surgery. We report a case of acquired factor X (FX) deficiency due to amyloidosis that required urgent surgical repair of an AV fistula aneurysm. This patient had a FX level of 3% at presentation; after 1.5 volume PE with fresh frozen plasma (FFP), his post-exchange FX was only 5%, indicating rapid adsorption of FX to amyloid fibrils. He was managed successfully with FEIBA during surgery.

Factor X deficiency

Factor X is one of the vitamin K-dependent serine proteases. It plays a crucial role in the coagulation cascade, as the first enzyme in the common pathway of thrombus formation. The gene for factor X maps to the long arm of chromosome 13, approximately 2.8 kb downstream of the factor VII gene. The gene consists of eight exons, each of which encodes a specific functional domain within the protein. Both the gene structure and the amino acid sequence show homology to other vitamin K-dependent clotting factors, suggesting their origin in a common ancestral protein. Factor X deficiency is one of the rarest of the inherited coagulation disorders. Inheritance is in an autosomal recessive manner. The clinical phenotype is of a variable bleeding tendency. Homozygous factor X deficiency has an incidence of 1:1,000,000 in the general population. Heterozygotes are often clinically asymptomatic. Acquired factor X deficiency is rare, but when it occurs it is usually in association with amyloidosis. Treatment of factor X deficiency involves replacement of the protein with either fresh frozen plasma or prothrombin complex concentrates, although the latter should be used with caution as infusion may be associated with an increased risk of thrombosis.

Presurgical plasma exchange for severe factor V deficiency

We report two patients with severe congenital factor V deficiency, one of whom also had a factor V inhibitor, who required correction of their coagulopathy prior to surgical procedures. They underwent plasma exchange (PE) with fresh frozen plasma or solvent/detergent treated plasma (S/DP), with achievement of factor V levels satisfactory for hemostasis for their procedures. PE makes it possible to raise factor levels quickly and sufficiently without volume overload. In addition, transient reduction of inhibitor titers by PE may improve the level of correction achievable during the perioperative period. The advent of S/DP promises to provide an added increment of safety in patients exposed to significant volumes of plasma during PE.

Recombinant human factor X: high yield expression and the role of furin in proteolytic maturation in vivo and in vitro

Factor X/Xa plays a pivotal role in the coagulation cascade and exhibits a therapeutic potential for the treatment of factor X-deficient as well as FVIII and FIX inhibitor patients. This report describes the establishment of Chinese hamster ovary cell clones expressing recombinant human factor X up to 120 microg/mL x day and 78 microg/10(6) cells x day, that is to 100-fold higher levels than reported previously. Although propeptide removal and single chain precursor to light and heavy chain processing as well as vitamin K-dependent gamma-carboxylation became impaired at these expression levels, up to 25% of the recombinant human factor X produced was active. This represents the highest functional activity ever reported for a vitamin K-dependent protein at such an expression level. Expression of recombinant human factor X in Chinese hamster ovary cells lacking the endoprotease Furin revealed that propeptide removal still occurred, whereas single chain precursor to light/heavy chain processing was abolished. This suggests that a protease different from Furin mediates propeptide removal, a unique finding compared with the other vitamin K-dependent coagulation factors. In contrast, exposure of incompletely processed rFX molecules to soluble recombinant Furin in vitro mediated both of these cleavage reactions despite the absence of a typical argP4-xP3-lys/argP2-argP1 Furin cleavage site in the propeptide, indicating relaxed specificity in vitro. Concomitantly with the degree of processing, the functional activity of recombinant human factor X increased. Interestingly, Furin was shown to even perform correct N-terminal proteolytic trimming of FX molecules truncated amino-terminal to the P3 residue in vitro. Depending on the absence or presence of warfarin in the culture media, as well as on the processing state, four distinct recombinant human factor X light chain isoforms were observed and their structure characterized. One of these light chain forms correlated with the functional activity. Finally, the distribution of the individual light chain isoforms suggests that gamma-carboxylation may be a prerequisite for propeptide removal.