Flow cytometric human leukocyte antigen-B27 typing with stored samples for batch testing

Area of Science:

• Immunology
• Clinical Diagnostics
• Hematology

Background:

• Flow cytometry (FC) is extensively used for diagnosing spondyloarthropathies via HLA-B27 typing.
• Batch testing of stored patient blood samples can improve efficiency and control procurement.
• Investigating optimal storage methods for FC HLA-B27 typing is crucial.

Purpose of the Study:

• To evaluate different patient blood sample storage methods for flow cytometry HLA-B27 typing.
• To determine the most effective method for preserving sample integrity and diagnostic accuracy.

Main Methods:

• Four storage methods were compared: whole blood at room temperature, frozen mononuclear cells, frozen white blood cells (WBCs), and frozen platelets (FPLT).
• Mean fluorescence intensity (MFI) ratios (B27 MFI ratio, B7 MFI ratio, and B7/B27 ratio) were used for HLA-B27 and HLA-B7 assignment.

Main Results:

• Frozen platelets (FPLT) demonstrated superior performance compared to other storage methods.
• FPLT achieved 100% sensitivity and 99.3% specificity for HLA-B27 assignment in DNA-typed samples (N=164) using specific MFI ratio criteria.

Conclusions:

• The FPLT method provides a simple, economical, and accurate approach for FC HLA-B27 typing with stored samples.
• This method has the potential to enhance standard FC typing when combined with DNA-based methods for spondyloarthropathy diagnosis.