Routine Solid Phase Multiplex Anti-HLA Antibody Tests Predict Platelet Refractoriness

Area of Science:

• Immunology
• Transplantation Science
• Hematology

Background:

• Alloimmune-mediated platelet refractoriness (alloPR) poses a significant challenge in patient care, particularly for hematopoietic progenitor cell transplant recipients.
• Currently, no validated screening methods exist to identify patients at risk for developing alloPR.

Purpose of the Study:

• To determine if bead-based human leukocyte antigen (HLA) antibody tests can predict the risk of developing HLA alloPR.
• To evaluate the efficacy of HLA antibody screening in identifying at-risk patients.

Main Methods:

• Retrospective analysis of hematopoietic progenitor cell transplant patients screened for HLA antibodies prior to developing refractoriness.
• Comparison of phenotype bead screening results between patients who developed alloPR and those who did not.

Main Results:

• Seven of 27 patients developed alloPR.
• Significantly higher panel reactive antibody (PRA) and mean fluorescence intensity (MFI) of the 10 most reactive beads were observed in patients who developed alloPR (P < .001).
• PRA >30% and mean MFI ≥1,500 in the most reactive beads identified at-risk patients. HLA-compatible platelets improved posttransfusion count increments.

Conclusions:

• Phenotype bead assay for HLA antibody screening may prospectively identify patients at risk for alloPR.
• Further clinical trials are necessary to validate these predictive findings and guide clinical practice.