The platelet-specific alloantigen PlA1 (HPA-1a): a comparison of flow cytometric immunophenotyping and genotyping using polymerase chain reaction and restriction fragment length polymorphism in a Swedish blood donor population.

• BACKGROUND: There is an increasing interest in the development of rapid and reliable techniques for platelet alloantigen typing. STUDY DESIGN AND METHODS: By use of standardized flow cytometry and a specific human alloantiserum, 236 Swedish blood donors were immunophenotyped for the platelet-specific alloantigen, PlA1 (HPA-1a). RESULTS: Ten individuals (4.2%) had low fluorescence intensities and were considered PlA1-negative (HPA-1a-negative); all of them also demonstrated a PlA2/PlA2 (HPA-1b/1b) genotype in a polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) assay of the underlying DNA polymorphism. The remaining population had clear positive fluorescence and was regarded as PlA1-positive (HPA-1a-positive). The fluorescence distribution histogram among PlA1-positive (HPA-1a-positive) individuals was dome-shaped, and those individuals who were homozygous for PlA1 (HPA-1a) could not be distinguished from those who were heterozygous. This finding was further substantiated by PCR-RFLP analysis of the PlA1/PlA2 (HPA-1a/1b) genotype; a heterozygous genotype was found among those having a medium fluorescence intensity as well as among those having a strong fluorescence intensity. CONCLUSION: Flow cytometry is a valuable tool for large-scale detection of PlA1 (HPA-1a). However, flow cytometry based on only one antiserum cannot distinguish between homozygous and heterozygous carriers of PlA1 (HPA-1a). For zygosity testing and when platelets are difficult to obtain, the PCR-RFLP technique is the assay of choice.

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Hematologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Hematology (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Annan klinisk medicin (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Other Clinical Medicine (hsv//eng)

Keyword

Antigens

Human Platelet

genetics

immunology

Base Sequence

Flow Cytometry

Fluorescent Antibody Technique

Genotype

Humans

Immunophenotyping

Molecular Sequence Data

Polymerase Chain Reaction

Polymorphism

Restriction Fragment Length

Sweden

Publication and Content Type

ref (subject category)

art (subject category)