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Combined factor IX and protein C deficiency in a child: thrombogenic effects of two factor IX concentrates
C Negrier1, J Vial, C Vinciguerra
1Centre de Traitement de l'Hémophilie, Hôpital Edouard Herriot, Lyon, France.
Insights
A child with hemophilia B and protein C deficiency showed elevated prothrombin fragment F1+2 levels after factor IX concentrate. Immunopurified factor IX concentrate resulted in a lower increase, suggesting reduced thrombotic risk.
Area of Science:
- Hematology
- Coagulation disorders
- Thrombosis
Background:
- A rare case of combined factor IX and protein C deficiency presented as hemophilia B.
- Elevated prothrombin fragment F1+2 levels were observed in this patient, increasing post-factor IX concentrate infusion.
Observation:
- The study monitored factor IX, prothrombin fragment F1+2, and D-dimer levels before and after infusion of an immunopurified factor IX concentrate.
- Compared to a previous ion-exchange chromatography-purified concentrate, the immunopurified concentrate caused a smaller increase in prothrombin fragment F1+2.
Findings:
- Prothrombin fragment F1+2 levels increased post-infusion but returned to baseline within 6 hours.
- The immunopurified factor IX concentrate demonstrated a potentially lower thrombogenic risk compared to less purified forms.
Implications:
- Immunopurified factor IX concentrates may be preferable for patients requiring repeated infusions, such as during surgery.
- This highlights the advantage of highly purified factor IX concentrates in mitigating thrombotic risks in specific clinical scenarios.
Abstract:
We have recently described an unusual situation which involved a combination of a factor IX and a protein C deficiency in a young child who presented, according to the bleeding tendency, as a hemophilia B patient. In this particular hemophiliac, baseline prothrombin fragment F1 + 2 levels were unexpectedly elevated and increased after an injection of a very high purity factor IX concentrate. This observation raised a question regarding the substitution schedule in the case of repeated injections of factor IX, since the thrombotic tendency has been a major concern with some factor IX concentrates. We monitored factor IX, prothrombin fragment F1 + 2, and D-dimer plasma levels before and during the 6 hr following the injection of an immunopurified factor IX concentrate. The results showed an increase in the F1 + 2 levels after the factor IX injection, but an increase lower than previously observed with an ion-exchange chromatography-purified concentrate. Furthermore, the F1 + 2 level returned to baseline value 6 hr after administration. This factor IX concentrate seems to be best for use in the patient where repeated injections are involved (as employed during surgery). Moreover, the data point out the advantage of a monoclonal antibody-purified factor IX concentrate over less purified concentrates in a specific situation, with regard to the thrombogenic risk.