Combined functional and immunochemical analysis of normal and abnormal human factor X

Area of Science:

• Biochemistry
• Hematology
• Immunology

Background:

• Human Factor X (FX) is a crucial coagulation factor.
• Understanding FX molecular forms and antigen levels is vital for diagnosing bleeding disorders.

Purpose of the Study:

• To characterize human Factor X.
• To develop a specific radioimmunoassay for human FX antigen.
• To compare FX antigen levels with coagulant activity in various patient groups.

Main Methods:

• Isolation and characterization of human Factor X.
• Development of a monospecific radioimmunoassay for FX antigen.
• Analysis of FX antigen and coagulant activity in normal and deficient plasmas.

Main Results:

• Two biologically active molecular forms of FX were identified.
• The radioimmunoassay demonstrated specificity for human FX.
• A 30% difference between FX antigen and coagulant activity was observed, attributed to inactive FX molecules.
• FX from various patient plasmas was immunochemically similar to purified FX.

Conclusions:

• The developed radioimmunoassay accurately quantifies human FX antigen.
• The presence of FX molecules without coagulant activity impacts overall assessment.
• Analysis of FX antigen and activity aids in characterizing deficiencies in warfarin-treated, acquired, and congenital FX-deficient patients.