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[Disorders in the conversion of fibrinogen to fibrin in patients with multiple myeloma]
Abstract:
A prolonged thrombin clotting time was found in 15 of 85 patients with multiple myeloma. Among those with abnormal clotting time in 9 cases (60.0%) the M protein was classified as IgG-lambda, in 1 (6.6%) as IgA-lambda, in 2 (13.3%) as IgG-kappa, and in 3 (20.3%) as IgA-kappa. There was no correlation between the prolongation of thrombin time and occurrence of bleeding. The reptilase clotting time was parallel to the thrombin time. The addition of calcium chloride partially corrected both clotting times. The isolated M proteins IgG-lambda and IgG-kappa from patients with prolonged thrombin time at the concentration of 25-50 mg/ml inhibited the polymerization of fibrin monomers but had no effect on the amidolytic and proteolytic action of thrombin.
Insights
Fifteen multiple myeloma patients showed prolonged thrombin clotting time, primarily linked to IgG-lambda M proteins. This clotting abnormality did not correlate with bleeding events.
Area of Science:
- Hematology
- Oncology
- Biochemistry
Context:
- Multiple myeloma is a plasma cell malignancy.
- Coagulopathy can occur in multiple myeloma patients.
- M proteins are monoclonal immunoglobulins produced by myeloma cells.
Purpose:
- To investigate the association between M protein characteristics and prolonged thrombin clotting time in multiple myeloma.
- To determine the mechanism by which M proteins affect coagulation.
Summary:
- A prolonged thrombin clotting time was observed in 15 out of 85 multiple myeloma patients.
- The majority of abnormal clotting times were associated with IgG-lambda M proteins.
- Reptilase clotting time results paralleled thrombin time, and calcium chloride partially corrected both.
- Isolated IgG-lambda and IgG-kappa M proteins inhibited fibrin monomer polymerization but did not affect thrombin's enzymatic activity.
Impact:
- Identifies a specific M protein subtype (IgG-lambda) associated with coagulation abnormalities in multiple myeloma.
- Suggests that M proteins interfere with fibrin polymerization, contributing to prolonged clotting times.
- Provides insights into the hemostatic challenges faced by multiple myeloma patients.