A simple method for detection of human factor IX inhibitor using ELISA

Area of Science:

• Hematology
• Immunology
• Diagnostic Assays

Background:

• Factor IX inhibitors (FIXinh) complicate hemophilia B treatment.
• Accurate detection of FIXinh is crucial for effective management.
• Existing assays may have limitations in specificity or sensitivity.

Purpose of the Study:

• To develop and validate a simple Enzyme-Linked Immunosorbent Assay (ELISA) for detecting Factor IX inhibitors (FIXinh).
• To assess the sensitivity and specificity of the developed ELISA.
• To evaluate the assay's performance in distinguishing FIXinh from other anticoagulants.

Main Methods:

• Development of a simple ELISA for FIX inhibitor detection.
• Linearity assessment of absorbance versus plasma dilutions with known FIXinh.
• Comparison of ELISA results with the Bethesda Inhibitor Assay.
• Evaluation in patient cohorts: hemophilia B with/without FIXinh, hemophilia A with FVIII inhibitors, and SLE with lupus anticoagulant.

Main Results:

• The ELISA demonstrated a linear relationship between absorbance and FIXinh concentration across a wide dilution range.
• The assay can detect as low as 0.219 Bethesda units/ml of FIXinh.
• ELISA results for hemophilia B patients with FIXinh were significantly higher than normal controls and other patient groups.
• The presence of other anticoagulants did not affect FIXinh detection in hemophilia B patients.

Conclusions:

• A simple ELISA is a sensitive and specific method for detecting Factor IX inhibitors.
• This ELISA can reliably differentiate FIXinh in hemophilia B patients, even in the presence of other anticoagulants.
• The developed assay offers a valuable tool for diagnosing and managing hemophilia B with inhibitors.