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A non-immunological phospholipid-dependent coagulation inhibitor associated with IgGlambda-type multiple myeloma
Osamu Takamiya1, Shinichiro Machida, Masahiro Okuda
1Laboratory of Hematology, Department of Biomedical Laboratory Sciences, School of Health Sciences, Shinshu University, Matsumoto Asahi, Japan. itosamu@gipac.shinshu-u.ac.jp
American Journal of Hematology
|December 26, 2003
Summary
This study details a rare IgG lambda multiple myeloma case with prolonged clotting times. The patient's IgG demonstrated lupus anticoagulant-like activity, inhibiting phospholipid-dependent coagulation pathways.
Area of Science:
- Hematology
- Immunology
- Clinical Biochemistry
Background:
- Investigated a rare IgG lambda multiple myeloma case presenting with significantly prolonged prothrombin time (PT) and activated partial thromboplastin time (APTT).
- Addressed the diagnostic challenge posed by prolonged coagulation parameters in multiple myeloma patients.
Observation:
- The patient's IgG inhibited coagulation initiated by modified Russell's viper venom (mRVVT) but not by Factor Xa (FXa).
- Modified PT (mPT) and mAPTT assays indicated inhibition of FXa generation in both intrinsic and extrinsic pathways.
- The IgG interfered with protein C and Factor X (FX) activity, suggesting broad pathway inhibition.
Findings:
- Lupus anticoagulant (LA)-like activity was identified in the patient's IgG, inhibiting phospholipid-dependent coagulation across all pathways.
- This inhibitory activity was dependent on phospholipid concentration and required an intact IgG structure, as F(ab')2 and Fc fragments lacked activity.
- No binding was observed to cardiolipin-beta2GPI complex, beta2GPI, prothrombin, or phospholipids, suggesting a non-immunological inhibitory mechanism.
Implications:
- The findings suggest a novel mechanism of coagulation inhibition in multiple myeloma, potentially impacting bleeding risk assessment.
- Understanding this non-immunological inhibition of phospholipid-dependent coagulation is crucial for managing patients with similar hematological conditions.
- Further research is needed to elucidate the precise molecular interactions underlying this IgG-mediated coagulation interference.