Background: A simple assay that can discriminate between localized and systemic amyloidosis is needed.
Methods: Coagulation and fibrinolysis parameters were measured in subjects with active or progressive systemic amyloidosis (Group A; 9 patients), systemic amyloidosis in complete remission (Group B; 6 patients), localized AL amyloidosis (Group C; 6 patients), monoclonal gammopathy of undetermined significance (Group D; 5 patients), chronic glomerulonephritis with proteinuria (Group E; 22 patients), or glomerulonephritis in complete remission (Group F; 11 patients).
Results: No significant differences were noted between Group A and the other groups in the international normalized ratio of prothrombin time, activated partial thromboplastin time, and levels of antithrombin and plasminogen. Levels of thrombin-antithrombin (TAT) complexes, fibrinogen, fibrinogen degradation product d-dimers, and plasmin-α2-plasmin inhibitor complexes (PIC) were significantly elevated in Group A. All patients that showed TAT complexes, fibrinogen, and PIC levels greater than 4.2 ng/mL, 399 mg/dL, and 1.4 μg/mL, respectively, had active or progressive systemic amyloidosis. All patients with TAT complex levels less than 3.6 ng/mL, fibrinogen levels less than 355 mg/dL, and PIC levels less than 0.9 μg/mL had localized AL amyloidosis.
Conclusion: Analyses of TAT complexes, fibrinogen, and PIC can be used to differentiate localized AL amyloidosis from systemic amyloidosis.