Rapid anti-HPA-1a antibody quantification with a Luminex bead-based assay: A method evaluation

Area of Science:

• Immunology
• Transfusion Medicine
• Neonatal Care

Background:

• High levels of human platelet antigen-1a (HPA-1a) antibodies are linked to severe foetal and neonatal alloimmune thrombocytopaenia (FNAIT).
• The current gold standard for quantifying anti-HPA-1a antibodies, the MAIPA assay, is time-consuming and requires specialized laboratories.
• There is a need for a more accessible and efficient method for anti-HPA-1a antibody measurement.

Purpose of the Study:

• To evaluate the performance of the commercially available bead-based Luminex assay, PakLx, for the quantitative measurement of anti-HPA-1a antibodies.
• To compare the PakLx assay with the established MAIPA assay.

Main Methods:

• Plasma samples from 42 women with HPA-1a-negative infants experiencing thrombocytopaenia were analyzed.
• Anti-HPA-1a antibody levels were quantified using both the MAIPA assay (expressed in IU/mL) and the Luminex PakLx assay (expressed as mean fluorescence intensity, MFI).

Main Results:

• The PakLx assay showed 97.6% agreement with the MAIPA assay in classifying results as positive or negative.
• High correlation (R²=0.92) was observed between PakLx MFI values and MAIPA IU/mL.
• PakLx MFI values were successfully converted into semi-quantitative categories: high, intermediate, and low anti-HPA-1a levels.

Conclusions:

• The Luminex PakLx assay demonstrates high agreement with the MAIPA assay for determining anti-HPA-1a antibody levels.
• PakLx offers a significantly faster laboratory turnaround time compared to MAIPA.
• The PakLx assay has potential predictive value in clinical settings for managing FNAIT.