A new Eu(3+)-labeled method for anticardiolipin antibody IgM

Area of Science:

• Immunology
• Clinical Chemistry
• Biomedical Diagnostics

Background:

• Anticardiolipin antibodies (aCL) testing is standard for antiphospholipid syndrome (APS) diagnosis.
• Current methods require improved quantitative detection of aCL-IgM for accurate APS classification.
• A novel time-resolved fluoroimmunoassay (TRFIA) was developed for enhanced aCL-IgM detection.

Purpose of the Study:

• To develop and validate a new TRFIA for quantitative detection of aCL-IgM.
• To improve the accuracy and timeliness of APS diagnosis.
• To establish a more sensitive and reliable immunoassay for aCL-IgM.

Main Methods:

• A novel immunoassay using cardiolipin and bovine anti-β2 glycoprotein-I as antigen was established.
• Eu(3+)-labeled rabbit antihuman IgM served as the conjugate in the TRFIA.
• Assay precision, sensitivity, specificity, recovery, stability, and comparison with ELISA were evaluated.

Main Results:

• The TRFIA demonstrated a lower detection limit (0.1 MPL U/ml) and a wider detectable range compared to commercial ELISA kits.
• Excellent linearity was observed within the range of 0.16 to 2,630.9 MPL U/ml.
• High clinical diagnostic specificity (98%), good stability, and strong correlation (0.955) with ELISA were achieved.

Conclusions:

• The developed aCL-IgM TRFIA offers a more sensitive and reliable diagnostic approach for APS.
• This assay facilitates more accurate and timely classification of APS patients.
• Further clinical validation is recommended to confirm its utility in diagnosing APS.